The recent “ring of fire” solar eclipse looked stunning across portions of North and South America and we now have a new view of the stellar event. The Deep Space Climate Observatory (DSCOVR) satellite created the image of the eclipse on Saturday October 14, depicting the mostly blue Earth against the darkness of space, with one large patch of the planet in the shadow of the moon. 

[Related: Why NASA will launch rockets to study the eclipse.]

Launched in 2015, DSCOVR is a joint NASA, NOAA, and U.S. Air Force satellite. It offers a unique perspective since it is close to 1 million miles away from Earth and sits in a gravitationally stable point between the Earth and the sun called Lagrange Point 1. DSCOVR’s primary job is to monitor the solar wind in an effort to improve space weather forecasts. 

A special device aboard the satellite called the Earth Polychromatic Imaging Camera (EPIC) imager took this view of the eclipse from space. According to NASA, the sensor gives scientists frequent views of the Earth. The moon’s shadow, or umbra, is falling across the southeastern coast of Texas, near Corpus Christi.

An annular solar eclipse occurs when the moon moves between Earth and the sun. The sun does not vanish completely in this kind of eclipse. Instead, the moon is positioned far enough from Earth to keep the bright edges of the sun visible. This is what causes the “ring of fire,” as if the moon has been outlined with bright paint.

While this year’s event could be seen to some degree across the continental United States, the 125-mile-wide path of annularity began in Oregon around 9:13 AM Pacific Daylight Time. The moon’s shadow then moved southeast across Nevada, Utah, Arizona, Colorado, and New Mexico, before passing over Texas and the Gulf of Mexico. It continued south towards Mexico’s Yucatan, Peninsula, Belize, Honduras, Nicaragua, Costa Rica, Panama, Colombia, and Brazil

Unlike the colorful Aurora Borealis, eclipses are much easier to predict. Scientists can say when annular and solar eclipses will happen down to the second centuries in advance. The precise positions of the moon and the sun and how they shift over time is already known, so scientists can see how the moon’s shadow will fall onto Earth’s globe. Advances in computer technology have also enabled scientists to even chart eclipse paths down to a range of a few feet.

[Related: We can predict solar eclipses to the second. Here’s how.]

The next annular solar eclipse will be at least partially visible from South America on October 2,2024. One of these ‘ring of fire’ eclipses will not be visible in the United States until June 21, 2039. However, a total solar eclipse will darken the sky from Maine to Texas on April 8, 2024. There is still plenty of time to get eclipse glasses or make a pinhole camera to safely watch the next big celestial event. 

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On Saturday, October 14, you’ll be able to watch an annular “ring of fire” eclipse as the moon passes in front of the sun at a distance where it’s unable to cover all of Earth’s nearest star. But only an exclusive crowd will be able to witness the event in its fully blazing glory—unless you know where to look.

Although it may be too late to travel to one of the best locations to watch this year’s final solar eclipse, nearly everyone in all 50 US states will have a chance to catch at least a glimpse (sorry western Alaska and western Hawaii). The 125-mile-wide path of annularity, however, will stretch from Oregon to Texas and cross just nine states before continuing on to Central and South America. You’ll only be able to see the sun form a fiery halo around the moon along that route. If you’re outside its range, you can simply load up one of several official livestreams to see what you’re missing.

How to watch the October 14, 2023 eclipse in person

The path of annularity will enter the US in Oregon at 12:13 p.m. Eastern Time (9:13 a.m. Pacific Time) and leave Texas at 1:30 p.m. ET (12:03 p.m. Central Time). The “ring of fire,” will pass over 29 national park sites and dozens of other pieces of public land. Worldwide, about 33 million people will be able to see it firsthand, while everyone else will have to settle for a less dramatic experience.

No matter where you are, make sure you’re wearing protective glasses to avoid damaging your eyes if you plan to look directly at the eclipse, or make a pinhole camera to project the event onto a sheet of paper. And of course, weather conditions may make it hard or impossible to see anything, so take note of the forecast.

If you want to know exactly what to expect where you are, astronomy website Time and Date has an interactive map that will help you set your eclipse-viewing plans. Once you’ve opened the map, click the magnifying glass icon on the left to open the search menu. Type the name of any city or town into the search bar and select it from the list that populates underneath. A pin will appear on the map and a box full of eclipse data will show up under the search bar.

That data will show you how much of the moon will cover the sun at that location, when the eclipse will begin and end there, when maximum coverage will occur, and the weather forecast for that spot on the globe. If you click the play icon next to the duration, you’ll go to another page where you can watch a simulation of what the eclipse will look like at that exact spot.

How to watch the annular “ring of fire” eclipse online

Just because you aren’t part of the 0.41 percent of people in the world who will be able to physically bear witness to the celestial spectacle doesn’t mean you’re stuck with whatever’s happening in the sky above you. All you have to do is turn your eyes away from the wonders of the natural world and look at a screen—there are four livestreams we think will offer an exquisite show.

The Exploratorium’s livestreams

The San Francisco-based Exploratorium will be broadcasting two livestreams starting at 8 a.m. PT (11 a.m. ET), one from their telescopes in Valley of the Gods, Utah, and another from their telescopes in Ely, Nevada. They will also broadcast Spanish-language coverage of the event starting at 9 a.m. PT (12 p.m. ET) on YouTube.

According to Time and Date, annularity—the “ring of fire”— will last 4 minutes and 46 seconds at the Valley of the Gods. There are morning clouds in the forecast, though, so the view might be obscured, but this has the potential to be the most scenic livestream on our list. 

• Eclipse start: 9:10 a.m. Mountain Time (11:10 a.m. ET)
• “Ring of fire” start: 10:29 a.m. MT (12:29 p.m. ET)

In Ely, meanwhile, annularity will last for 3 minutes and 38 seconds. The weather is expected to be partly cloudy, so the eclipse could be hard to see.

• Eclipse start: 8:07 a.m. PT (11:07 a.m. ET)
• “Ring of fire” start: 9:24 a.m. PT (12:24 p.m. ET)

Time and Date’s livestream

Time and Date’s eclipse chasers will be broadcasting a livestream from Roswell, New Mexico. There, according to the website’s own interactive map, the annularity will last for 4 minutes and 41 seconds. It’s expected to be sunny there, so the view should be clear.

• Eclipse start: 9:15 a.m. MT (11:15 a.m. ET)
• “Ring of fire” start: 10:38 a.m. MT (12:38 p.m. ET)

NASA’s livestreams

NASA, of course, will also be livestreaming the eclipse, with feeds from Kerrville, Texas, and Albuquerque, New Mexico, starting at 11:30 a.m. ET. Annularity will last 4 minutes and 14 seconds at Kerrville, according to Time and Date.

• Eclipse start: 10:22 a.m. CT (11:22 a.m. ET)
• “Ring of fire” start: 11:50 a.m. CT (12:50 p.m. ET)

At Albuquerque, which is supposed to have sunny skies during the eclipse, annularity will last 4 minutes and 48 seconds.

• Eclipse start: 9:13 a.m. MT (11:13 a.m. ET)
• “Ring of fire” start: 10:34 a.m. MT (12:34 p.m. ET)

The space agency will also be broadcasting a live feed of three rocket launches that are part of its Atmospheric Perturbations around the Eclipse Path (APEP) mission to study how Earth’s ionosphere responds to a sudden drop in sunlight. You might want to cue that one up in a different browser window alongside the eclipse, or set up picture-in-picture on your device.

Whatever you do, just know that your scheduling calculations and technological machinations are probably way less complicated than all the math scientists do to predict the paths of future eclipses.

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The 2018 winner of PopSci’s annual Best of What’s New continues to impress. NASA’s Parker Solar Probe is still edging closer to the sun than any other spacecraft has ever achieved, and it’s setting new speed records in the process. According to a recent status update from the space agency, the Parker Solar Probe has broken its own record (again) for the fastest thing ever made by human hands—at an astounding clip of 394,736 mph.

The newest milestone comes thanks to a previous gravity-assist flyby from Venus, and occurred on September 27 at the midway point of the probe’s 17th “solar encounter” that lasted until October 3. As ScienceAlert also noted on October 9, the Parker Solar Probe’s speed would hypothetically allow an airplane to circumnavigate Earth about 15 times per hour, or skip between New York City and Los Angeles in barely 20 seconds. Not that any passengers could survive such a journey, but it remains impressive.

[Related: The fastest human-made object vaporizes space dust on contact.]

The latest pass-by also set its newest record for proximity, at just 4.51 million miles from the sun’s plasma “surface.” In order not to vaporize from temperatures as high as nearly 2,500 degrees Fahrenheit, the Parker Solar Probe is outfitted with a 4.5-inch-thick carbon-composite shield to protect its sensitive instruments. These tools are measuring and imaging the sun’s surface to further researchers’ understanding of solar winds’ origins and evolution, as well as helping to forecast environmental changes in space that could affect life back on Earth. Last month, for example, the probe raced through one of the most intense coronal mass ejections (CMEs) ever observed. In doing so, the craft helped prove a two-decade-old theory that CMEs interact with interplanetary dust, which will improve experts’ abilities in space weather forecasting.

Despite its punishing journey, NASA reports the Parker Solar Probe remains in good health with “all systems operating normally.” Despite its numerous records, the probe is far from finished with its mission; there are still seven more solar pass-bys scheduled through 2024. At that point (well within Mercury’s orbit), the Parker Solar Probe will finally succumb to the sun’s extreme effects and vaporize into the solar winds— “sort of a poetic ending,” as one mission researcher told PopSci in 2021.

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On October 14, the Western Hemisphere will witness an annular solar eclipse. The moon will be too small and far away in our view to totally block out the sun’s disc. Instead, it will blot out its center, leaving a ring at the edges. The best locations to view that ring of fire in the sky will be along a path that cuts through Oregon, Texas, Central America, Colombia, and finally northern Brazil. You might decide to visit Albuquerque, New Mexico, where you’ll experience exactly 4 minutes and 48 seconds of an annular eclipse.

And if you’re seeking a true total eclipse, you only have to wait another six months. On April 8, 2024, at 2:10 p.m. Eastern (12:10 p.m. local time), Mazatlan, Mexico will become the first city in North America to see most of the sun vanish in shadow. The path of totality then arcs through Dallas and Indianapolis into Montréal, New Brunswick, and Newfoundland in Canada. We know all of these precise details—and more—thanks to our knowledge of where the moon and sun are situated in the sky at any given moment.

In fact, we can predict and map eclipses farther into the future, even centuries from now. Because they know the precise positions of the moon and the sun and how they shift over time, scientists can project the moon’s shadow onto Earth’s globe. And with cutting-edge computers, it’s possible to chart eclipse paths down to a range of a few feet.

A solar eclipse needs three things. It results when the moon blocks the sun’s light from our vantage point on Earth. So to predict an eclipse, you must know where and how the sun, moon, and Earth move in relation to each other. This isn’t quite as elementary as it may seem, because the solar system isn’t flat. The moon’s orbit slants about 5 degrees in relation to the sun’s path, which astronomers call the ecliptic. While our satellite passes between Earth and the sun around once a month—which we call a new moon—the two rarely seem to cross paths.

Solar eclipses can only occur when the moon is at one of the two points where the moon’s orbit crosses the ecliptic, known as a node. If the moon is new at this crossing, the result is a solar eclipse.

In centuries past, trying to predict eclipses meant predicting minute details of finicky orbits. But as astronomers learned more about how celestial objects moved, they began tabulating what they call ephemerides: predictions of where the moon, sun, and planets will be in the sky. Ephemerides are still the key to eclipse prediction.

[Related: Make a classic pinhole camera to watch the upcoming solar eclipse]

“All you need is the ephemeris data…you don’t have to actually track the orbit,” says C. Alex Young, a solar physicist at NASA’s Goddard Space Flight Center.

With ephemeris data, astronomers can pinpoint dates and times when the moon and sun cross paths. Once you know that date, mapping an eclipse is relatively straightforward. Ephemerides let scientists project the moon’s shadow onto Earth’s sphere; with 19th-century mathematics, they can calculate the shape and latitude of two features of that shadow, the umbra and penumbra. Then, by knowing what time it is and where Earth is angled in its rotation, it’s possible to determine the longitudes. Putting these together produces an eclipse map.

In the past, astronomers printed the ephemerides in almanacs, long tomes filled with page after page of coordinate tables. Just as all of astronomy has advanced into an era of computers, so have ephemerides. Scientists today mathematically model the paths of the moon, sun, planets, other moons, asteroids, and much more.

NASA’s Jet Propulsion Laboratory (JPL) regularly publishes a new compendium of celestial locations every few years. The most recent edition, 2021’s DE440, accounts for details like the moon’s core and mantle sloshing around and slowing its rotation. “Generally speaking, we know where the moon is from the Earth to about a meter, maybe a couple of meters,” says Ryan Park, an engineer at JPL. “We typically know where the sun is to maybe a couple hundred meters, maybe 300 meters.”

[Related: How to look at the eclipse without damaging your eyes]

Ephemerides serve other purposes, especially when planning spaceflight missions. But it’s largely due to more sophisticated ephemeris data that we can now reliably predict the motions of the moon for the centuries ahead. In fact, you can find detailed maps of solar eclipses nearly a millennium in the future. (If you’re lucky enough to be in Seattle on April 23, 2563 or in Amsterdam on September 7, 2974, prepare for total eclipse day.)

But these maps, like most eclipse maps, show the path of totality or annularity as a smooth line crossing Earth’s surface. That isn’t an accurate representation. “This was designed for pencil and paper calculation, so it makes a lot of simplifying assumptions that are just a tiny bit wrong,” says Ernie Wright, who makes eclipse maps for NASA Goddard, “for instance that the moon is a perfectly smooth sphere.”

Both the moon and Earth are jagged at the edge. Earth’s terrain can block some views of the sun, and the moon has its own patchwork of mountains and valleys. In fact, sunbeams passing through lunar vales create the Baily’s beads and “diamond ring” often seen at an eclipse’s edge. “We now have detailed terrain information of these mountains from the Lunar Reconnaissance Orbiter,” Young says.

Wright has helped devise a new way of mapmaking that swaps the Victorian-age mathematics out for modern computer graphics. His method turns Earth’s surface into a map of pixels, each one with different latitude, longitude, and elevation, with the sun and moon in the sky above. Then, the method calculates which pixels see which parts of the moon block which parts of the sun. 

“You then make a whole sequence of maps at, say, one-second intervals for the duration of the eclipse,” Wright says. “You end up with a frame sequence that you can put together to make a movie of the shadow.” This new technique—only possible with modern computers and ultraprecise ephemerides—may allow us to make eclipse maps that clearly show whether you can see an eclipse from, say, your house. 

“I think that’s going to provide a whole new set of maps in the future that are going to be much more accurate,” says Young. “It’s going to be pretty exciting.”

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It’s a well-known fact that staring at the sun is… not the best idea. In the same way that the sun can burn your skin, our home star can overwhelm your peepers with UV rays and literally scorch your retina.

That is a huge bummer, especially because watching a solar eclipse (when the moon covers the sun) is an incredibly cool experience. Thankfully, there are several ways to watch an eclipse without risking your vision, and one of them is building a pinhole camera out of a box, a piece of aluminum foil, and lots of tape. This is an easy and incredibly versatile project, and you can turn it into a permanent camera obscura when you’re done watching the eclipse. 

How to make a pinhole camera

1. Light-proof your box. Leaving one side open, use duct tape or electrical tape to seal the box and prevent any light rays from sneaking in. Pay special attention to the corners and wherever two pieces of cardboard meet. The pinhole will only allow a few rays of light into your box, so the projection of the sun will be dim. That means the darker your camera, the easier it will be to see the image.

As we said, this project is versatile. You can use a wide range of box sizes to make your pinhole camera, but cereal and shoe boxes work exceptionally well. We used the 15-by7 ½-by-5 ½-inch box that carried our neighbor’s latest online shopping spurt. 

Likewise, duct tape and electrical tape are the best choices to light-proof your box, but you can use any tape that will block light—dark washi tape or masking tape will also do the trick. Just keep in mind that you may have to apply multiple layers to achieve total darkness inside your box. 

[Related: A ‘ring of fire’ eclipse and Hunter’s Moon will bring lunar drama to October’s skies]

• Pro tip: Check your work by holding your box up to a light and looking inside. If you still see some shine coming through, apply another layer of tape. 

2. Determine your pinhole’s location and cover the inside of the opposite face with white paper. Measure one of the smallest sides of the box, cut a piece of white paper to the same size, and tape or glue it to the inside of the corresponding face. It doesn’t have to be perfect—as long as most of the side is covered, you’ll be good to go. Just make sure that the paper doesn’t have any wrinkles or folds, as they may distort the image of the sun. 

3. Measure the openings for the pinhole and the viewer. On the side opposite the one you covered with white paper, use your ruler and a pencil to measure two openings. The pinhole opening will be located in the upper left corner (about half an inch from the edges) and will be 2-by-2 inches (we’ll make it smaller later). 

The viewing opening will be located in the upper right corner of the box, half an inch from the top edge and an inch from the right edge of the box. This opening will be smaller—only 1 inch square.

4. Cut the openings. Using a box cutter or scissors, cut out the openings you drew. 

• Pro tip: If the openings end up being too big, don’t sweat it—you can always adjust their size with tape. 

5. Close and seal the box. Use your newly cut openings to make sure there are no other places where light might be sneaking in. Pay special attention to the corners of the box above and below your openings. Cover all the places where pieces of cardboard meet with tape. 

6. Cover the larger opening with aluminum foil. Cut a smooth 2 ½-by-2 ½-inch piece of aluminum foil. With the dull side facing you, carefully cover the big opening with the metallic sheet and tape it in place. Make sure you secure it tightly so no light can get into the box.  

• Pro tip: To smooth out any creases, softly rub the top of any fingernail over the foil in a small, circular motion. 

7.  Use the thumbtack to poke a hole in the foil. Find the rough center of the 2-by-2-inch square under the aluminum sheet and gently push the tack through before pulling it back out—you want a clean, round hole. If you don’t have a thumbtack, you can use the tip of a toothpick or an embroidery needle. Just make sure that whatever you’re using has a point (it’ll make a neater hole) and that it’s approximately 0.2 millimeters wide. 

• Note: The width of your pinhole will determine how much light gets into the box. Too much light and the image will be blurry. If that’s the case, don’t worry—just replace the foil and try making a smaller pinhole. 

8. Put your pinhole camera to the test. Stand with your back facing the sun and look into the box through the viewport. Use your hands to block out as much light as possible and move around until you find the angle where sunlight enters through the pinhole. When this happens, you should see a small projection of the shape of the sun on the white paper you pasted inside the box. 

[Related: Total eclipses aren’t that rare—and you’ve probably missed a bunch of them]

Keep in mind that the weather is crucial in determining the quality of the image you’ll see inside your pinhole camera, and whether you can see the eclipse at all. The October 14 eclipse, in particular, will be annular, so the moon will be smaller than the sun and clouds, rain, or other inclement weather will make it hard to see the event, explains Franck Marchis, a SETI Institute astronomer and the chief scientific officer of Unistellar, a company that manufactures smart telescopes.

How a pinhole camera works

Images are light. Everything we see we perceive because there’s light bouncing off of it, beaming directly through our pupils and into our eyes. All cameras, including the humble pinhole camera you just made, operate under this basic principle. The better they filter the light, the sharper the resulting image will be. 

The sun, of course, is the ultimate light source. On a sunny day, rays from the star travel to Earth and bounce off of every surface they reach. This is a lot of light coming from all directions, so if we want to see only a small portion of the sun’s rays, we have to focus those rays and filter out the rest. That’s why the pinhole in your camera is so tiny or, in more technical terms, why its aperture is so narrow—it only lets a small amount of light into the box, just enough so you can see only a dim projection of the sun when you point the pinhole directly at it. 

The dimness of the image is not ideal, but it’s the tradeoff we make for sharpness—too much light results in a blurry, out-of-focus picture. This is important during a solar eclipse, as filtering the light will allow you to see the round shape of the sun become a crescent or a ring as the moon moves in and gradually blocks the sunlight. 

When the eclipse is over, use a skewer to widen your camera’s pinhole. When you look inside, you won’t only be able to see the sun, but a slightly brighter and inverted image of your surroundings. A bigger pinhole turns your box into a camera obscura, allowing more light in and projecting an image of the objects around you.  

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This month, millions of Americans will have a chance to watch an annular eclipse, also known as a “ring of fire” for the scorching halo the sun forms around the moon. If you’re one of them, be careful: looking directly at a solar eclipse without eye protection can permanently damage your vision.

It doesn’t matter if our rocky satellite is blocking all or some of our nearest star—the sun is still an incredibly bright source of light. Don’t risk your eyesight for a quick glimpse or even a once-in-a-lifetime event. Thankfully, it’s pretty easy to protect your eyes while watching an eclipse..

What happens if you look at a solar eclipse

We are able to see thanks to photoreceptors. These cells, also known as rods and cones, are located at the backs of our eyes, and convert the light reflected by the world around us into electrical impulses that our brain interprets as the image we see. But when strong light, like that from the sun, hits our eyes, a series of chemical reactions occur that damage and often destroy these rods and cones. This is known as solar retinopathy, and can make our eyesight blurry. Sometimes, if the damage is too great in one area, you can lose sight completely.

[Related: Every sunset ends with a green flash. Why is it so hard to see?]

On a typical sunny day, you almost never have to worry about solar retinopathy. That’s because our eyes have natural mechanisms that ensure too much light doesn’t get in. When it’s really bright outside, our pupils get super tiny, reducing the amount of sunlight that can hit your photoreceptors. But when you stare directly at the sun, your pupils’ shrinking power isn’t enough to protect your peepers.

This is where your eyes’ second defense mechanism comes into play. When we look at something bright, we tend to blink. This is known as the corneal or blink reflex, and it  prevents us from staring at anything too damagingly bright. 

Just before a solar eclipse has reached its totality, the moon is partially blocking the sun, making it a lot easier for us to look up at the star without blinking. But that doesn’t mean you should—even that tiny sliver of sunlight is too intense for our sensitive photoreceptors.

[Related: Total eclipses aren’t that rare—and you’ve probably missed a bunch of them]

Unfortunately, if you practice unprotected sun-gazing, you probably won’t know the effects of your actions until the next morning, when the damage to your photoreceptors has kicked in.

And while solar retinopathy is extremely rare, it is by no means unheard of. If you search the term in medical journals, you’ll find case reports after almost every popular solar eclipse. Let’s try really hard to do better this time, eyeball-havers.

How to safely watch a solar eclipse

Watching the eclipse with your own two eyes is easy: just wear legitimate eclipse sunglasses. These are crucial, as they will block the sun’s rays enough for you to safely see the eclipse without burning your eyes out.

And if you don’t have eclipse glasses, you can still enjoy the view, albeit not directly. Try whipping up your own eclipse projector or a DIY pinhole camera so you can enjoy the view without having to book an emergency visit to the eye doctor.

This story has been updated. It was originally published in 2017.

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Solar sails that leverage the sun’s photonic rays for “wind” are no longer the stuff of science fiction—in fact, the Planetary Society’s LightSail 2 practical demonstration was deemed a Grand Award Winner for PopSci’s Best of What’s New in 2019. And while countless projects continue to explore what solar sails could hold for the future of space travel, a new study demonstrates just how promising the technology could be for excursions to Earth’s nearest planetary neighbor, and beyond.

According to a paper recently submitted to the journal Acta Astronautica, detailed computer simulations show tiny, incredibly lightweight solar sails made with aerographite could travel to Mars in just 26 days—compare that to conventional rocketry time estimates of between 7-to-9 months. Meanwhile, a journey to the heliopause (the demarcation line for interstellar space where the sun’s magnetic forces cease to influence objects) could take between 4.2 and 5.3 years. For comparison, the Voyager 1 and Voyager 2 space probes took a respective 35 and 41 years to reach the same boundary.

[Related: This novel solar sail could make it easier for NASA to stare into the sun.]

The key to such speedy trips is the 1 kg solar sails’ 720g of aerographite—an ultra-lightweight material with four times less density than most solar sail designs’ Mylar components. The major caveat to these simulations is that they involved an extremely miniscule payload weight, something that will most often not be the case for major interplanetary and interstellar journeys.

“Solar sail propulsion has the potential for rapid delivery of small payloads (sub-kilogram) throughout the solar system,” René Heller, an astrophysicist at the Max Planck Institute for Solar System Research and study co-author, explained to Universe Today earlier this month. “Compared to conventional chemical propulsion, which can bring hundreds of tons of payload to low-Earth orbit and deliver a large fraction of that to the Moon, Mars, and beyond, this sounds ridiculously small. But the key value of solar sail technology is speed.”

Another issue still that still needs addressing is deceleration methods needed upon actually reaching a destination. Although aerocapture—using a planet’s atmosphere to reduce velocity—is a possible option, researchers concede more investigation will be needed to determine the best, most efficient way to actually stop at a solar sail-equipped spacecraft’s intended endpoint. Regardless, the study only adds even more wind in the sails (so to speak) for the impressive interstellar travel method.

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Every year or two, the solar system lines up just right, with the moon casting a shadow over part of Earth’s surface and blocking out the sun—a solar eclipse. In 2017, people across the United States flocked to see the “Great American Total Eclipse”, which was the first one visible in the continental states since 1979. Now, eclipse chasers and citizen scientists across North America are getting ready for the next big events: an annular eclipse on October 14, 2023 and a total eclipse on April 8, 2024. This will be the last eclipse visible in the continental US until August 2045, more than two decades away. 

People love eclipses for the novelty—how cool it is to see the sun disappear in the day. But these phenomena are both showstoppers and opportunities: a group of radio astronomers and citizen scientists called Radio JOVE is aiming to capitalize on the upcoming eclipses for science, part of NASA’s “Helio Big Year.”

Radio JOVE “initially started as an education and outreach project to help students, teachers, and the general public get involved in science,” explains project co-founder Chuck Higgins, an astronomer at Middle Tennessee State University. The project has been running since the late 1990s, when it began at NASA’s Goddard Space Flight Center. “We now focus on science and try to inspire people to become citizen scientists.” 

As its name suggests, Radio JOVE originally focused on the Jovian planet, Jupiter. “Serendipitously, it turns out that the same radio wavelengths we use for observing Jupiter are also useful for observing the sun,” says Thomas Ashcraft, a citizen scientist from New Mexico who has been observing with Radio JOVE since 2001. After the 2017 Great American Eclipse, its members became more involved with heliophysics, the study of the sun.

[Related: Total eclipses aren’t that rare—and you’ve probably missed a bunch of them]

As energy spews from the sun and travels to Earth, it interacts with our planet’s atmosphere; in particular, the sun’s rays create a layer of ionized particles, known as the ionosphere. Any radio waves coming from the sun have to pass through these particles above us. Communication technology takes advantage of this layer, bouncing radio waves off it to travel long distances.

The ionosphere’s plasma changes a lot between day and night. When the sun shines on this layer, particles break into ions. When the sun is absent, those ions calm down. During eclipses, when most of the sun’s light is blocked, similar changes happen in the short term change. By measuring those fluctuations precisely with a fleet of amateur observers, Radio JOVE hopes to improve our understanding of the ionosphere.

To do so, Radio JOVE is equipping citizen scientists across the country with small radio receivers and training them to observe radio waves from Earth’s ionosphere. The project offers some-assembly-required starter kits for around $200, and a whole team of experts and experienced observers are around to support new volunteers. 

[Related: The best US parks for eclipse chasers to see October’s annularity]

Right now, they’re prepping participants for a full day of observing during the October annular eclipse. Project members are already gathering data to have a baseline of the sun’s influence on a normal day, which they’ll compare to the upcoming eclipse data. And this is only a small taste before the big event: next year’s total eclipse. “The 2023 annular eclipse will be used as a training, learning, and testing experience in an effort to achieve the highest quality data for the 2024 total eclipse,” Higgins wrote in a summary for an American Geophysical Union conference.

Citizen science projects such as Radio JOVE not only collect valuable data, but they also involve a new crowd in NASA’s scientific community. Anyone interested in science can join in, and if Radio JOVE doesn’t suit your interests, NASA has a long list of other opportunities. For example, if you’re a ham radio operator, you can get involved with HamSCI, which also plans to observe the upcoming eclipse.

“NASA’s Radio JOVE Citizen Science Project allows me to further explore my lifelong interest in astronomy,” said John Cox, a Radio JOVE citizen scientist from South Carolina, in a NASA press release. “A whole new portion of the electromagnetic spectrum is now open to me.”

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On October 14, the moon will cruise between Earth and the sun during an annular solar eclipse, casting an immense shadow on our planet. It will be a sight to behold, though you’ll want to wear protective glasses or glimpse it indirectly to avoid frying your eyeballs. Unlike 2017’s total eclipse, the sun won’t vanish completely; instead, the moon will be positioned far enough from our planet to leave the star’s brilliant edges visible. The result is a “ring of fire,” as though the moon has been outlined with a blowtorch. Every continental state will have at least a partial view of this event, but spotting this celestial circle could be well worth the travel. 

The eclipse’s 125-mile-wide path of annularity begins in the US in Oregon at 12:13 p.m. Eastern (9:13 a.m. Pacific). It will loom over the country until it leaves Texas at 1:03 p.m. (12:03 Central), continuing its southeastward journey to Central and South America. The best viewing conditions will be in places with low fog and high aridity, like Nevada and Utah, the two driest states in the country. “The place with the lowest chance of cloud cover is Albuquerque, New Mexico—but most of the path of annularity looks pretty good,” says University of Texas at San Antonio astrophysics professor Angela Speck, who co-chairs the American Astronomical Society’s Solar Eclipse Task Force.  

Oregon

The first US national park that the eclipse will pass over is Crater Lake, where water has filled a collapsed volcano, Mount Mazama. All of the park is in the annularity’s path, so prepare for crowds as well as limited parking and lodging.

Other Oregon parks in the path:
Shore Acres State Park

[Related: We’ve been predicting eclipses for over 2,000 years. Here’s how.]

California

Bat-filled caves, battlefields, and basaltic flows make up Lava Beds National Monument, a desert landscape that is the product of thousands of years of volcanic activity. Only the northeast sliver of this California park is directly in the annularity’s path, but the section just outside it may be a good vantage for another fascinating feature of the eclipse: Baily’s beads, short-lived bright dots caused when sunbeams stream through the crags and valleys of the lunar surface.

Nevada

The southern edge of the US path of annularity cuts through Great Basin National Park, where park staff will be available to guide viewers, according to the National Park Service. The agency also notes that, while the park tends to be less busy in October, eclipse watchers should be prepared for the event to bring out crowds.

Utah

Parsons-Bernstein ordered 20,000 eclipse glasses that will be distributed across Utah’s state parks on a first come, first serve basis. “In the entire state, there’s no less than 83 percent view of the annularity,” she says. But several areas are “dead-on 100 percent,” including 13 parks that are directly in the eclipse’s path. One of those is Goblin Valley State Park, which boasts rocky scenery so otherworldly that the movie Galaxy Quest used it as an alien planet.

Other Utah parks in the path:
Bryce Canyon National Park
Capitol Reef National Park
Canyonlands National Park
Escalante Petrified Forest State Park
Glen Canyon National Recreation Area
Goosenecks State Park
Kodachrome Basin State Park
Hovenweep National Monument
Natural Bridges National Monument
Rainbow Bridge National Monument
Territorial Statehouse State Park Museum

Arizona 

The moon’s shadow will zip into Arizona at speeds of around 3,150 mph, slowing to 2,626 mph as it leaves. It will pass through Navajo National Monument, where, for hundreds of years, Hopi, Navajo, and other Native Americans lived in the canyons. However, visitors to the Hopi Reservation and Navajo Nation should be aware that, in some traditions, eclipses are sacred times to pray or meditate indoors. 

Other Arizona parks in the path:
Canyon De Chelly National Monument

[Related: 7 US parks where you can get stunning nightsky views]

Colorado

Celebrating its remarkable Ancestral Pueblo cliff settlements, Mesa Verde National Park became a UNESCO World Heritage Site in 1978. Go for the eclipse, but stick around after nightfall on campgrounds and scenic overlooks: The park has one of the darkest skies in the continental US, and boasts stellar views of the Milky Way.

Other Colorado parks in the path:
Yucca House National Monument

New Mexico

The Manhattan Project National Historical Park at Los Alamos was once the secret city where physicists developed the atomic bomb. Now, certain areas are open to the public (many of the buildings are within an area secured by the Energy Department that’s only occasionally available by guided tour). But hikers can take the trail loop on Kwage Mesa, which will offer views of the annularity.

Other New Mexico parks in the path:
Aztec Ruins National Monument
Bandelier National Monument
Chaco Culture National Historical Park
Pecos National Historical Park
Petroglyph National Monument
Rio Grande Nature Center State Park
Salinas Pueblo Mission National Monument
Valles Caldera National Preserve

Texas

As the eclipse falls over the Lone Star State, it will darken 17 state parks as well as San Antonio Missions National Historical Park. Just after noon, it will depart the US for the Gulf of Mexico, but not before touching one last bit of public American land: the Padre Island National Seashore, which is just a quick drive from Corpus Christi and famous for its unique, biodiverse mudflats.

Other Texas parks in the path:
Big Spring State Park
Choke Canyon State Park
Goose Island State Park
Kickapoo Cavern State Park
Lake Corpus Christi State Park
Mustang Island State Park

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An unexpected and astonishing find located more than 2.5 million light-years from Earth took top honors at the Royal Observatory Greenwich’s Astronomy Photographer of the Year awards this week. Amateur astronomers Marcel Drechsler, Xavier Strottner, and Yann Sainty captured an image of a massive plasma arc near the Andromeda Galaxy, a discovery that has resulted in scientists looking closer into the giant gas cloud.

“This astrophoto is as spectacular as [it is] valuable,” judge and astrophotographer László Francsics said in a press release. “It not only presents Andromeda in a new way, but also raises the quality of astrophotography to a higher level.”

[Related: How to get a great nightsky shot]

While “Andromeda, Unexpected” captured the prestigious overall winner title, other category winners also dazzled with photos of dancing auroras, neon sprites raining down from the night’s sky, and stunning far-off nebulas that might make you feel like a tiny earthling floating through space.

Sit back and scroll in awe at all the category winners, runners-up, and highly commended images from the 2023 Royal Observatory Greenwich’s Astronomy Photographer of the Year honorees.

Galaxy

Overall winner: Andromeda, Unexpected

Runner-Up: The Eyes Galaxies

Highly Commended: Neighbors

Aurora

Winner: Brushstroke

Runner-up: Circle of Light

Highly Commended: Fire on the Horizon

Our Moon

Winner: Mars-Set

Runner-Up: Sundown on the Terminator

Highly Commended: Last Full Moon of the Year Featuring a Colourful Corona During a Close Encounter with Mars

Our Sun

Winner: A Sun Question

Runner-Up: Dark Star

Highly Commended: The Great Solar Flare 

People & Space

Winner: Zeila

Runner-Up: A Visit to Tycho

Highly Commended: Close Encounters of The Haslingden Kind

Planets, Comets & Asteroids

Winner: Suspended in a Sunbeam

Runner-Up: Jupiter Close to Opposition

Highly Commended: Uranus with Umbriel, Ariel, Miranda, Oberon and Titania

Skyscapes

Winner: Grand Cosmic Fireworks

Runner-Up: Celestial Equator Above First World War Trench Memorial

Highly Commended: Noctilucent Night

Stars & Nebulae

Winner: New Class of Galactic Nebulae Around the Star YY Hya

Runner-Up: LDN 1448 et al.

Highly Commended: The Dark Wolf – Fenrir

The Sir Patrick Moore Prize for Best Newcomer

Winner: Sh2-132: Blinded by the Light

Young Astronomy Photographer of the Year

Winner: The Running Chicken Nebula

Runner-Up: Blue Spirit Drifting in the Clouds

Highly Commended: Lunar Occultation of Mars

Highly Commended: Roses Blooming in the Dark: NGC 2337

Highly Commended: Moon at Nightfall

Annie Maunder Prize for Image Innovation

Winner: Black Echo

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Update (September 5, 2023): India successfully launched its Aditya-L1 solar observatory on September 2 at 2:20 am EST. It is expected to arrive at its first destination between the Earth and the sun in January 2024.

On August 23, the Indian Space Research Organization (ISRO) pulled off the Chandrayaan-3 mission, depositing the Vikram lander and Pragyan rover near the lunar South Pole. India is now the fourth nation to land on the moon—following Russia, the US and China— and the first to land near the lunar South Pole, where the rover has already detected sulfur and oxygen in the moon’s soil. Fresh off of this success, ISRO already has another mission underway, and its next target is something much bigger—the sun.

The ISRO’s Aditya-L1 spacecraft, armed with an array of sensors for studying solar physics, is scheduled to launch around 2 a.m. Eastern on September 2, atop a PSLV-C57 rocket from the Satish Dhawan Space Center in Sriharikota, in southeast India.

Aditya-L1 will begin a four-month journey to a special point in space. About 932,000 miles away is the sun-Earth L1 Lagrangian, an area where the gravity of Earth and the sun cancel out. By entering into an orbit around L1, the spacecraft can maintain a constant position relative to Earth as it orbits around the sun. It shares this maneuver with the NASA-ESA Solar and Heliospheric Observatory, or SOHO, which has been in the sun-observation business since 1996. If it reaches the L1 orbit, Aditya-L1 will join SOHO, NASA’s Parker Solar Probe, ESA’s Solar orbiter, and a handful of other spacecraft dedicated to studying the closest star to Earth. 

“This mission has instrumentation that captures a little bit of everything that all of these missions have already done, but that doesn’t mean we’re going to replicate science,” says Maria Weber, a solar astrophysicist at Delta State University in Mississippi, who also runs the state’s only planetarium at that campus. ”We’re getting more information and more data now at another time, a new time in the solar cycle, that previous missions haven’t been able to capture for us.” The sun undergoes 11-year patterns of waxing and waning magnetic activity, and the current solar cycle is expected to peak in 2025, corresponding with more sunspots and solar eruptions.

Aditya-L1 will carry seven scientific payloads, including four remote sensing instruments: a coronagraph, which creates an artificial eclipse for better study of the sun’s corona, an ultraviolet telescope, and high and low X-ray spectrographs, which can help study the temperature variations in parts of the sun. 

[Related: Would a massive shade between Earth and the sun help slow climate change?]

“One thing I’m excited about is the high-energy component,” says Rutgers University radio solar physicist Dale Gary. Aditya-L1 will be able to study high-energy x-rays associated with solar flare and other activity in ways that SOHO cannot. And L1 is a good position for that sort of study, he says, since there is a more stable background of radiation against which to measure solar X-rays. Past measurements made in Earth orbit had to contend with Van Allen radiation belts. 

Aditya-L1’s ultraviolet telescope will also be unique, Gary says. It measures ultraviolet light, which has shorter wavelengths than visible light; the shortest or extreme UV light, near the X-ray spectrum, has already been measured by SOHO, but Aditya will capture the longer UV wavelengths.

That could allow Aditya-L1 to study parts of the sun’s atmosphere that have been somewhat neglected, Gary says, such as the transition region between the chromosphere, an area about 250 miles about the sun’s surface, and the corona, the outermost layer of the sun that begins around 1,300 miles above the solar surface and extends, tenuously, out through the solar system. 

Although ground-based telescopes can take some measurements similar to Aditya’s, the spacecraft is also kitted out with “in situ” instruments, which measure features of the sun that can only be observed while in space. “It’s taking measurements of magnetic fields right where it’s sitting, and it’s taking measurements of the solar wind particles,” Weber says. 

Like all solar physics missions, Aditya-L1 will inevitably serve two overall purposes. The first is to better understand how the sun—and other stars— work. The second is to help predict that behavior, particularly solar flares and coronal mass ejections. Those eruptions of charged particles and magnetic fields can impact Earth’s atmosphere and pose risks to satellites and astronauts. In March 2022, a geomagnetic storm caused by solar radiation caused Earth’s atmosphere to swell, knocking 40 newly launched SpaceX Starling satellites to fall out of orbit. 

“We live with this star and so, ultimately, we want to be able to predict its behavior,” Weber says. “We’re getting better and better at that all the time, but the only way we can predict its behavior, is to learn as much as we can even more about it.”

[Related: Why is space cold if the sun is hot?]

Aside from Aditya-L1’s scientific mission, its success will mark another feather in the cap of ISRO, another step in that space agency’s hard work to make India a space power, according to Wendy Whitman Cobb a space policy expert and instructor at the US Air Force School of Advanced Air and Space Studies (who was commenting on her own behalf, not for the US government). 

“India has had some pretty expansive plans for the past two decades,” she says. “A lot of countries say they’re going to do something, but I think India is that rare example of a country who’s actually doing it.”

Of course, space is hard. ISRO’s first lunar landing attempt with Chandrayaan-2, in 2019, was a failure, and there’s no guarantee Aditya-L1 will make it to L1. “It’s a technical achievement to go into the correct orbit when you get there,” Gary says. “There’s a learning curve. It would be very exciting if they accomplish their goals and get everything turned on correctly.”

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On the one hand, the sun provides life-giving heat and light. On the other, it spews an incessant stream of potentially harmful charged particles. These particles form the solar wind, and it is no less formidable than our star’s other products. Without Earth’s magnetic field to shield our planet’s surface, we would constantly face a bombardment of ionizing radiation.

But astronomers have never been completely certain where those particles come from or how they travel into interplanetary space. Now, they’ve found a promising clue. Using ESA’s Solar Orbiter spacecraft, researchers have found miniature jets that seem to channel particles up through holes in the sun’s corona and away from the star. These jets might combine to blow the solar wind, a group of astronomers suggests in a paper published in the journal Science on Thursday.

The corona, a star’s outermost layer, is a sheath of undulating plasma. It is almost always hidden in visible light, although it’s thousands of times hotter than the layers below. We might only see this outer layer during a solar eclipse, when the moon blots out the rest of the sun. 

But the corona is not one even layer. Imaging the sun in ultraviolet reveals shifting dark swatches: regions where the corona’s plasma is cooler and less dense. Astronomers call these areas coronal holes.

[Related: Why is space cold if the sun is hot?]

Coronal holes also seem to resculpt the sun’s powerful, endlessly changing magnetic field. In these parts, lines that guide the sun’s magnetic field seem to blow outward. “Usually, magnetic fields loop back to the solar surface, but in these open field regions the lines of force stretch into interplanetary space,” says Lakshmi Pradeep Chitta, an astronomer at the Max Planck Institute for Solar System Research in Göttingen, Germany, and one of the paper’s authors.

It’s also within coronal holes that the sun’s magnetic field lines can knot about themselves. When that happens, the magnetic field realigns and reconnects, creating fierce electrical surges. Those energetic outbursts siphon matter from deeper layers of the sun and toss them away in jets that can stretch more than a thousand miles across. Astronomers had long suspected that these jets fuel the solar wind, but didn’t know if these jets could provide enough particles to fill the solar wind we observe.

Sun-watching spacecraft like Yohkoh and SOHO have been able to see jets since the 1990s. But astronomers say that none have the sightseeing abilities of Solar Orbiter, which launched in 2020. At its closest approach, Solar Orbiter dips closer to the sun than Mercury.

“Solar Orbiter has the advantage of being located close to the sun, so it can detect smaller and fainter jets,” says Yi-Ming Wang, an astronomer at the US Naval Research Laboratory, who was not an author of the paper.

In March 2022, Chitta and his colleagues focused one of Solar Orbiter’s ultraviolet cameras upon a coronal hole situated near the sun’s south pole. When they did, they glimpsed a type of miniature jet never before seen by humans. Each of these tiny jets carried around one-trillionth the energy of a full-size version. The authors dubbed these “picoflare jets,” dipping into SI system prefixes.

These adorable-sounding surges don’t stick around. Each fleeting picoflare jet lasts about a minute. But this is still the sun—a place of immense power. A single solar picojet might create enough energy to power a small city for a year.

[Related: How a sun shade tied to an asteroid could cool Earth]

The authors scoured only one small part of the sun, but they saw picoflare jets in every corner they looked. It’s likely they cover much of the sun’s surface. Myriads of miniature jets, then, might combine into a large-scale process that transfers charged particles away from the star and out toward the planets.

“We suggest that these tiny picoflare jets could actually be a major source of mass and energy to sustain the solar wind,” Chitta says.

In years past, many astronomers thought of the solar wind as a steady flow, streaming away from the sun at a constant rate. But, if surging picoflare jets drive the solar wind, then the phenomenon might actually be ragged, uneven, and constantly in flux. Picoflare jets may not be the only source of the solar wind, but if Chitta and colleagues are correct, they’re at least a significant contributor.

Fortunately, scientists in a few years’ time will have plenty of additional tools to peer into the sun. Alongside the Solar Orbiter—and future sun-seeing spacecraft, such as the Japanese-led SOLAR-C—they’ll have more powerful solar magnetograms, instruments that allow them to directly measure the sun’s magnetic field from places like Southern California and Maui, able to track the magnetic fluctuations powering the sun’s jets from right here on Earth.

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Some of the most exotic solutions to climate change are the various forms of geoengineering. Such proposals aim to reduce global warming by shrinking the amount of solar radiation that reaches Earth’s surface—by, say, injecting large amounts of sulfur dioxide or dust into the air to mimic the cooling effect of large volcanic eruptions. Or building catapults to launch lunar dust into orbit around Earth and intercept the sun’s rays in the space near our planet. 

But University of Hawaii cosmologist István Szapudi has an even more far-out idea: place a 372,000-mile-wide sun shade tethered to a captured asteroid between Earth and the sun to reduce the amount of solar radiation reaching our planet by 1.7 percent. His analysis is agnostic to the shade’s shape, though he imagines it could be a circular shade made of triangular segments, able to open or close like flower petals to allow variable amounts of sunlight through. 

“It’s not going to cast a sharp shadow,” Szapudi says. ”Maybe with a telescope you could notice that there is something in front of the sun. But other than that, it would just be that people would notice that the weather is a little bit better.”

He readily admits that this concept would require millions of dollars investment in just preliminary engineering studies to see if it is really possible. “Of course, it’s unrealistic to actually do this, so hopefully, we will slowly give up fossil fuels,” Szapudi says, citing a much more mainstream goal to curb a source of climate change. “But that’s a very long-term process.”

In the meantime, he suggests, maybe the world can consider alternatives to help mitigate the change in climate that occurs from the carbon already in Earth’s atmosphere today. 

Szapudi’s proposal, as described in a paper published on July 31 in the Proceedings of the National Academy of Sciences, would place this massive sun shade at the Sun-Earth Lagrange Point 1, or L1. This is a region of space about 932,000 miles toward the sun from Earth where the gravity of both bodies cancels out, allowing a spacecraft orbiting L1 to maintain a constant position relative to the sun and Earth with minimal maneuvering. The James Webb Space Telescope makes use of the same phenomena at L2, the L1 point’s counterpart 932,000 miles away from Earth in the direction of the outer solar system. 

[Related: How big banks can make real progress against climate change]

Szapudi is not the first to suggest placing a sun shade at L1, but previous proposals ran into problems. Namely, a large sun shade will also act like a solar sail, catching solar radiation that will push the structure out of position at L1. Previous proposals got around this by making the sun shade extremely massive, on the order of 350 million tons, perhaps of metal or asteroid stuff—an utterly unrealistic amount of mass even for a proposal that’s already this far out. 

Szapudi instead proposes connecting it to an asteroid counterweight by tethers up to 1.9 million miles long. Since the sun’s gravity is more potent the further away from L1 and closer to the star you go, the tug of solar gravity on the asteroid will counterbalance the radiation pressure on the sun shade, allowing it to stay in place. 

With such a configuration, Szapudi estimated the shade itself might weigh only 35,000 tons. “That’s something that SpaceX could put up in space” using its current rockets, he says, though it’d take a lot of time and effort. A sun shade could be made even lighter, Szapudi suggests, if made from something like graphene, an extremely light and strong material consisting of atom-thick sheets of carbon atoms arranged in a hexagonal lattice pattern. 

Astronomers would have to identify a suitable near-Earth asteroid for the counterweight through something like the University of Hawaii’s Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), Szapudi says. But once they did, the sun shade could be tethered to the asteroid in its existing orbit and used as a solar sail to divert the space rock toward the L1 point. 

Engineering-wise, the whole idea is extremely speculative, Szapudi emphasizes, relying on technology that is not yet developed, such as materials strong and light enough to serve as the tethers. 

[Related on PopSci+: Cloudy with a chance of cooling the planet]

But it’s also not clear if geoengineering of this sort would actually help mitigate the effects of climate change, or do so without introducing other, unpredictable and negative consequences, according to Rutgers University climatologist Alan Robock. Robock leads the Rutgers Geoengineering Model Intercomparison Project, which uses climate change models to predict the effects of geoengineering interventions.

“What if you start doing it and you say, ‘OK, we figured out that 90 percent of the world is going to be better off, but 10 percent is going to be worse off,” Robock says. “But we don’t know which 10 percent because of randomness in the climate system.”

And some effects are well understood, likely, and not good, he adds. 

“For example, you’d get drought in Africa and Asia, because the summer monsoon is driven by the temperature difference between the land and the ocean in the summer,” Robock says. “If you block out the sun, the land would cool more than the ocean. And so that temperature difference would go down. In the summer monsoon precipitation would be reduced.” 

And if something went wrong with the sun shield, and it stopped blocking the sun suddenly, Earth would warm back up much more rapidly than humans have ever experienced r. 

“That’s called the termination problem,” Robock says, and it’s something that dogs all geoengineering proposals. 

And then there’s also the very human problem of cooperating on what is essentially a species-wide project: building and tuning a sun shade. How do humans agree on how much sun to block, or as Robock puts it, how does the world agree on where to set the planetary thermostat? “Countries like Canada and Russia wouldn’t mind it being a little bit warmer,” he says. “In fact, we’ve calculated their agriculture would improve, but countries in the tropics would want it cooler because sea levels are going up, they’re already drowning.”

Ultimately Robock sees geoengineering projects as potential distractions from reducing emissions today. The best solution to climate change, Robock says—and Szapudi agrees—is to leave fossil fuels in the ground. 

 But Szapudi sees his proposal as a project to help mitigate the lasting effects of emissions that have already taken place. It could be an insurance policy to help turn off the worst effects of global warming that are already baked into the climate—but it only works if we start such a long term research project now. 

As an insurance policy, though, it’d have one expensive premium. “If technology develops the way I hope it would, maybe this is a trillion-dollar project,” Szapudi says. “You would need at least an army of engineers, probably tens of millions of dollars just to explore the concept to enough detail.”

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Update (July 11, 2023, 5:22 pm): An early forecast released by the University of Alaska Fairbanks Geophysical Institute initially indicated that given the right weather, the northern lights may be visible on Thursday July 13 in at least 17 states. The forecast was updated on Monday evening to show that aurora was unlikely to be seen in those initially forecasted regions, but may be visible in regions where they are more commonly seen, namely parts of Alaska and several Canadian provinces. 

“The accuracy of the models to predict the auroral activity depend strongly on the accuracy and number of input measurements of the activity on the sun and the intervening space where the solar wind is flowing and evolving after it leaves the sun. There are only a few satellites and instruments dedicated to collecting these data, so the models typically have a wide range of predictions since the observations are relatively sparse. While large solar storms can be seen leaving the vicinity of the sun, and their direction and speed can be estimated, once they leave the local solar vicinity they cannot be tracked. During this time the solar storms can be slightly diverted or even reduced, and the final impact on Earth’s magnetic field may be different than predicted,” research associate professor Don Hampton, a space physicist at the University of Alaska Fairbanks Geophysical Institute, told PopSci in an email.

This prediction was made several days ahead of time and is based on models that are run by NOAA’s Space Weather Prediction Center. The Geophysical Institute doesn’t make long-term auroral predictions and this more short-term forecast is from the SWPC. (An article on EarthSky has contested the University of Alaska Fairbanks Geophysical Institute’s aurora forecast.)

Only a few satellites and instruments are dedicated to collecting this data, so models generally have a wide range of predictions due to more sparse observations. It’s possible large solar storms can be seen leaving the sun and their speed and direction can be estimated. However, once they leave the vicinity of the sun they can’t be tracked. During this time, solar storms can be slightly moved off course or even reduced which can change the final impact that the solar storm has on Earth’s magnetic field.

Additionally, Lieutenant Bryan R. Brasher from the SWPC said that this initial prediction for moderate geomagnetic storming on Thursday was influenced by the recurrence of a particular coronal hole in the sun. This spot caused higher geomagnetic activity.

“Some features –such as corona holes–can persist for many weeks and so a good starting point for predicting long range behavior is how these features affected the space environment the last time they faced Earth,” Brasher told PopSci in an email. “This was reflected in our weekly 27-day outlook product. As this particular coronal hole rotated back into view however–meaning we could see and analyze it–it was clear that it had diminished and we adjusted our forecast accordingly.”

Brasher added that while the immediate forecast doesn’t necessarily call for aurora activity this week, the Earth is approaching a solar maximum phase in the sun’s roughly 11-year cycle. This period is characterized by heightened solar activity, similar to the storms seen in March and April.

An earlier version of this story follows.

Residents of 17 states could catch a glimpse of the elusive aurora borealis, also known as the northern lights, this Thursday. The predicted rainbow of colors that light up the night sky when solar wind hits the atmosphere is part of a solar cycle that is expected to peak in 2024, and is making the northern lights visible in points further south. 

[Related: We finally know what sparks the Northern Lights.]

The Geophysical Institute at the University of Alaska at Fairbanks has forecast auroral activity on July 12 and 13 parts of in Alaska, Oregon, Washington, Idaho, Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, New York, New Hampshire, Vermont, Indiana, Maine, and Maryland.

The Kp index, or planetary index, ranks auroral activity on a scale from zero up to nine—zero being not very active and nine being bright and active. Thursday’s storm has a forecast for Kp6, according to the Geophysical Institute.

The forecast predicts that on Wednesday, the storm could be highly visible “low on the horizon from Seattle, Des Moines [Iowa], Chicago, Cleveland, Boston, and Halifax [Nova Scotia].”

On Thursday, it could get stronger and may be seen overhead in cities including Minneapolis, Milwaukee, Bay City, Michigan. The lights could be visible on the horizon in Salem, Boise, Cheyenne, Lincoln, Indianapolis, and Annapolis. 

The northern lights occur when the sun’s continuous solar wind and solar storms, specifically those called coronal mass ejections, interact with Earth’s magnetic field. The light show happens very frequently in locales like northern parts of Canada, Alaska, and Scandinavia. Huge bursts of plasma are ejected via this wind, spraying electrons into the magnetic field. These super charged particles then combine with the field and shoot into Earth’s atmosphere, following the path of the magnetic field towards the Earth’s poles. When these particles collide with molecules in the atmosphere, they produce the dazzling colored lights in our sky.

UCLA space science professor Robert McPherron told PopSci in September 2022 that this process is similar to switching off old television sets. “When you turn them on, if you had good hearing, you’d hear a very high pitched whine indicative of a very high frequency” caused by a beam of electrons. And if you turned it off, you’d see a spot right in the center of the screen.”

That glowing spot on the fluorescent screen occurs when a beam of electrons hits it from the inside. “And that’s exactly what the aurora is,” McPherron said. “It is electrons coming down along a magnetic field line, and the screen is the atmosphere.”

[Related: Hold onto your satellites: The sun is about to get a lot stormier.]

The greens, blues, and reds that result come from the electrons as well. As they enter the Earth’s atmosphere, the electrons excite gasses, particularly oxygen and nitrogen. Once the molecules within the oxygen and nitrogen are charged with this energy beyond their normal state, they emit photons as they return back to their baseline levels. Oxygen emits greens and reds, while nitrogen glows blue. 

In April,  the northern lights were visible as far south as Arizona during a huge surge of solar activity. This next storm is the third severe geomagnetic storm since this current solar cycle began in 2019. 

According to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, those hoping to catch a glimpse of the aurora should head away from city lights and that the best viewing times are between 10 PM and 2 AM local time.

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With the summer solstice behind us, it’s true that we are losing tiny bits of sunlight per day.  But that just means the short summer nights are growing a bit longer—all the better to catch exciting things happening this month. Skygazing in July should be pretty comfortable for those in the Northern Hemisphere as temperatures reach their summer highs. Here are some events to look out for and if you happen to get any stellar sky photos, tag us and include #PopSkyGazers.

July 1: Conjunction of Venus and Mars 

Kicking off the first full month of summer with Venus and Mars at making a close approach to one another. The two planets will be visible just after 8 PM EDT on June 30, and will reach their closest approach at 3:09 AM EDT on July 1 as dusk fades into darkness. Both planets will lie roughly within the constellation Leo. 

[Related: We finally know why Venus is absolutely radiant.]

July 3: Full Buck Supermoon

July’s full moon will rise on Monday, July 3 and reach peak illumination at 7:39 AM EDT. The moon will be below the horizon, so skygazers should look towards the southeast after the sunset to watch the Buck Moon rise. 

It is also a supermoon, which means that it will appear bigger than many other full moons this year. It will be 224,895.4 miles away from Earth, and only next month’s Blue Moon will venture closer to Earth this year. According to the Old Farmer’s Almanacs, this is the first of four total supermoons for 2023.

The name Buck Moon refers to the time of year when the antlers of male deer are in full-growth mode. Additional names for July’s full moon include the Blueberry Moon or Miini-giizis in Anishinaabemowin (Ojibwe), the String Bean Moon or Ohyotsheli in Oneida, and the Thunderstorm Moon or Hiyeswa Tiriri Nuti in the Catawba Language.

[Related: ‘Skyglow’ is rapidly diminishing our nightly views of the stars.]

July 7: Venus at its brightest point of the year

The second planet from our sun is already an extremely luminescent planet, but it will be at its brightest point for all of 2023 this month. It’s hard to miss this dazzling planet, so look in the direction of sunset on any clear summer evening beginning on July 7. The lighted portion of the planet, known as the crescent Venus, will cover its greatest area on our sky’s dome. 

July 16-27: Lāhaina Noon

This twice a year event occurs during the months of May and July in the Earth’s tropical region when the sun is directly overhead at around solar noon. At this point, upright objects do not cast shadows. 

According to the Bishop Museum, in English, the word “lāhainā” can be translated as “cruel sun,” and is a reference to severe droughts experienced in that part of the island of Maui in Hawaii. An older term in ʻŌlelo Hawaiʻi is “kau ka lā i ka lolo,” which means “the sun rests upon the brain,” and references both the physical and cultural significance of the event.

July 29-30: Delta Aquarids meteor shower peaks

The lesser known Delta Aquarids is the first of the summer’s annual meteor showers. It starts on July 18, but is predicted to peak on July 29 and 30. However, if you miss it, don’t worry. The meteor shower doesn’t have a noticeable peak like others. It “rambles” along steadily from the end of July into the beginning of August, when it joins up with the Perseids Meteor shower—but more on that next month.

The Delta Aquarids’ can reach a maximum rate 15 to 20 meteors per hour in a dark sky with no moon. Since August’s full moon arrives early, take advantage of the moonless nights towards the end of July. Skygazing for this meteor shower is a bit better in the Southern Hemisphere, but can still be quite visible in the southern United States. 

The same skygazing rules that apply to pretty much all space-watching activities are key this month: Go to a dark spot away from the lights of a city or town and let the eyes adjust to the darkness for about a half an hour. 

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Just in time for the light-filled days before the summer solstice in the Northern Hemisphere, the National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST) has released some stellar new images of the sun. Observations from the biggest and most powerful solar telescope on Earth show the movement of plasma in the solar atmosphere, intricate details of the sunspot regions, and the sun’s roiling convective cells. One of DKIST’s first-generation instruments, called the Visible-Broadband Imager, obtained these snaps of the sun that were released to the public on May 19.

The sunspots in the images are cool and dark regions on the sun’s “surface,” called the photosphere. Although sunspots are short-lived, strong magnetic fields persist here. The sunspots vary in size, but many are about the size of Earth, if not even bigger. Groups of sunspots can erupt in explosive events such as solar flares or coronal mass ejections (CME), which generate solar storms. Flares and CMEs influence the sun’s outermost atmospheric layer called the heliosphere, and these disturbances have a long reach, even messing with Earth’s infrastructure.

[Related: The sun’s chromosphere is shades of golden in these new images.]

Sunspot activity is also tied to cycles of about 11 years. During a cycle, sunspot and flare activity will rise to a peak solar maximum, when the sun’s poles switch places. Then the activity recedes, falling to almost zero at solar minimum. Our most recent solar cycle, Solar Cycle 25, began in 2019, and is on the upswing: The next solar maximum is expected to take place in 2025.

Astronomers and solar physicists don’t know what creates sunspots or drives these solar cycles, but understanding more can help Earth prepare for CMEs. These ejections can hurl giant clouds of charged particles that slam into our planet’s magnetic field, affecting satellites, radio communications, and even the power grid. 

Not all CMEs wreak havoc, though. Some cause the colorful aurora borealis (or northern lights) in the Northern Hemisphere and aurora australis in the Southern Hemisphere. In April, a CME generated a severe geomagnetic storm. While this geomagnetic storm was not disruptive, the northern lights it made were visible as far south as Arizona. 

[Related: How hundreds of college students are helping solve a centuries-old mystery about the sun.]

The images also show convection cells, which measure up to 994 miles across, in the sun’s quiet regions down to a resolution of about 12 miles. The convection cells give the protosphere, or the visible surface of the sun, a speckled popcorn-like texture, as piping hot plasma rises up from the cells’ center and then travels out to the edges before cooling and falling. 

In the layers of the solar atmosphere, the chromosphere sits above the photosphere. The chromosphere sometimes has dark hair-like threads of plasma called fibrils or spicules. They range from 125 to 280 miles in diameter and erupt up to the chromosphere from the photosphere and last only for a few minutes. 

We can expect to see more stunning images of the cells and other solar features in the coming years, as the solar telescope becomes fully operational. DKIST is named in honor of the late Hawaiian Senator Daniel K. Inouye, is the largest solar telescope in the world at 13 feet-wide. It rests on the peak of the mountain and volcano Haleakalā (or “House of the Sun”) on the island of Maui. It is currently in Operations Commissioning Phase, the observatory’s learning and transitioning period. Scientists will use the solar telescope’s unique ability to capture data in unprecedented detail to better understand the sun’s magnetic field and drivers behind solar storms.

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A team of more than 1,000 astronomers and college students just took a step closer to solving one of the long-lasting mysteries of astronomy: Why is the sun’s outer layer, known as the corona, so ridiculously hot? The solar surface is 10,000°F, but a thousand miles up, the sun’s corona flares hundreds of times hotter. It’s like walking across the room to escape an overzealous space heater, but you feel warmer far away from the source instead of cooler, totally contrary to expectations.

The research team used hundreds of observations of solar flares—huge ejections of hot plasma from our star’s surface—to determine what’s heating up the sun’s corona, in results published May 9 in The Astrophysical Journal. What’s really striking about this result, though, is how they did it: with the help of hundreds of undergrads taking physics classes at the University of Colorado, totaling a whopping 56,000 hours of work over multiple years.

Lead author James Paul Mason, research scientist and engineer at the Johns Hopkins Applied Physics Laboratory, calls this a “win-win-win scenario.” He adds, “We were able to harness a ton of brainpower and apply it to a real scientific challenge, the students got to learn firsthand what the scientific process looks like.”

[Related: Volunteer astronomers bring wonders of the universe into prisons]

The classroom project began in 2020, when University of Colorado physics professor Heather Lewandowski found herself teaching a class on experimental physics, which suddenly had to pivot online due to the COVID-19 pandemic—quite the challenge, especially for a hands-on science course. Luckily, Mason had an idea for a solar flare project that needed a lot of hands, and Lewandowski, who usually researches a totally different topic in quantum mechanics, saw that as an opportunity for her students. 

“The question of why the sun’s corona is so much hotter than the ‘surface’ of the sun is one of the main outstanding questions in solar physics,” says Lewandowski. There are two leading explanations for this dilemma, known as the coronal heating problem. One theory suggests that waves in the sun’s mega-sized magnetic field push heat into the corona. The other claims that small, unseen solar flares called nanoflares heat it up, like using a thousand matches instead of one big blow torch. 

Nanoflares are too small for our telescopes to spot, but by studying the sizes of other larger flares, scientists can estimate the prevalence of these little radiation bursts. And, although artificial intelligence is improving every day, automated programs can’t yet do the kind of analysis that Mason and Lewandowski needed. Groups of students in Lewandowski’s class each used data on a different solar flare, getting into nitty-gritty detail to measure how much energy each one dumped into the corona. Together, their results suggest nanoflares might not be powerful enough to heat up the corona to the wild temperatures we see.

[Related: Small ‘sparks’ on the sun could be key to forecasting dramatic solar weather]

The scientific result is only half of the news, though. Lewandowski and Mason pioneered a new way to bring real research into the classroom, giving students a way to not only learn about science, but do it themselves. This type of large-scale student research effort is more common in biology and chemistry, but was pretty much unheard of in physics—until now. “The students participated in all aspects of the research from literature review, meetings with the principal investigator, a proposal phase, data analysis, and peer review of their analysis,” says Lewandowski. The involvement of many students, and their work in groups, is also a reminder that “science is inherently a collaborative endeavor,” she adds.

“I hope that we inspire some professors out there to try this with their classes,” says Mason. “I’m excited to see what kinds of results they’re able to achieve.”

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On Wednesday and Thursday, a particularly strange “hybrid” eclipse is coming to Australia, Indonesia, and some other parts of Southeast Asia, but you don’t have to be there to watch. Don’t miss it—the next one won’t happen for nearly another decade.

How to see the April 20 solar eclipse in person

The exact time of the eclipse will vary depending on your location, so you’ll need to check when it will be visible for you. Timeanddate.com has a particularly handy tool for figuring this out. To use it, click Path Map at the top of the page and see if you’re going to be under any part of the eclipse’s path. If so, zoom in to pinpoint where you are and click on the map to bring up an information box that shows when the event will be visible in local time.

Even if you’re in the partial eclipse zone, it’s worth stepping outside to take a peek at this celestial happening. “We are going to get coffee and freak out about the sky. It’s going to be fun,” says University of Melbourne astronomer Benji Metha about his eclipse plans. The moon will cover only about 10 percent of the sun where he is in southeastern Australia.

[Related: April 2023 stargazing guide]

If you’re in the eclipse’s path, be sure to come prepared. Never look directly at the sun. Eclipse glasses are readily available online, but make sure the ones you’re buying aren’t fake. Too late to buy? You can make your own eclipse projector instead. Unlike almost every other astronomical event, solar eclipses happen in the daytime, so you won’t really be able to spot other stars or deep sky objects at the same time. The sun and moon will be the only ones on stage.

Timeanddate is also hosting an eclipse livestream in collaboration with Perth Observatory in western Australia, where roughly 70 percent of the sun will be covered. Like Exmouth, Perth is 12 hours ahead of New York City, so live video will start at 10 p.m. ET on April 19 and continue until the partial eclipse ends around 12:46 a.m. ET on April 20.

Tune in, and you’ll be joining solar scientists around the world who are particularly interested in this event and the data they can gather from it. “I look forward to this eclipse, because it is a long-anticipated party,” says Berkeley heliophysicist Jia Huang. “A hybrid eclipse is very rare.”

When is the next eclipse?

If you miss the show, there are sure to be some incredible photos posted from the event, and you will be able to watch recordings online afterward. But if you want to see an eclipse in person, a few are coming to the States soon enough.

First, an annular solar eclipse will travel from Oregon to Texas on October 14, 2023, followed several months later by the next North American total solar eclipse from Texas up through Maine on April 8, 2024.

What to know about the four types of solar eclipses

Solar eclipses happen whenever Earth’s moon gets between us and the sun, aligning to block out the sunlight and cause an eerie daytime darkness. Eclipses are predictable, thanks to centuries of observational astronomy across many cultures, and “we can now forecast these events with incredible accuracy,” Metha says. It’s a good thing we know when they’re coming so we’re not surprised. “Imagine how many car accidents a sudden solar eclipse would cause if people were not expecting it,” he adds.

These celestial events come in a few flavors: total, partial, annular, and hybrid. In a total eclipse, the moon fully blocks out the sun. For a partial eclipse, the sun and moon aren’t quite lined up, so only a chunk of the sun is covered. Similarly, for an annular eclipse, some of the sun remains exposed—but this type happens when the moon is at its farthest point from Earth and appears smaller, creating a ring of light when it lines up with the sun. Hybrid eclipses, like the one happening this week, shift between total and annular due to the curvature of Earth.

Solar eclipses trace paths along Earth’s surface, with a path of totality—where you can see a total eclipse—in the center, surrounded by various shades of partial eclipse. The upcoming April 20 eclipse path of totality clips the northwestern corner of Australia and passes through the islands of Timor, Indonesia, and Papua New Guinea. The entirety of Australia, the Philippines, Malaysia, and parts of other Southeast Asian countries will experience at least a partial eclipse.

[Related: How worried should we be about solar flares and space weather?]

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Few places in the solar system get hotter than the surface of the sun. But contrary to expectations, the tenuous tendrils of plasma in the outermost layer of its atmosphere—known as the corona—are way more searing than its surface.

“It is very confusing why the solar corona is farther away from the sun’s core, but is so much hotter,” says University of California, Berkeley space sciences researcher Jia Huang. 

The solar surface lingers around 10,000 degrees Fahrenheit, while the thin corona can get as hot as 2 million degrees. This conundrum is known as the coronal heating problem, and astronomers have been working on solving it since the mid-1800s.

“Simply speaking, solving this problem could help us understand our sun better,” says Huang. A better understanding of solar physics is also “crucial for predicting space weather to protect humans,” he adds. Plus, the sun is the only star we can send probes to—the others are simply too far away. “Thus, knowing our sun could help understand other stars in the universe.”

A brief history of the coronal heating problem

During the 1869 total solar eclipse—an alignment of the sun, moon, and Earth that blocks out the bulk of the sun’s light—scientists were able to observe the faint corona. Their observations revealed a feature in the corona that they took as evidence of presence of a new element: coronium. Improved theories of quantum mechanics over 60 years later revealed the “new element” to be plain old iron, but heated to a temperature that was higher than the sun’s surface.

[Related: We still don’t really know what’s inside the sun—but that could change very soon]

This new explanation for the puzzling 1869 measurement was the first evidence of the corona’s extreme temperature, and kicked off decades of study to understand just how the plasma got so hot. Another way of phrasing this question is, where is the energy in the corona coming from, and how is it getting there? 

“We know for sure that this problem hasn’t yet been resolved, though we have many theories, and the whole [astronomy] community is still enthusiastically working on it,” says Huang. There are currently two main hypotheses for how energy from the sun heats the corona: the motion of waves and an explosive phenomenon called nanoflares.

Theory 1: Alfvén waves

The surface of the sun roils and bubbles like a pot of boiling water. As the plasma convects—with hotter material rising and cooler material sinking down—it generates the sun’s immense magnetic field. This magnetic field can move and wiggle in a specific kind of wave, known as Alfvén waves, which then push around protons and electrons above the sun’s surface. Alfvén waves are a known phenomenon—plasma physicists have even seen them in experiments on Earth. Astronomers think the charged particles stirred up by the phenomenon might carry energy into the corona, heating it up to shocking temperatures.

Theory 2: Nanoflares

The other possible explanation is a bit more dramatic, and is kind of like the sun snapping a giant rubber-band. As the sun’s plasma tumbles and circulates in its upper layer, it twists the star’s magnetic field lines into knotted, messy shapes. Eventually, the lines can’t take that stress anymore; once they’ve been twisted too far, they snap in an explosive event called magnetic reconnection. This sends charged particles flying around and heats them up, a happening referred to as a nanoflare, carrying energy to the corona. Astronomers have observed a few examples of nanoflares with modern space telescopes and satellites.

The coronal heating mystery continues

As is usually the case with nature, it seems that the sun isn’t simply launching Alfvén waves or creating nanoflares—it’s more than likely doing both. Astronomers just don’t know how often either of these events happen.

[Related: Hold onto your satellites: The sun is about to get a lot stormier]

But they might get some straightforward answers soon. The Parker Solar Probe, launched in 2018, is on a mission to touch the sun, dipping closer to our star than ever before. It’s currently flying through some outer parts of the corona, providing the first up-close look at the movements of particles that may be responsible for the extreme temperatures. The mission has already passed through the solar atmosphere once, and will keep swinging around for a few more years—providing key information to help scientists settle the coronal heating problem once and for all.

“I would be very confident that we could make big progress in the upcoming decade,” says Huang.

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April is officially Global Astronomy Month, a month-long celebration of all things celestial by Astronomers Without Borders, a US-based club that connects global skywatchers. The event features a Global Star Party and Sun Day and online lessons to highlight the conjunction of art and astronomy. April also happens to be an exciting month for space happenings in general. If you happen to get any stellar sky photos, tag us and include #PopSkyGazers.

[Related: Your guide to the types of stars, from their dusty births to violent deaths.]

April 5 and 6 – Full Pink Moon

The first full moon of spring in the Northern Hemisphere will reach peak illumination at 12:37 AM EDT on April 6. First glimpses of the full Pink Moon will be on April 5, but because it reaches peak illumination so early in Eastern Time, Western time zones will see it peak on the night of April 5.

April’s full moon also goes by many names. The “pink” references early springtime blooms of the wildflower Phlox subulata found in eastern North America. This month’s moon is also the Paschal Full Moon, which determines when the Christian holiday Easter is celebrated. Easter is always celebrated on the first Sunday after the first full moon of spring, so this year Easter will be on Sunday, April 9.

Every year, the April full moon is also called the Frog Moon or Omakakiiwi-giizis in Anishinaabemowin/Ojibwe, the It’s Thundering Moon or Wasakayutese in Oneida, and the Planting Moon or Tahch’atapa in Tunica, the language of the Tunica-Biloxi Tribe of Louisiana.

April 7 – 34P/PANSTARRS comet at its closest point in flyby

The Jupiter-family comet 364P/PANSTARRS will pass within 11 million miles (0.12 AU) of the Earth in early April. The comet will be in the “foxy” constellation Vulpecula and is expected to have a high brightness magnitude of about 12.3. It will be visible in the Northern and Southern hemispheres, but those in Northern latitudes will be able to see it better. 

[Related: A total solar eclipse bathed Antarctica in darkness.]

April 20 – Total solar eclipse

Eclipses are always an exciting event, but this one comes with a twist. A total solar eclipse occurs during a rare cosmic alignment of the Earth, moon, and sun. The next solar eclipse will be the first of its kind since 2013 and the last until 2031.

On April 20, a new moon will eclipse the sun, but it will falter a bit. Since it is slightly too far away from the Earth in its elliptical orbit to fully cover all of the sun, the moon will actually fail to cause a total solar eclipse for a brief moment. A ring of fire will be visible for a few seconds over the Indian Ocean, but the moonshadow will completely cover the sun and cause a total solar eclipse by the time it reaches Western Australia. Eclipse chasers in the town of Exmouth and on ships in the Indian Ocean will likely experience about one minute of darkness during the day.

A long display of Baily’s beads around the New Moon and a view of the sun’s pink chromosphere could also appear around the moon during totality on eclipse day. While this eclipse won’t really be visible in the US, we’re only a few months away from the 2023 annular solar eclipse, which will reach totality in the western part of the country this October. 

April 21, 22, and 23 – Lyrid meteor shower

The Lyrids are predicted to start late in the evening of April 21 or April 22 and last until dawn on April 23. The predicted peak is 9:06 EDT on April 23. While the peak of the Lyrids is narrow, the new moon falls on April 19, so it will not interfere with skygazing. 

Ten to 15 meteors per hour can be seen in a dark sky with no moon. The Lyrids are even known for some rare surges in activity that can sometimes bring them up to 100 per hour. The meteor shower will be visible from both the Northern and Southern hemispheres, but is much more active in the north.

The same skygazing rules that apply to pretty much all space-watching activities are key this month: Go to a dark spot away from the lights of a city or town and let the eyes adjust to the darkness for about a half an hour. 

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On a clear, moonless night, you might be able to see thousands of stars sparkling like jewels above. But a keen eye will notice that they don’t all look alike. Some glow brighter than others, and some display warm red hues.

In the beginning…

All stars form from a cloud of dust and gas when turbulence pushes enough of that material together, pressed into one body by gravity. As that clump collapses in on itself, it starts to spin. The material in the middle heats up, forming a dense core known as a protostar. Gravity draws even more material toward the developing star as it spins, making it bigger and bigger. Some of that stuff may eventually form planets, asteroids, and comets in orbit around the new star.

The stellar body remains in the protostar phase as long as material still collapses inward and the object can grow. This process can take hundreds of thousands of years.

The amount of mass that is gathered during that stellar formation process determines the ultimate trajectory of the star’s life—and what types of stars it will become throughout its existence.

Protostars, baby stars—and failures

As a protostar amasses more and more gas and dust, its spinning core gets hotter and hotter. Once it accumulates enough mass and reaches millions of degrees, nuclear fusion begins in the core. A star is born.

For this to occur, a protostar has to accumulate more than 0.08 times the mass of our sun. Anything less and there won’t be enough gravitational pressure on the protostar to trigger nuclear fusion. 

Those failed stars are called brown dwarfs, and they remain in that state for their lifetime, progressively cooling down without nuclear fusion to help release new energy. Despite their name, brown dwarfs can be orange, red, or black due to their cool temperatures. They tend to be slightly larger than Jupiter, but are much more dense.

Protostars that do acquire enough mass to become a star sometimes go through an interim phase. During a roughly 10 million-year period, these young stars collapse under the pressure of gravity, which heats up their cores and sets off nuclear fusion. 

In this stage, a star can fall into two categories: If it has a mass two times that of our sun, it is considered a T Tauri star. If it has two to eight solar masses, it’s a Herbig Ae/Be star. The most massive stars skip this early stage, because they contract too quickly. 

Once a sufficiently massive star begins to undergo nuclear fusion, a balancing act begins. Gravity still exerts an inward force on the newborn star, but nuclear fusion releases outward energy. For as long as those forces balance each other out, the star exists in its main sequence stage. 

Fueling main sequence stars

Main sequence stars, which can last for millions to billions of years, are the vast majority of stars in the universe—and what we can see unaided on dark, clear nights. These stars burn hydrogen gas as fuel for nuclear fusion. Under the super-hot conditions in the core of a star, colliding hydrogen fuses, generating energy. This process produces the chemical ingredients for a reaction that makes helium. 

Mass dictates what type of star an object will be during the main sequence stage. The more mass a star has, the stronger the force of gravity pushing inward on the core and therefore the hotter the star gets. With more heat, there is faster fusion and that generates more outward pressure against the inward gravitational force. That makes the star appear brighter, bigger, hotter, and bluer.

[Related: The Milky Way’s oldest star is a white-hot pyre of dead planets]

Many main sequence stars are also often referred to as “dwarf” stars. They can range greatly in luminosity, color, and size, from a tenth to 200 times the sun’s mass. The biggest stars are blue stars, and they are particularly hot and bright. In the middle are yellow stars, which includes our sun. Somewhat smaller are orange stars, and the smallest, coolest stars are red stars. 

The hottest stars are O stars, with surface temperatures over 25,000 Kelvin. Then there are B stars (10,000 to 25,000K), A stars (7,500 to 10,000K), F stars (6,000 to 7,500K), G stars (5,000 to 6,000K—our sun, with a surface temperature around 5,800K is one of these), K stars (3,500 to 5,000K), and M stars (less than 3,500K). 

Upsetting the balance to grow a giant star

As a star runs out of fuel, its core contracts and heats up even more. This makes the remaining hydrogen fuse even faster: It produces extra energy, which radiates outward and pushes more forcefully against the inward force of gravity, causing the outer layers of the star to expand.

As those layers spread out, they cool down, and that makes the star appear redder. The result is either a red giant or a red supergiant, depending on if it’s a low mass star (less than 8 solar masses) or a high mass star (greater than 8 solar masses). This phase typically lasts up to around a billion years.

Appearing more orange than red, some red giants are visible to the naked eye, such as Gamma Crucis in the southern constellation Crux (aka the Southern Cross).

The death and afterlife of a low-mass star

Stars die in remarkably different ways, depending on their masses. For a low-mass star, once all the hydrogen is nearly gone, the core contracts even more, getting even hotter. It becomes so scorching that the star can even fuse helium—which, because it’s an element heavier than hydrogen, requires more heat and pressure for nuclear fusion. 

As a red giant burns through its helium, producing carbon and other elements, it becomes unstable and begins to pulsate. Its outer layers are ejected and blow away into the interstellar medium. Eventually, when all of these layers have been shed, all that remains is the small, hot, dense core. That bare remnant is called a white dwarf.

[Related: Wiggly space waves show neutron stars on the edge of becoming black holes]

About the size of Earth, though hundreds of thousands of times more massive, a white dwarf no longer produces new heat of its own. It gradually cools over billions of years, emitting light that appears anywhere from blue white to red. These dense stellar remnants are too dim to see with a naked eye, but some are visible with a telescope in the southern constellation Musca. Van Maanen’s star, in the northern constellation Pisces, is also a white dwarf. 

The explosive stellar death of a high-mass star

Stars with mass eight times that of our sun typically follow a similar pattern, at least in the beginning of this phase. As the star runs low on helium, it contracts and heats up, which allows it to convert the resulting carbon into oxygen. That process repeats itself with the oxygen, converting it to neon, then the neon into silicon, and finally into iron. When no fuel remains for this fusion sequence, and energy is no longer being released outward from those reactions, the inward force of gravity quickly wins. 

Within a second, the outer layers of the star collapse inward. The core collapses and then rebounds, sending a shock wave through the rest of the star: a supernova. 

Life after a supernova for a star takes one of two paths. If the star had between eight and 20 times the sun’s mass during its main sequence stage, it will leave behind a superdense core called a neutron star. Neutron stars are even smaller in diameter than white dwarfs, at about the size of New York City’s length, and contain more mass than our sun.

But for the most massive stars, that remnant core will continue collapsing under the pressure of its own gravity. The result is a black hole, which can be as small as an atom but contain the mass of a supermassive star.

One such example is a star in a binary or multi-star system that accretes mass from a companion. With all that extra mass to burn, it can seem younger than its true age, appearing bluer and brighter. That, Gosnell says, is called a blue straggler star, because it seems to be “straggling behind its expected evolution.” 

Another odd type of star is sub-subgiant, Gosnell says. These stars also are found in binary systems, and are transitioning from the main sequence to the red giant branch, though they stay dimmer. This kind of subgiant star has “really active magnetic fields with lots of star spots on the surface,” she says. “And so you have these really magnetically active, visually dynamic stars as the star spots rotate in and out of view.” 

The ongoing ESA mission, she adds, is reviewing stars with a “much finer-toothed comb”—which may reveal the true variety and complexity of stars that have existed all along. As such missions “peel back the layers,” Gosnell says, “We start to see really interesting stories come out that challenge the edges of these categories.”

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Water is an essential ingredient for life as we know it, but its origins on Earth, or any other planet, have been a long-standing puzzle. Was most of our planet’s water incorporated in the early Earth as it coalesced out of the material orbiting the young sun? Or was water brought to the surface only later by comet and asteroid bombardments? And where did that water come from originally? 

A study published on March 7 in the journal Nature provides new evidence to bolster a theory about the ultimate origins of water—namely, that it predates the sun and solar system, forming slowly over time in vast clouds of gas and dust between stars.

”We now have a clear link in the evolution of water. It actually seems to be directly inherited, all the way back from the cold interstellar medium before a star ever formed,” says John Tobin, an astronomer studying star formation at the National Radio Astronomy Observatory and lead author of the paper. The water, unchanged, was incorporated from the protoplanetary disk, a dense, round layer of dust and gas that forms in orbit around newborn stars and from which planets and small space bodies like comets emerge. Tobin says the water gets drawn into comets “relatively unchanged as well.”

Astronomers have proposed different origins story for water in solar systems. In the hot nebular theory, Tobin says, the heat in a protoplanetary disk around a natal star will break down water and other molecules, which form afresh as things start to cool.  

The problem with that theory, according to Tobin, is that when water emerges at relatively warm temperatures in a protoplanetary disk, it won’t look like the water found on comets and asteroids. We know what those molecules look like: Space rocks, such as asteroids and comets act as time capsules, preserving the state of matter in the early solar system. Specifically, water made in the disk wouldn’t have enough deuterium—the hydrogen isotope that contains one neutron and one proton in its nucleus, rather than a single proton as in typical hydrogen. 

[Related: Meteorites older than the solar system contain key ingredients for life]

An alternative to the hot nebular theory is that water forms at cold temperatures on the surface of dust grains in vast clouds in the interstellar medium. This deep chill changes the dynamics of water formation, so that more deuterium is incorporated in place of typical hydrogen atoms in H₂O molecules, more closely resembling the hydrogen-to-deuterium ratio seen in asteroids and comets.  

“The surface of dust grains is the only place where you can efficiently form large amounts of water with deuterium in it,” Tobin says. “The other routes of forming water with deuterium and gas just don’t work.” 

While this explanation worked in theory, the new paper is the first time scientists have found evidence that water from the interstellar medium can survive the intense heat during the formation of a protoplanetary disk. 

The researchers used the European Southern Observatory’s Atacama Large Millimeter/submillimeter Array, a radio telescope in Chile, to observe the protoplanetary disk around the young star V883 Orionis, about 1,300 light-years away from Earth in the constellation Orion. 

Radio telescopes such as this one can detect the signal of water molecules in the gas phase. But dense dust found in  protoplanetary disks very close to young stars often turns water into ice, which sticks to grains in ways telescopes cannot observe. 

But V883 Orionis is not a typical young star—it’s been shining brighter than normal due to material from the protoplanetary disk falling onto the star. This increased intensity warmed ice on dust grains farther out than usual, allowing Tobin and his colleagues to detect the signal of deuterium-enriched water in the disk. 

“That’s why it was unique to be able to observe this particular system, and get a direct confirmation of the water composition,” Tobin explains. ”That signature of that level of deuterium gives you your smoking gun.” This suggests Earth’s oceans and rivers are, at a molecular level, older than the sun itself. 

[Related: Here’s how life on Earth might have formed out of thin air and water]

“We obviously will want to do this for more systems to make sure this wasn’t just that wasn’t just a fluke,” Tobin adds. It’s possible, for instance, that water chemistry is somehow altered later in the development of planets, comets, and asteroids, as they smash together in a protoplanetary disk. 

But as an astronomer studying star formation, Tobin already has some follow up candidates in mind. “There are several other good candidates that are in the Orion star-forming region,” he says. “You just need to find something that has a disk around it.”

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On Friday, February 17, a part of the sun erupted. A piercingly bright flash of light—a solar flare—shone briefly from the left limb of our star, where it was captured in an ultraviolet image by NASA’s Solar Dynamics Observatory spacecraft.

“It wasn’t the largest in history by any means, but it was a significant X flare,” Thomas Berger, a solar physicist and director of the Space Weather Technology, Research, and Education Center at the University of Colorado Boulder. (The “X” refers to the letter grading system of solar flare intensity, which ranges from minor A-class to severe X-class flares. “Solar flares of that magnitude will generally cause some radio-interference on the sunlit side of the Earth for an hour or two,” he says. Ultimately, this one was fairly mild—the most powerful solar flare ever recorded, in 2003, was more than 100 times more powerful by comparison—and did not cause any major problems. 

That said, we’re about to enter a more volatile chapter in the sun’s 11-year cycle of magnetic activity. Solar flares are one of three major forms of solar-eruption activity, along with coronal mass ejections and radiation storms, which are likely to increase in frequency over the next few years, according to Berger.

”We are in the rising phase of Solar Cycle 25, and it is expected that activity is going to increase,” he says. (It’s known as Solar Cycle 25 because scientists first began keeping detailed records of sunspots in 1755, and there have been 25 cycles since that time.) The peak of this period, known as the solar maximum, should occur around 2025. The last solar maximum was in 2014.

[Related: How worried should we be about solar flares and space weather?]

That rise in activity that could majorly impact planned space activities, such as the rapidly growing constellations of low-Earth orbit satellites. And a 2025 solar maximum would coincide with NASA’s Artemis III, which aims to return humans to the surface of the moon—not the safest place to be during a solar radiation storm.

 “It’s going to be a really interesting time if we get an extreme storm in this solar cycle,” Berger says.

What is the solar magnetic cycle?

The sun is a giant sphere of roiling, superheated plasma that is essentially electrically charged gas with monstrously powerful magnetic fields.

For reasons astronomers don’t yet understand, the activity of these magnetic fields increases and decreases over an 11-year cycle. The cycle also includes changes in the dark areas on the star’s surface, otherwise known as sunspots, with more spots appearing as the sun moves toward solar maximum.

“Sunspots are the source of solar magnetic eruptions,” Berger says. “The bigger the sunspot, the bigger the explosion. The more active the sun, the more sunspots, and the bigger the sunspots get.”

The current solar cycle stands out so far in a big way: So far, it’s more active than forecast by groups like the the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, with more sunspots showing up on the sun that predicted.    

“We don’t know if it will continue to be more active than the forecast,” Berger says. “It’s fairly early on in the game here and could regress back to that weak forecast any month.”

Will solar eruptions disrupt Earth in 2025?

Solar eruptions occur when the magnetic field lines in a sunspot get twisted and snap, Berger says, causing an explosion with three possible outcomes.

The first is a solar flare, like that seen on February 17, which is primarily a release of photons. The second is a coronal mass ejection, or a large release of plasma into interplanetary space. And the third is a radiation storm fueled by accelerating energy particles like protons, elections, and ions. Coronal mass ejections can also sometimes generate a radiation storm by pushing charged particles in front of them as they speed through space.

Solar flares, if intense enough, can cause radio interference on the sunlit side of the Earth. Coronal mass ejections are the outbursts that really cause issues. The charged plasma can generate a geomagnetic storm when it hits our planet’s magnetosphere, resulting in awe-inspiring auroras at the poles, while also wreaking havoc on both power grid technology and satellite technology, Berger says. A big geomagnetic storm can heat the atmosphere so that it swells, dragging on low-flying satellites and even pulling some from orbit, as was the doomed case of 40 newly launched Starlink satellites on February 4, 2022.

Not every coronal mass ejection will reach Earth, however. Many, like the ejection associated with the February 17 eruption, fly off into space away from our planet. The question is whether any more will be aimed our way as we hurtle toward the solar maximum.

“Recent research is really beginning to confirm that almost every solar cycle has a really, really big eruption,” Berger says, “So it’s really just a matter of what direction in space it’s going.”

How do we plan for the sun’s unruly future?

Really  powerful solar eruptions can lead to geomagnetic storms that damage electronics on the ground, such as the the storm in 1989 that knocked out some power grids. But the risks are higher today than in 1989, if just because there’s a lot more technology, and people, in space on a regular basis. For instance, there were more than 5,700 satellites in orbit at the end of 2022, while there were less than 500 satellites in 1989.

“If we do get an extreme geomagnetic storm now, there’s so much stuff up there that’s going to be moving all over the place,” Berger says. “We are concerned with an elevated risk of collision from the next one.”

[Related: What happens when the sun burns out?]

With NASA planning on heading back to the moon and eventually to Mars, scientists will need to get a lot better at forecasting solar eruptions. Physicists like Berger and researchers at the Space Weather Prediction Center can currently predict solar eruptions, but with what meteorologists would consider fairly lousy accuracy and detail compared to 10-day forecast of sunshine and rain.

“We can tell you when the coronal mass ejection will hit, roughly, plus or minus 10 hours,” Berger explains, “But we don’t have a good way to forecast what is going to happen in the low-Earth orbit environment.” In other words, it’s tough to say how much a geomagnetic storm will affect the operation and trajectory of satellites and regular electrical operations on the ground.

The sticking point for better forecasts is that while NOAA runs an ongoing simulation of the Earth’s upper atmosphere, that model isn’t yet able to assimilate real-time data the way terrestrial weather forecast models can. “That is a research program that will take several years to come to fruition,” Berger says.

In the meantime, the sun will keep climbing toward solar maximum in 2025. But even after that peak, it doesn’t mean satellites and astronauts are out of the woods as far as solar storms are concerned. “Really any time between now and 2028 or 2029, we could potentially get a large eruption beginning to hit the Earth,” Berger says. That probably won’t affect daily life, but NASA and satellite operators will need to keep an eye toward the sun.      

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Well, there’s a reasonable explanation. Heat travels through the cosmos as radiation, an infrared wave of energy that migrates from hotter objects to cooler ones. The radiation waves excite molecules they come in contact with, causing them to heat up. This is how heat travels from the sun to Earth, but the catch is that radiation only heats molecules and matter that are directly in its path. Everything else stays chilly. Take Mercury: the nighttime temperature of the planet can be 1,000 degrees Fahrenheit lower than the radiation-exposed day-side, according to NASA.

Compare that to Earth, where the air around you stays warm even if you’re in the shade—and even, in some seasons, in the dark of night. That’s because heat travels throughout our beautiful blue planet by three methods instead of just one: conduction, convection, and radiation. When the sun’s radiation hits and warms up molecules in our atmosphere, they pass that extra energy to the molecules around them. Those molecules then bump into and heat up their own neighbors. This heat transfer from molecule to molecule is called conduction, and it’s a chain reaction that warms areas outside of the sun’s path.

[Related: What happens to your body when you die in space?]

Space, however, is a vacuum—meaning it’s basically empty. Gas molecules in space are too few and far apart to regularly collide with one another. So even when the sun heats them with infrared waves, transferring that heat via conduction isn’t possible. Similarly, convection—a form of heat transfer that happens in the presence of gravity—is important in dispersing warmth across the Earth, but doesn’t happen in zero-g space.

These are things Elisabeth Abel, a thermal engineer on NASA’s DART project, thinks about as she prepares vehicles and devices for long-term voyages through space. This is especially true when she was working on the Parker Solar Probe, she says.

“The job of that heat shield,” Abel says, is to make sure “none of the solar radiation [will] touch anything on the spacecraft.” So, while the heat shield is experiencing the extreme heat (around 250 degrees F) of our host star, the spacecraft itself is much colder—around -238 degrees F, she says.

[Related: How worried should we be about solar flares and space weather?]

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Space weather can be wild. Coronal mass ejections (CMEs), which can produce solar flares, are especially blustery, and can cause everything from beautiful auroras that dance across the night sky or power outages and other technological interference. They can even endanger astronauts by throwing radiation their way.

But like with weather on Earth, can we improve predicting when bursts of electromagnetic energy like solar flares are coming?

[Related: How worried should we be about solar flares and space weather?]

A team of scientists from NorthWest Research Associates (NWRA) investigated data from NASA’s Solar Dynamics Observatory (SDO) and found some new clues for weather prediction in the sun’s upper atmosphere. The identified small signals in the sun’s corona that can help pinpoint when regions in the sun are more likely to produce the bursts of light and particles released from the sun during a solar flare.

They detail the findings in a study published January 16 in The Astrophysical Journal. Most importantly, they discovered that in the regions about to flare, the corona produces flashes “like small sparklers before the big fireworks.”

Previously, scientists have studied activity in the lower layers of the sun’s atmosphere (specifically the protosphere and chromosphere) and how it can signal impending flare activity in active regions. This warning is typically marked by groups of strong magnetic regions of the sun that appear darker and cooler than the surrounding area called sunspots.

“We can get some very different information in the corona than we get from the photosphere, or ‘surface’ of the sun,” said KD Leka, lead author on the new study from Nagoya University in Japan, in a statement. “Our results may give us a new marker to distinguish which active regions are likely to flare soon and which will stay quiet over an upcoming period of time.”

[Related: World’s largest telescope array is almost ready to stare straight into the sun.]

The team used a new publicly available image database of the active regions on the sun captured by the SDO. It combines more than eight years of images of images taken using ultraviolet and extreme-ultraviolet light. The images and a newly developed statistical method created by co-author Graham Barnes will help scientists better understand the physics happening in the sun’s magnetically active regions.

“It’s the first time a database like this is readily available for the scientific community, and it will be very useful for studying many topics, not just flare-ready active regions,” said Karin Dissauer, a co-author and NWRA research scientist who led the database project along with engineer and co-author Eric L. Wagner, in a statement. “With this research, we are really starting to dig deeper. Down the road, combining all this information from the surface up through the corona should allow forecasters to make better predictions about when and where solar flares will happen.”

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Following over a decade of research, including two years of testing origami-inspired components, a small prototype satellite designed to harvest solar energy launched yesterday morning aboard SpaceX’s most recent Falcon 9 rocket launch in Cape Canaveral, Florida. If its initial experiments are successful, arrays similar to Caltech’s Space Solar Power Demonstrator (SSPD) could one day beam essentially endless renewable energy back to Earth via microwave transmitters.

After reading a Popular Science article on the concept in 2011, Caltech Board of Trustees lifetime member Donald Bren approached the school in hopes of making the science fiction idea a reality. The resultant Space Solar Power Project, co-funded by defense manufacturer Northrop Grumman alongside the Bren family’s $100 million endowment, saw its first major milestone completion yesterday via the SSPD arrival above Earth.

[Related: This space-adapted solar panel can fold like origami.]

Over the next few weeks and months, the roughly 110-pound prototype will send back data on three main projects. The Deployable on-Orbit ultraLight Composite Experiment (DOLCE) will test lightweight, foldable structures that can unfurl to collect sunlight. Meanwhile, ALBA (Italian for “dawn”), a collection of 32 different varieties of photovoltaic cells, will determine which could work best in the space’s extremely harsh environment. Finally, the Microwave Array for Power-transfer Low-orbit Experiment (MAPLE) will test microwave transmitters that may one day transmit the collected solar power via wireless electricity.

Speaking yesterday with The Los Angeles Times, Caltech senior researcher Michael Kelzenberg explained that the SSPD’s first tests are not meant to supply Earth with solar space energy just yet. Instead, the team hopes to begin determining which materials, designs, and methods could result in the most efficient and affordable solutions in the future.

[Related: Solar energy company wants to bolt panels directly into the ground.]

It’s hard to overstate just how revolutionary the prospect of space solar energy farming could be for humanity’s power needs. In 2007, a study from the National Space Society estimated that a single, half-mile wide band of photovoltaics orbiting above Earth could hypothetically generate the same amount of energy as the entire planet’s remaining oil supplies over the course of just one year. To do this, Popular Science explained in 2011 that high energy lasers could transmit the solar supply back to Earth at roughly 80 percent efficiency to a global network of receivers, thus providing clean power across the world, even to places with previously unreliable electricity grids.

A multitude of hurdles remain, most notably the vast costs attached to any space engineering project. Still, as Ali Hajimiri, Caltech’s Bren Professor of Electrical Engineering and Medical Engineering and co-director of SSPP, explained in a statement, “no matter what happens, this prototype is a major step forward.” 

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The sun roils with heat as thermonuclear reactions in its center produce high amounts of energy. Day to day, that energy is responsible for making Earth livable. But sometimes, solar flares can burst forth, sending highly energetic particles hurtling at top speeds into space. If our planet is in the radiation’s path, it can wreak havoc on our lives. 

[Related: What happens when the sun burns out?]

Although such consequences are rare, satellites and technology that relies on electricity and wireless networks are particularly vulnerable. In 1989, a geomagnetic storm set off by a powerful solar flare triggered a major blackout across Canada that left six million people without electricity for nine hours. In 2000, a solar eruption caused some satellites to short-circuit and led to radio blackout. In 2003, a series of solar eruptions caused power outages and disrupted air travel and satellite systems. And in February 2022, a geomagnetic storm destroyed at least 40 Starlink satellites just as they were being deployed, costing SpaceX more than $50 million.

What exactly are solar flares and solar storms?

Generally speaking, the term “solar storm” describes when an intense eruption of energy from the sun shoots into space and interacts with Earth. Charged particles constantly flow away from the sun into space in what is called the solar wind. But more significant eruptions can originate as solar flares, often from temporarily dark patches called sunspots, and intense explosions called coronal mass ejections. Any kind of variation in this activity can cause auroras. 

Solar flares are essentially flashes of light. They happen when strong solar magnetic fields protruding from the surface of the sun snap, releasing immense amounts of electromagnetic radiation at extremely high speeds. When that radiation slams into Earth, it injects energy into our planet’s ionosphere, the uppermost reaches of our atmosphere, explains Guhathakurta. The extreme ultraviolet radiation from the sun can polarize the particles in Earth’s ionosphere, she says, which can have cascading effects on any other charged particles in the vicinity—meaning anything that uses electricity is at risk.

And solar flares travel at the speed of light, says Jesse Woodroffe, who leads the space weather research program in NASA’s Heliophysics Division. That makes them difficult to anticipate and prepare for. “There is no way to get a signal to Earth faster than the solar flares, which are already traveling at the speed of light,” he notes. “So you have to predict the flare itself is going to happen. And that is a challenging science problem that we have not yet cracked.”

While solar flares are intense bursts of radiation, coronal mass ejections are explosions of energy particles. As such, they travel a bit slower. They occur when large portions of the outer atmosphere of the sun (the corona) explodes, sending superheated gas out into space. These “big blobs of solar material are ejected out at a very high speed, hundreds and hundreds of kilometers per second, but it is much slower than the speed of light,” Woodroffe adds. Those can take anywhere from half a day to three days to reach Earth, he says.

How to forecast space weather

Forecasting space weather isn’t quite like terrestrial weather forecasts. The big difference: On Earth, meteorologists have millions of measurements they can make and integrate into their predictive models. In space, Woodroffe says, there are just a few places scientists can put instruments to observe solar activity.

NASA shares the data from its solar observatories with the National Oceanic at Atmospheric Administration, which provides a probabilistic forecast of geomagnetic storm warnings and watches based on likelihood and geomagnetic intensity. Depending on how fast a solar storm is moving, they can send out warnings a few days before that space weather touches Earth, or just a couple of hours.

The ultimate goal, Woodroffe says, is to improve space weather forecasting to be on par with hurricane forecasting. His Earth-focused colleagues can predict where a hurricane might go by running different models, producing a range of outcomes within a high range of confidence, he says. “We are developing those sorts of capabilities for space weather.”

Are we seeing more solar flares?

So, back to those apocalyptic solar flare headlines. Is the sun really getting feistier and threatening the collapse of modern society each week? 

Space weather activity hasn’t changed recently, says Guhathakurta—but humanity has. In the past century, people have become increasingly reliant on electronics, and anything with an “on and off switch is vulnerable to solar storms,” she says. 

[Related: Make your own weather station with recycled materials]

When those energy particles come surging from the sun to Earth, the disturbance they cause in our planet’s magnetic field “creates electromagnetic fluctuation and voltage fluctuation, which can penetrate beneath the ground and create fluctuations on our electric power grid,” Guhathakurta says. And with growing dependence on devices that rely on orbiting satellite systems like GPS, our electronics are even more exposed to bursts of solar radiation.

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China just completed construction on what is now the world’s largest telescope array at the edge of the Tibetan Plateau. The country plans to aim it at our sun as part of what one expert is calling “the golden age of solar astronomy.” As reported in Nature earlier today, the Daocheng Solar Radio Telescope (DSRT) cost 100 million yuan ($14 million USD), and is comprised of over 300 antenna dishes situated in a 3 kilometer (1.87 miles) circumference formation. Initial testing will begin in June 2024, and will focus on an upcoming increase in solar activity over the next few years, particularly on how solar eruptions affect Earth.

[Related: What happens when the sun burns out?]

The terrestrially situated DSRT joins NASA’s Parker Solar Probe and the European Space Agency’s Solar Orbiter, launched in 2018 and 2020 respectively, in ongoing efforts to study the sun’s complexities. Radio telescopes such as the DSRT are especially helpful when studying activity in the sun’s upper atmosphere, or corona, such as solar flares. Another solar weather event, a coronal mass ejection (CME), involves hot plasma eruptions that release high-energy particles which then can travel to Earth. This radiation often damages power grids and satellites—such as what happened in February 2022 when a solar storm blasted 40 Starlink satellites out of orbit.

“China now has instruments that can observe all levels of the sun, from its surface to the outermost atmosphere,” Hui Tian, a solar physicist at Beijing’s Peking University, told Nature.

[Related: How worried should we be about solar flares and space weather?]

Compared to similar telescopic arrays, the DSRT will be more finely tuned, and thus potentially capture weaker signals from high-energy particles emitted during CME events. As the sky above us becomes increasingly—and sometimes problematically—crowded by satellites, developing more reliable, accurate, and detailed analysis of solar activity will be critical to further expansion.

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It looks like many things to many people. The Stay Puft Marshmallow Man from the classic 80s movie “Ghostbusters.” A ScrubDaddy sponge. An emoji. And a jack-o’-lantern, just in time for Halloween. Last week, NASA’s Solar Dynamics Observatory captured an image of the sun’s surface in an apparent smile. “Today, NASA’s Solar Dynamics Observatory caught the sun ‘smiling.’ Seen in ultraviolet light, these dark patches on the sun are known as coronal holes and are regions where fast solar wind gushes out into space,” NASA wrote in a tweet.

The patches making up the face in the image are coronal holes—cooler sections of the sun’s outer layer. This layer is usually around 10,000 degrees Fahrenheit. The coronal holes show areas of high magnetic-field activity that steadily release solar wind. These cosmic gusts are a flow of protons, electrons, and other particles that travel through space.

[Related: Scientists just spotted a massive storm from a sun-like star.]

While this image is a visual treat, the activity behind it might prove to be more of a trick back here on Earth. The holes might be a solar storm that could generate a beautiful aurora borealis in Earth’s more northern latitudes or wreak havoc on the planet’s telecommunication systems. Solar storms like these can become troublesome when the particles make it to Earth’s atmosphere, where television and radio antennae can pick up their signals. A big enough solar storm can cause power outages and damage electrical grids. The Carrington Event in 1859 was one of the most significant solar storms in recorded history and caused fires at telegraph stations and even auroras in tropical regions. With significantly more telecommunications in the 21st Century, a similar event could cause severe problems to the technology we rely on daily.

One more recent spooky solar storm was the appropriately named Halloween Storms of 2003. With minimal warning, three giant sunspot groups formed on the sun’s surface by October 26, 2003. The largest of these spots was 13 times bigger than Earth’s, and 17 major solar flares erupted from the sun. “The storms affected over half of the Earth-orbiting spacecraft, intermittently disrupting satellite TV and radio services and damaging a Japanese scientific satellite beyond repair,” according to a National Oceanic Atmospheric Administration post. “The solar activity also sent several deep-space missions into safe mode or complete shutdown and destroyed the Martian Radiation Environment Experiment aboard NASA’s Mars Odyssey mission. At the height of the storms, astronauts aboard the International Space Station had to take cover from the high radiation levels, which had only happened twice before in the mission’s history.”

[Related: Violent space weather could limit life on nearby exoplanets.]

According to some researchers, the planet is also long overdue for a massive solar event. “Scientists expect that to happen on average, with a couple percent probability, every year, and we’ve just dodged all these magnetic bullets for so long,” University of California at San Diego physics professor Brian Keating told The Washington Post. “So it could be really scary, and the consequences could be much more dramatic, especially in our technology-dependent current society. There could be something on our way for Halloween night after all. Pretty spooky, but hopefully not too spooky.”

The Solar Dynamics Observatory was first launched in 2010 with a mission to investigate how solar activity is created and drives space weather. The spacecraft measures the sun’s atmosphere, magnetic field, energy output, and the sun’s steamy interior. But the Solar Dynamics Observatory is hardly the only NASA entity working hard to bring spooky images back to Earth this Halloween—the Hubble Telescope also captured a spooky “cosmic keyhole” that looks a bit like a portal into another dimension on October 28.

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The autumnal equinox is upon us, and vibrant falling leaves aren’t the only things returning to our skies. The aurora borealis, a.k.a. the northern lights, will begin to dazzle in high-latitude skies far more often. But why? Popular Science and UCLA space science professor Robert McPherron answer your questions.

What is the autumnal equinox?

For residents of the Northern Hemisphere, the autumnal equinox marks the beginning of fall. On the equinox, day and night are approximately the same length—the name “equinox” comes from Latin words meaning “equal” and “night.” The 2022 autumnal equinox for the Northern Hemisphere is on September 22 at 9:04 pm EDT. At this time, unlike during the solstices, Earth is tilted neither toward nor away from the sun. When the sun shines on the equator, it results in equal light for the Northern and Southern Hemispheres. 

What is an aurora? How does it happen?

While auroras light up the night sky with their brilliant greens and pinks, much more is happening behind the scenes. The aurora borealis and aurora australis, around the north and south poles, respectively, are caused by the sun’s continuous solar wind and solar storms, specifically coronal mass ejections, which are huge bursts of plasma. Through these ejections and via this wind, the sun sprays electrons into Earth’s magnetic field. There, these charged particles combine with the field and shoot into Earth’s atmosphere, following the path of the magnetic field towards the poles. As these particles collide with molecules in the atmosphere, they produce light. 

[Related: We finally know what sparks the Northern Lights]

McPherron likens the process to switching off old television sets: “When you turn them on, if you had good hearing, you’d hear a very high pitched whine indicative of a very high frequency” caused by a beam of electrons. “And if you turned it off, you’d see a spot right in the center of the screen.” That glowing spot on the fluorescent screen results when a beam of electrons hits it from the inside. “And that’s exactly what the aurora is,” he says. “It is electrons coming down along a magnetic field line, and the screen is the atmosphere.”

Where do the colors come from?

As the electrons enter Earth’s atmosphere, they excite gases, namely oxygen and nitrogen. The oxygen and nitrogen molecules, flush with energy beyond their normal state, emit photons as they go back to their baseline levels, resulting in light. Oxygen emits green and red light, while nitrogen emits blue.

Why is auroral activity high around the equinox?

This answer is more complicated but involves two effects: the equinoctial effect and the Russel-McPherron effect–recognize the name? The first arises from Earth’s poles meeting the solar winds at a right angle, while in the latter, the solar winds are antiparallel to Earth’s magnetic field. Together, these two effects explain an increase in autumn auroral activity and make the weeks around the equinoxes the prime times to view auroras.

[Related: Meet STEVE, and 7 other mysterious glowing things you’ll find in the night sky]

In other words, the tilt of Earth’s axes enhances “the strength of the solar wind magnetic field” that’s interacting with our planet, McPherron says.

How can I see an aurora?

First, you’ll likely need to travel north. Unless you’re in Flin Flon, Manitoba, Canada, in which case, according to McPherron, stay exactly where you are—that’s a prime spot to catch the northern lights. The best place to view an aurora is in the auroral zone, which is centered around 67º north of the equator, but the aurora borealis has been reported as far south as Hawaii during a time of significant solar flares in the 1800s. 

In the US, the best states to view the northern lights include Alaska, Maine, and Minnesota, among others. Although solar activity that causes auroras occurs all day, the best way to see auroras with the naked eye is at night, McPherron says. Activity is most frequent around 11 p.m., but auroras can occur from dusk to dawn, he adds. 

But no matter what, if you see an aurora, you are in for a treat. Watch for the sky to begin to brighten, ramping up over 15 to 20 minutes. “And then you’ll just see a burst poleward in all of this fantastic activity,” McPherron says.

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It’s certainly been an exciting few months for telescopes. The National Science Foundation (NSF) has just released stellar new images of the sun’s face, courtesy of the Daniel K. Inouye Solar Telescope (DKIST) in Hawaii. The images show the chromosphere, the middle layer of the sun’s atmosphere, which can reach over 13,000 degrees Farenheit. The pictures vaguely resemble the bright yellow flowers in Vincent van Gogh’s painting, “Sunflowers.”

Hairs of fiery plasma flow into the corona, the suns outermost atmospheric level, from a pattern of pores. The sun’s chromosphere sits below the corona, which is usually invisible and historically has only been seen during a total solar eclipse. But new technology like this telescope has changed that.

The blistering blobs are called granules and are about 994 miles wide. Each of these portraits shows an area about 51,260 miles wide, only a small percentage of the sun’s total diameter.

[Related: NASA’s solar probe reveals stunning results after swooping in close to the sun.]

The images were taken on June 3 and released to the public this week. Named for the late Hawaiian Senator Daniel K. Inouye, the DKIST is currently the largest solar telescope in the world. The 13 feet-wide telescope rests on the peak of the mountain and volcano Haleakalā (or “House of the Sun”) on the island of Maui. It’s focused on understanding the explosive behavior of the sun and observing its magnetic fields. It will also help scientists predict and prepare for solar storms called coronal mass ejections (CME). CME bursts send hot plasma from the sun’s corona to Earth and interfere with electricity and internet connections. It is part of the NSF’s National Solar Observatory.

“With the world’s largest solar telescope now in science operations, we are grateful for all who make this remarkable facility possible,” said Matt Mountain, AURA President, in a press release. “In particular we thank the people of Hawai‘i for the privilege of operating from this remarkable site, to the National Science Foundation and the US Congress for their consistent support, and to our Inouye Solar Telescope Team, many of whom have tirelessly devoted over a decade to this transformational project. A new era of Solar Physics is beginning!”

[Related: What happens when the sun burns out?]

This telescope is not free from controversy since its location is in a sacred spot of Native Hawaiians. Mountain tops likes this one are regarded as wao akua, (realm of the gods), places where both deities and demigods existed on Earth. They are still sacred places of reverence, where many Native Hawaiians visit to honor ancestors and practice other spiritual traditions.

In a 2017 interview with Science, Kaleikoa Kaeo, a Hawaiian-language educator at the University of Hawaii Maui College in Kahului and a leader in opposition to the telescope said, “As a people, we don’t have control of some of our most sacred spaces. They say it’s Hawaiian culture versus science. I say, ‘No, it’s Hawaiian culture versus white supremacy.'”

Following protests in 2015 and 2017, the telescope’s officials began to meet with working groups of Native Hawaiians, who have since gained more authority over the site. The peak also remains open to native Hawaiians and a sun-centered middle-school curricula that highlights Hawaii’s long history of studying astronomy has been developed.

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When you see a distant star in the night sky, it might twinkle and look like it has five points. This is largely a trick of the eye. Zoomed in, most stars are just round balls of gasses and dust. As they age, heat up, consume other matter, and sometimes explode, they take on more abstract and asymmetrical shapes—unlike the pentagrams you scribble on your notebook.

Now let’s zoom out again, way beyond Earth’s field of view. The imprints of individual stars form clusters—more complex than the constellations you know—which mold the immense systems underpinning the universe. These formations are so vast, it’s hard to even guess where their contours might fall.

That’s why astronomers need Gaia. The space observatory, which consists of two spinning telescopes and three “motion detectors,” is mapping out stars and other celestial bodies across the Milky Way. Since it launched in 2013, Gaia has pinpointed 1.8 billion objects, like a “stellar stream” that’s about a billion years old. The mission produced a near-complete 3D rendering of the home galaxy back in 2018, and continues to churn out data for researchers to tinker with. 

[Related: Astronomers just mapped the ‘bubble’ that envelops our planet]

In its latest haul of knowledge, Gaia shares a more intimate profile of the stars it’s documented. On June 13, the European Space Agency (ESA) posted fresh findings from the project, including a trove of light spectroscopy images and records of tsunami-sized tremors across the Milky Way. 

“The catalog includes new information including chemical compositions, stellar temperatures, colors, masses, ages, and the speed at which stars move towards or away from us (radial velocity),” the ESA wrote on its website. “Much of this information was revealed by the newly released spectroscopy data.”

Beyond surveying hundreds of thousands binary systems, asteroids, quasars, and macromolecules, the space observatory also detected oscillating motions emanating from stellar surfaces. Astronomers call these “starquakes.”

“Previously, Gaia already found radial oscillations that cause stars to swell and shrink periodically, while keeping their spherical shape. But Gaia has now also spotted other vibrations that … change the global shape of a star and are therefore harder to detect,” the ESA explained in its post. One of the project collaborators noted that the measurements could be pivotal for the field of asteroseismology, too.

[Related: Inside the tantalizing quest to sense gravity waves]

Meanwhile, the spectroscopy data breaks down starlight like a prism to reveal the contents, distance, and potential origins of the sun’s relatives. Gaia found primordial Big Bang material in some stellar signatures, along with an abundance of metal in denizens at the Milky Way’s core.

“Our galaxy is a beautiful melting pot of stars,” Alejandra Recio-Blanco, a galactic archaeologist at the Observatoire de la Côte d’Azur in France, said in a statement. “This diversity is extremely important, because it tells us the story of our galaxy’s formation. It reveals the processes of migration and accretion. It also clearly shows that our sun, and we, all belong to an ever changing system, formed thanks to the assembly of stars and gas of different origins.”

Watch the video below for a deeper dive on the new Gaia information—and a teaser of what’s next for the mission.

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Launching sometime in the next decade, NASA’s Gateway—a lunar outpost where Artemis astronauts will live and work as they orbit the moon—will help conduct in-depth science operations vital to humanity’s continued exploration of deep space.  

One such mission, called Hermes, or the Heliophysics Environmental and Radiation Measurement Experiment Suite, has recently passed a critical mission review, and NASA scientists will now transition into finalizing the mission’s design. 

“Hermes will be a critical part of the Artemis mission and NASA’s goals to create a permanent presence on the moon,” Jamie Favors, Hermes program executive at NASA, said in a press release on January 30. 

Built by NASA’s Goddard Space Flight Center, Hermes is one of two mini-weather stations that will monitor space weather with a focus on heliophysics, the study of the sun. The mission will examine dynamic conditions created by the sun, such as coronal mass ejections (CMEs) that can cause harm both to mission instruments and human activity. 

[Related: NASA is testing space lasers to shoot data back to Earth]

The station will be made up of four specialized instruments that will be placed together on one platform. One of them, called Nemisis, or the Noise Eliminating Magnetometer Instrument in a Small Integrated System, will measure the magnetic fields surrounding Gateway. 

Getting a better grasp on space weather phenomena through this mission will be helpful in preparing for future crewed expeditions. “In terms of human exploration, space weather is really about the radiation environment,” says William Paterson, project scientist for the Hermes mission. 

Scientists have been measuring space weather fluctuations on small scientific spacecraft for decades, but Hermes will be the first monitoring system on a crewed mission to gather data outside of Earth’s magnetic field—which acts as a radiation shield. This magnetic field, which extends about 60,000 miles into space, protects astronauts and the International Space Station from harmful radiation spewed out during events like solar flares and other galactic cosmic rays.

But as the moon orbits around the Earth, it passes in and out of the planet’s magnetotail, part of the field that is swept back by solar radiation. To get there, Hermes will have to fly through the Van Allen Belts—big swathes of energetic charged particles trapped by the Earth’s magnetic field. In lower orbit, astronauts aren’t usually affected by these belts, but if they were to fly at a higher altitude, this radiation could prove fatal over an extended period of time. 

Gateway will spend a quarter of its time inside this protective shield, giving researchers a rare opportunity to study and directly measure radiation from the sun. After launch, it will take about a year for Hermes to get into the right position to start its mission, which, if the journey goes as planned, will take place right after the peak of the sun’s current solar cycle. 

“Looking at the activity coming from the sun, it’s gonna be a really good time to get there and start doing our mission,” Paterson says.

In a separate payload, Gateway will also carry Hermes’ counterpart, ERSA, short for European Radiation Sensors Array. Both Hermes and ERSA were named after two of the goddess Artemis’s half-siblings in Greek Mythology. 

Although Hermes’ measurements will be used to ensure astronaut’s safety, its data is primarily scientific. On the other hand, the main focus of the European Space Agency’s ERSA will look at how solar wind radiation affects astronauts and their equipment.  

The daily data these stations send back will help create a clearer picture of how space weather operates around the entirety of our solar system. That information is especially important to know as humans venture towards creating habitable environments on, or near other planets. 

“We see this as kind of a pathfinder to help establish this capability that we think is going to be needed in the future to support exploration,” says Paterson. 

Hermes still has a long way to go before the scheduled liftoff in late 2024, giving ample time for the mission to undergo tests and changes. But Paterson is looking forward to the data that will be collected. 

Because most research into heliophysics is usually done in isolation, Paterson is interested in seeing this project expand humanity’s knowledge of how our star’s unique dynamics affect the rest of the solar system. 

“I think we’re going to be able to do really great science from the Gateway,” he says.  “There’s going to be a learning curve to figure out how to work around some of those challenges, but we’re pretty confident.”

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Many of us may feel like we’re living in a bubble, but Earth actually is residing in one. 

Published today in Nature, researchers from the Center for Astrophysics and the Space Telescope Science Institute have created a 3D map that reconstructs the evolutionary history of the “Local Bubble,” a 1,000-light-year-wide cavity of cold gas and dust that’s responsible for the formation of all nearby young stars—including our sun. 

The study reveals that Earth and all of the stars and star-forming regions within 500 light-years of the planet reside on the surface of this bubble, which is good insight, according to Catherine Zucker, astronomer at the Space Telescope Science Institute and lead author of the study. Learning more about how the Earth came to be inside the Local Bubble could be yet another definitive step in better understanding our galaxy. 

“Essentially we have a front-row seat to the all star formation that’s happening on the surface all around us,” Zucker says. But while astronomers have known about the Local Bubble for decades, this discovery wasn’t years in the making. In fact, it was an accident. 

“It actually started out because we just wanted to make a map of all the major landmarks, basically, in our galactic neighborhood,” she says. But what began as a typical foray into studying the spiral arms of the Milky Way, turned into a fantastic revelation after the team noticed that stars seemed to be unifying near the bubble’s surface. 

[Related: Astronomers just confirmed a new type of supernova]

By using a software program called Glue and data from the space observatory Gaia to create a map of where exactly these stars lie, Zucker’s team was able to determine that the bubble’s origin stems from a series of supernovae explosions that date back about 14 million years ago. These cosmic bubbles were created as interstellar gas was pushed outwards by the explosions, forming expanding shells that fragmented and collapsed into nearby molecular clouds.

“Think of the Milky Way as being shaped as a very thin pancake,” Zucker says. As supernovae go off in the center of the disk, the bubbles the reaction creates pokes holes on the surface of the “pancake,” and influences its structure. Multiple bubbles can touch and even collide with one another.  

Such a reaction is why the team’s results also assert that the Local Bubble’s structure isn’t actually bubble-shaped, but instead resembles a “galactic chimney.”

“We had to use data from a lot of different sources, but the most critical component was Gaia,” Zucker says. Launched in 2013 by the European Space Agency, the observatory surveys about 1 billion stars, or less than 1 percent of the stars in the Milky Way, in its mission to create the largest and most precise map of the galaxy. 

Without Gaia’s high-quality measurements, studying the intricacies of star formation in the universe would be a nearly impossible task. For reference, once all the datasets were collected, the team was able to create a working 3D model of the Local Bubble in about three hours. “If you know the 3D position and also 3D motions of these young stars, you can actually turn the clock forwards and backwards,” Zucker says.

By reconstructing the history of these star-forming regions, astronomers are able to see how these areas evolved over time. That knowledge will be instrumental in understanding the role dying stars have in creating ones, and what that means for the galaxy as a whole. 

[Related: Young galaxies transformed the early universe by blowing bubbles]

Adam Frank, a professor of physics and astronomy at the University of Rochester who studies the birth and death of stars, says that the Local Bubble is a “beautiful example” of how often triggered star formation—stars created by the blast of a supernovae—happens compared to other modes of formation. 

And although our planet didn’t inhabit the Local Bubble until about 5 million years ago, Frank says Zucker’s research led him to think about whether life on Earth was at all affected by the proximity of exploding supernovae. 

“One of the things that’s interesting about supernovae and hypernovae,” Frank says, “is that it’s possible that they can sterilize their local environments. It’s possible if you’re close enough, you can pretty much lose whatever life you have, or at least be affected by it.” Luckily, we know that Earth’s early primordial soup did indeed survive, but for some stars in our galaxy, death isn’t an end—it’s a rebirth. 

“The life cycle of stars is essential to understanding some of the things that we care most about,” Frank says. He says that it’s only through the recycling of the heavy elements they release and reform that Earth supports life at all. 

“We wouldn’t be here,” Frank says. “Life wouldn’t be possible without … silicon and iron, magnesium, calcium, and all these other elements, which are born inside stars.”

Correction (January 13, 2022): An earlier version of this story incorrectly stated the number of stars in the Milky Way galaxy Gaia space observatory surveys as 100 billion. The number is actually about 1 percent of the galaxy’s 100 billion stars, or approximately 1 billion.

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The Parker Solar Probe launched three years ago, with an ambitious goal to make ever-closer passes near the sun.

On April 28, the probe passed the Alfvén critical boundary, which marks the outer edge of the sun’s corona, where solar material ripples out in space after breaking free from the sun’s gravity and magnetic force. The Parker Solar Probe broke records by crossing that border, about 8 million miles from the visible surface of the sun. The probe’s passage into the sun’s atmosphere was confirmed in later analyses, and the findings were published December 14 in Physical Review Letters. 

The spacecraft entered the corona three times, according to the data—at one point for up to five hours. Once the probe passed the Alfvén critical boundary, “we saw the conditions change completely,” Stuart Bale, a physicist at University of California, Berkley and co-author of the paper, told BBC. “Inside the corona, the sun’s magnetic field grew much stronger, and it dominated the movement of the particles there. So the spacecraft was surrounded by material that was truly in contact with the Sun.”

To get readings of the sun without getting scorched, the Parker Solar Probe needs to move at over 320,000 miles per hour, making it the fastest object built by humans. It makes quick in-and-out dashes while its suite of instruments continuously take measurements from behind the probe’s heat shield, which protects the craft from intense radiation as the shield reaches temperatures up to 2,500°F (1,400°C).

That the probe entered and exited the outer corona multiple times proves researchers’ predictions that the outer corona is not a smooth sphere of plasma. Instead, it’s full of wrinkles, spikes, and valleys. Assessing how the shape of the corona aligns with solar activity can help astrophysicists determine the dynamics of features such as solar wind. 

[Related: Scientists just spotted a massive storm from a sun-like star]

At one point, the Parker Solar Probe got to about 6.5 million miles from the sun’s surface, encountering a feature in the corona visible during solar eclipses, called a “pseudostreamer.” There, “conditions quieted, particles slowed, and number of switchbacks dropped—a dramatic change from the busy barrage of particles the spacecraft usually encounters in the solar wind,” says a NASA statement. The space agency hopes to get Parker as close as 4 million miles by 2025. 

Astrophysicists also hope that flying by the sun will better reveal its inner workings. “Just as landing on the moon allowed scientists to understand how it was formed, touching the sun is a gigantic stride for humanity to help us uncover critical information about our closest star and its influence on the solar system,” Nicola Fox, the director of NASA’s heliophysics science division, told BBC.

Information we gather about the sun will also help astronomers understand stars at large, Anthony Case, the instrument scientist for the Solar Probe Cup, from the Center for Astrophysics | Harvard & Smithsonian, said in a statement. “The plasma around the sun can act as a laboratory that teaches us about processes taking place in almost every astronomical object across the entire universe.”

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The young star EK Draconis, which lies 111 lightyears from Earth, is about the same size and temperature as our own sun. However, it’s currently a much more turbulent place, a new report indicates.

Scientists observed EK Draconis as it hurled a burst of plasma into space that proved more massive than any previously recorded for a sun-like star. Our sun may have had similarly powerful storms in its past, which could have left their mark on Earth and its neighbors, the researchers concluded on December 9 in Nature Astronomy.

Our sun periodically gives off explosions of radiation known as solar flares. The flares are sometimes accompanied by eruptions of superheated matter, or plasma. These events are called solar storms or coronal mass ejections. Occasionally, the clouds of plasma reach Earth’s magnetic field to interfere with satellites and cause blackouts; in 1989, the entire power grid in the Canadian province of Quebec was taken out by a solar storm.

But our sun has calmed down a lot over its 4.6-billion-year lifespan, says Yuta Notsu, an astrophysicist at the University of Colorado Boulder and coauthor of the study.  Previous work by Notsu and his colleagues indicates that particularly impressive “superflares” are most common in young, rapidly rotating stars but may occur once every few thousands years or so on older stars like our sun.

“The sun is an average middle-aged, boring star; the flares aren’t really that energetic,” says Damian Christian, an astrophysicist at California State University Northridge who was not involved with the research. “We can study more active stars [and] we might apply what we learn from them to the sun.” 

Enter EK Draconis. The star is a sprightly 50 to 125 million years old and can offer a glimpse of what the sun might have looked like billions of years ago.

Notsu and his team observed EK Draconis from January to April 2020 using observations from ground-based telescopes as well as NASA’s Transiting Exoplanet Survey Satellite. On April 5, the star lit up with a large superflare. Shortly afterwards, the researchers detected a distinctive shift in the wavelengths of light picked up by the telescope. “From this we can conclude that a large amount of plasma is away from the star moving towards us,” Notsu says. 

He and his colleagues estimated that the plasma bubble was traveling at speeds up to roughly a million miles per hour and had a mass 10 times greater than the largest ejections from our sun.

[Related: Violent space weather could limit life on nearby exoplanets]

The researchers make a good case for the telescope observations being explained by a coronal mass ejection coming from EK Draconis, Christian says. “It’s a very nice result,” he says.

Although the findings are interesting, says Rachel Osten, an astronomer at the Space Telescope Science Institute and Johns Hopkins University, “What would be more convincing is multiple events…and maybe multiple methods that are showing these kinds of results.”

In the future, Notsu and his colleagues plan to search for more stellar outbursts and to track what happens to the plasma as it moves away from the surface of its star. “We only detected an initial phase,” he says. “We don’t know how it evolved.”

Still, he says, the coronal mass ejection that he and his team observed can help scientists understand how these storms unfold on distant stars and our sun. It’s possible that plasma erupted from the ancient sun damaged Mars’s atmosphere, which today is much thinner than that of Earth, Notsu speculates.

Stellar storms could have a big impact on whether a planet becomes habitable, Osten says. If the plasma reaches a planet’s magnetic field, its destructive effects can leave the atmosphere vulnerable to harsh ionizing radiation. 

Just because a blob of plasma is flung away from a star doesn’t mean that it’s going to hit one of the planets orbiting that star, though, Osten acknowledges. Still, she says, coronal mass ejections highlight how important it is to consider what goes on beyond a potentially Earth-like planet’s atmosphere when searching for alien life.

“This line of investigation is telling us that it’s all interlocked,” she says. “You can’t just focus on the planets, you’ve got to understand the stars because they’re an important ingredient in that recipe for what can make life.”

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NASA’s Parker Solar Probe is crashing through a hailstorm of dust as it hurtles towards the sun at awe-inspiring speed.

The probe’s team members found that high-speed impacts with dust particles are not only more common than expected, they’re making tiny plumes of superhot plasma on the surface of the craft, according to an announcement for a new study.

The probe’s main mission goals are to measure the electric and magnetic fields near the sun and learn more about the solar wind—the stream of particles coming off of the sun, says David Malaspina, a space plasma physicist at the University of Colorado Boulder Astrophysical and Planetary Sciences Department and Laboratory for Atmospheric and Space Physics. Malaspina led the study, which the team will present at a conference this week.

Scientists have studied the solar wind from a distance, Malaspina says, but “there’s a lot of fundamental questions about how the solar wind is born…that we really can’t answer using measurements only close to Earth.”

The probe is the fastest human-made object, currently traveling at over 100,000 miles per hour through the zodiacal dust cloud—the huge cloud of “the leftovers from asteroids and comets throughout the solar system” that are slowly falling toward the sun, Malaspina says.

The Parker Solar Probe wasn’t made to study dust. But, to get close to the sun and study the solar wind, it “plows right through the densest part of the zodiacal cloud,” Malaspina says. It can get a rough estimate of the dust’s density by tracking dust collisions. And with each orbit, the spacecraft  gets closer to the sun and speeds up. “Imagine driving into a sandstorm but doing it faster each time,” he says.

The mission team expected the probe would encounter dust, but without local measurements to rely on, they didn’t expect quite this much of it. On the previous orbit, the probe’s ninth pass around the sun, it got hit every twelve seconds on average, Malaspina says. If you could stand next to the spacecraft, you would see the holes in the spacecraft’s mylar protective coating, called a Whipple shield, he says. But so far, the shield has “held up against all impacts.”

[Related: NASA images show the sun has had a rough week]

Malaspina says the team is most worried about the cooling system, because the sun-facing part of the spacecraft can reach almost 2000°C. Water pipes run behind the heat shield and transfer the heat to radiators that dissipate it into space. Puncture one of those pipes and the spacecraft would definitely burn up, he says.

Building a craft that can survive this harsh environment “all comes down to choosing the right materials that you know are going to survive these impacts, and doing a lot of tests and analysis ahead of time,” says Jim Kinnison of the Johns Hopkins Applied Physics Lab, who is the mission system engineer for the Parker Probe. These tests include a hypervelocity impact chamber, Kinnison says, which can recreate space dust encounters by launching tiny, incredibly high-speed particles at materials here on Earth.

Although the dust grains near the sun seem to be more plentiful, they’re less massive than expected—luckily for the Parker Solar Probe—so the risk of serious damage to the spacecraft is still low, Malaspina says.

Despite their lightness, when dust particles hit the spacecraft with so much energy, Malaspina says, “they not only vaporize themselves, and a fraction of the spacecraft surface, but they also ionize it,” meaning they tear the electrons off their nuclei and create a tiny, short lived plasma blast with each impact.

Plasma has a strong electric charge, so these little spurts cause a spike in the electric field around the craft, which the spacecraft can measure.

Spacecraft have picked up these spikes before, but the plasma clouds around the probe are more intense than expected, Malaspina says. They are so dense that they noticeably interact with the solar wind, in a process that resembles the way the solar wind interacts with Venus, Mars, and other planets that lack a magnetic field. On those planets, sunlight ionizes part of the atmosphere, allowing the solar wind to sweep some of it away.

[Related: What happens when the sun burns out?]

The probe is continuing to move closer to the sun, into a region where scientists have long predicted that the intense solar heat has burned up all the dust. In fact, it’s possible the probe’s imaging team may have already observed this for the first time. Over the next few orbits, the spacecraft will get close enough to verify that finding with direct electric field measurements.

Despite these extreme conditions, the spacecraft is likely to survive until its planned destruction. Eventually, it will get so close to the sun that the probe will burn up and become part of the solar wind itself, which, Malaspina says, is “sort of a poetic ending.”

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The moon gets all the attention come Halloween, but this season the sun is giving us a scare—or rather, a flare.

On Thursday, a solar flare was recorded at its peak by NASA’s Solar Dynamics Observatory at 11:35 a.m. Eastern Time. The burst of energy caused a coronal mass ejection (CME), which is essentially a giant magnetic field fart. The light and particles from the CME will reach Earth this Sunday as a solar storm, but won’t physically affect humans or wildlife.

The space agency classified this flare as an X1, which is particularly raucous; the rating system runs from A, B, C, M, and X in terms of weakest to stronger, with numbers on top to show even more power. NASA once clocked an X28 in 2003. This is also the first X-class flare of the new solar cycle, says Kathy Reeves, an astrophysicist with the Smithsonian Astrophysical Observatory. A solar cycle is the 11-year period during which the sun’s north and south poles flip, affecting its magnetic field and solar activity.

NASA’s Solar Dynamics Observatory caught images of the flare and CME over multiple days this week. The particles looked like snow as they hit the detector, says Reeves.

Though solar flares and CMEs often correlate with one another and can occur simultaneously, they’re different phenomena. Both are caused by changes in the sun’s magnetic field that radiate out from its core. As the field ripples and realigns, it releases tremendous energy. This event can cause a great flash that scatters light: the solar flare. It can also hurl matter into space: the CME. The CME projects a swarm of magnetized particles out from a single spot on the sun’s surface. This cloud is known as “plasma.”

[Related: What happens when the sun burns out?]

Certain solar flares can interfere with radio communications. Sometimes airlines will divert flights set to travel over the Earth’s poles, because the sun’s electrons and energetic protons tend to amass near them and can disrupt the flight’s radio.

Solar flares can also make the Northern Lights go a little haywire, which could create a “spooky effect” this weekend, according to Reeves. “So you can see Northern Lights a little further South on Halloween,” she says. “That might be cool.”

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If you put a steamy cup of coffee in the refrigerator, it wouldn’t immediately turn cold. Likewise, if the sun simply “turned off” (which is actually physically impossible), the Earth would stay warm—at least compared with the space surrounding it—for a few million years. But we surface dwellers would feel the chill much sooner than that.

Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years. Millions of years after that, our planet would reach a stable –400°, the temperature at which the heat radiating from the planet’s core would equal the heat that the Earth radiates into space, explains David Stevenson, a professor of planetary science at the California Institute of Technology.

Although some microorganisms living in the Earth’s crust would survive, the majority of life would enjoy only a brief post-sun existence. Photosynthesis would halt immediately, and most plants would die in a few weeks. Large trees, however, could survive for several decades, thanks to slow metabolism and substantial sugar stores. With the food chain’s bottom tier knocked out, most animals would die off quickly, but scavengers picking over the dead remains could last until the cold killed them.

Humans could live in submarines in the deepest and warmest parts of the ocean, but a more attractive option might be nuclear- or geothermal-powered habitats. One good place to camp out: Iceland. The island nation already heats 87 percent of its homes using geothermal energy, and, says astronomy professor Eric Blackman of the University of Rochester, people could continue harnessing volcanic heat for hundreds of years.

Of course, the sun doesn’t merely heat the Earth; it also keeps the planet in orbit. If its mass suddenly disappeared (this is equally impossible, by the way), the planet would fly off, like a ball swung on a string and suddenly let go.

This article originally appeared in the November 2008 issue of Popular Science magazine.

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THERE’S PERHAPS nothing more ancient and unchanging than the sun, a yellow dwarf star that has illuminated Earth for over 4 billion years.

But our star, too, shall pass. And scientists are actually pretty certain about what will happen when it does. 

The sun powers itself by fusing, or combining, extremely hot hydrogen atoms inside its core. That creates helium and a lot of energy. But just as a music box will wind itself out, the hydrogen in the sun’s core will run dry. When that happens, in around 5 billion years, the sun will have to find a new power source. 

At first, that’s not a problem. Today, fusing hydrogen also lets the sun’s core push back against the outer layers pressing down. When the core can no longer hold out, hydrogen from those outer layers will flood in and heat up—giving the sun more fuel to fuse. All will seem well.

But this will come at a cost. The side effects of these events will cause the sun to redden, cool, and inflate to more than a hundred times its current size, swallowing the orbits of Mercury, Venus, and even Earth. The sun will transform into a red giant, just like the stars Arcturus or Aldebaran that we can see in our sky.

[Related: We still don’t really know what’s inside the sun—but that could change very soon]

It’s all for a fix of hydrogen that will only buy the sun an extra billion years of life. When that, too, runs out, the sun will be forced to reach for the next best thing: that helium it’s produced all this time.

When the sun begins to fuse helium, it might seem a return to normal. The helium will partly rebuild the ruins of the core, and the bloated star will lose much of its size. Astronomers call this the helium flash. But there’s a catch: The flash will burn off nearly a tenth of the sun’s perfectly good helium in mere minutes.

Afterwards, the increasingly geriatric sun faces a fatal problem: As fuel, helium just doesn’t compare to hydrogen. Fusing helium isn’t nearly as energy-efficient as fusing hydrogen, and it produces carbon and oxygen. It’s possible to fuse those, but it’s far more difficult and far more inefficient.

The remaining helium will only buy the sun another 100 million years or so.

When the sun can no longer fuse helium, it will enter another troubled time. It’ll puff back up, desperately flailing for any pockets of hydrogen or helium it can fuse. Even as the core starts to collapse, the star might push its outer rim ever farther away, maybe all the way past the asteroid belt.

This can only go on for so long. In the end, the sun will throw off all of its outer layers. Observers in the next star system might see a spectacular display, like a bright halo. For the sun we recognize, these 10,000 years are its moment of death.

It will leave behind a sort of celestial tombstone called a planetary nebula, even though planets aren’t involved—unless the dark, dead husks of what were once Jupiter, Saturn, Uranus, and Neptune manage to stop themselves from being blown away.

But for the sun, death is not the end. While about half its mass will flood out, the rest will crush together at the very center of the planetary nebula. This will turn into a tiny, bright, ultra-dense ember of the sun’s core, no larger than the Earth. This kind of smoldering remnant is called a white dwarf star.

So begins the sun’s long, last, lonely form. Over trillions of years, over a time that’s hundreds of times longer than the current age of the universe, that white dwarf will—very, very slowly—lose its remaining heat and fade to black.

This story originally ran in the Summer 2021 Heat issue of PopSci. Read more PopSci+ stories.

Is your head constantly spinning with outlandish, mind-burning questions? If you’ve ever wondered what the universe is made of, what would happen if you fell into a black hole, or even why not everyone can touch their toes, then you should be sure to listen and subscribe to Ask Us Anything, a brand new podcast from the editors of Popular Science. Ask Us Anything hits Apple, Anchor, Spotify, and everywhere else you listen to podcasts every Tuesday and Thursday. Each episode takes a deep dive into a single query we know you’ll want to stick around for.

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This story has been updated. It was originally published on July 24, 2013.

Of all the bodies in our solar system, the sun is probably the one we want to give the widest berth. It gushes radiation, and even though its surface is the coolest part of the star, it burns at about 9,940 degrees Fahrenheit, hot enough to incinerate just about any material. As such, there are no plans to send a manned mission in its direction anytime soon (Mars is much more interesting, anyway), but it can’t hurt to figure out at what distance a person would want to turn back. You can get surprisingly close. The sun is about 93 million miles away from Earth, and if we think of that distance as a football field, a person starting at one end zone could get about 95 yards before burning up.

That said, an astronaut so close to the sun is way, way out of position. “The technology in our current space suits really isn’t designed to withstand deep space,” says Ralph McNutt, an engineer working on the heat shielding for NASA’s Messenger, a new robotic Mercury probe. The standard space suit will keep an astronaut relatively comfortable at external temperatures reaching up to 248°. Heat coming off the sun dissipates over distance, but a person drifting in space would begin encountering that kind of heat (the five-yard line) some three million miles from the sun. “It would then be a matter of time before the astronaut died,” McNutt says. Above 248 degrees, the suit would transform into a close-fitting sauna—the temperature would climb above 125 degrees and the person would become dehydrated and pass out, eventually dying of heatstroke.

Riding in the space shuttle, though, someone could get much closer to our star. The ship’s reinforced carbon-carbon heat shield is designed to withstand temperatures of up to 4,700 degrees to ensure that the spacecraft and its passengers can survive the friction heat generated when it reenters the atmosphere from orbit. If the shield wrapped the entire shuttle, McNutt says, astronauts could fly to within 1.3 million miles of the sun (roughly the two-yard line). But the integrity of the shield degrades rapidly above 4,700 degrees, and the cockpit would begin to cook. “I would advise turning away from the sun well before that point,” McNutt says. Much hotter than that, the shields would fail altogether, and the vehicle would combust in less than a minute.

Of course, just getting that close to the sun would be quite an accomplishment, says NASA radiation-health officer Eddie Semones. The constant exposure to cosmic radiation during the voyage would most likely prove fatal before the astronauts crossed the 50-yard line.

This article originally appeared in the August 2010 issue of Popular Science magazine.

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What’s the weirdest thing you learned this week? Well, whatever it is, we promise you’ll have an even weirder answer if you listen to PopSci’s hit podcast. The Weirdest Thing I Learned This Week hits Apple, Anchor, and everywhere else you listen to podcasts every-other Wednesday morning. It’s your new favorite source for the strangest science-adjacent facts, figures, and Wikipedia spirals the editors of Popular Science can muster. If you like the stories in this post, we guarantee you’ll love the show.

This week’s episode is about all things hot—providing just a quick taste of the sorts of stories you’ll find in the latest issue of Popular Science. We’re now a digital-only magazine, which means you can access it right here and now.

FACT: Some skyscrapers are so shiny they turn into death rays

By Corinne Iozzio

In 2013, a London skyscraper known as the “Walkie Talkie” building made its mark on its neighborhood in an unusual way: Sunlight bouncing off the topmost floors of the bulbous facade melted cars on the street below. At the peak of its shine, the ray emitted 15 times as much solar radiation as would usually be found on the ground—enough to hurt any humans unlucky enough to cross its path.

Strangely, though, this was not the first time the so-called Fryscraper’s architect had set a town alight; the Vdara hotel in Las Vegas had, only a few years earlier, reflected rays so powerful they singed guests’ hair on the pool deck below. This was such a persistent problem that the hotel installed an army of giant umbrellas to shield swimmers and sunbathers. The Walkie Talkie now has a shield in place to provide a similar fix.

Many other buildings dotted around the globe have spurred similarly scorching scenes. Computer-assisted models have since revealed just how dangerous these rays can be, spurring physicists to sound alarms about the reflectivity of our modern structures—and implore architects to design buildings that sweat the exterior temperature as much as the interior one.

FACT: The sun will not explode in the year 2057

By Purbita Saha

Here’s some good news: We still have another five billion years before the sun runs out of hydrogen and sets us and our planetary neighbors on fire. That gives us a little more time than the sci-fi movie Sunshine predicted, and a couple of millennia to understand how stars truly meet their ends.

Astronomers have a pretty good guess at how the sun will burn out, based on the trajectories of yellow dwarves in other solar systems. But not all stars follow the same destiny. An energy analysis of distant galaxy NGC 6946 reveals that the red supergiant at its heart barely exploded as it completed its death spiral. Instead, it sort of just vanished and formed a gaping black hole, leaving its celestial neighbors intact. 

Experts are wondering if the red supergiant Betelguese will go out the same way. The grizzled star was looking dim in the night sky last year, but recent findings hint that it may have been due to a dust cloud, not impending nuclear doom. Tracking its fate and modeling more stellar scenarios could give us more insight on how our—and existence as we know it—will end.

FACT: If you love hot tubs, thank the Jacuzzis

By Rachel Feltman

When I set out to learn the history of the hot tub, the first, like, five pages of google search results were all from companies that sell them, which is absolutely my least favorite genre of history article. But then I found this amazing Atlas Obscura article from 2015 by Rich Paulas. You’ll have to listen to this week’s episode of Weirdest Thing to get the full scoop on my deep dive into the history of hydrotherapy—from the Ancient Romans, to bougie old resorts, to literal torture devices, to a bygone vestige of swinger culture, and finally to the fancy wellness aids we know and love today. But if you don’t learn anything else, know this: Jacuzzi isn’t just a product name. It’s also a surname. And the Jacuzzi family had a pretty prolific run as inventors during the first half of the 20th century. The next time you find yourself luxuriating in a whirlpool, take a moment to say salute to the Italian brothers who made your soak possible.

Plus: Click here for tips and tricks on how to take the absolute best and most relaxing bath ever.

If you like The Weirdest Thing I Learned This Week, please subscribe, rate, and review us on Apple Podcasts. You can also join in the weirdness in our Facebook group and bedeck yourself in Weirdo merchandise (including face masks!) from our Threadless shop.

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In the wee hours of the morning this Thursday, the moon will slide in front of our star to make the rising sun appear as a thin, fiery crescent. While only a lucky few in the icy North will get a full view of this event—known officially as an annular solar eclipse and lovingly as the ring of fire—stargazers in much of Europe and northern and eastern North America can still get a glimpse, if only partially.

The stars must literally align for this rare event to take place. The moon needs to be in its first lunar phase, also known as a new moon. It also has to be at its farthest point from Earth, making it appear smaller in the sky. These circumstances are what allows the edge of the sun to peek out around the moon and form the iconic ring of fire, appearing as a dark disk surrounded by bursts of light. In places where only a partial eclipse is visible, that darker disk will only appear to cover a section of the sun. 

To see it, look east along the horizon before, during, and just after sunrise to experience the ring of fire. Make sure you have an unobstructed view of the horizon, ideally on a body of water. This way you may even be able to see the so-called “devil’s horns” of the sun, the two points of crescent-appearing sun peeking above the horizon. 

People in remote parts of Canada, Greenland, and northern Russia will be the only ones able to see the full ring of fire. Check out this guide from the National Science Foundation to figure out if you’ll be able to see the event.

This event is different from a total solar eclipse, where the sun is completely obscured by our lunar neighbor. You might remember the last total solar eclipse from summer 2017, when the phenomenon captured America’s attention. 

Through all this celestial excitement, it’s crucial to remember that you should never look directly at the sun, even just for a partial eclipse. If you don’t have eclipse-safe glasses (not just regular sunglasses!) ready to go for the big day, check out our guides to making your own eclipse projector instead.

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Shortly after sunset on June 18, 2013, a woman drove her minivan onto Brighton Street in Belmont, Massachusetts. Her GPS told her to turn right. But the metallic voice, guided by satellite data, steered her wrong: onto a railroad track. She tried to drive off, but the van got stuck. No sooner had she ­unbuckled herself and her two kids and ushered them out than a train crumpled her car into a ball of foil. Not long after, someone sent a news story about the incident to space physicist Tamitha Skov. She didn’t just see a GPS acting up. She saw the sun acting up. While our star looks calm and contained, its ­surface roils: Spots form and darken it like scabs; loops of plasma link its regions; its atmosphere streams farther outward than the star is wide. Solar flares, which are bursts of radiation, and coronal mass ejections, which are bombs of stellar material, disturb both Earth’s magnetic field and upper atmosphere. There, they disrupt devices—like GPS ­receivers—that rely on electricity or radio communication. This interplay between the sun and Earth is called space weather, and it is Skov’s specialty. At the time, Skov had just begun a Web ­video series that gave space-weather ­forecasts, much like the predictions Al Roker makes on TV for clouds and sunshine. In it, she explained how our nearest star affects Earth. She had a modest but engaged following. Motorists were already starting to tip her off whenever their SiriusXM service cut out, airline and small-craft pilots would tell her when navigation went awry, and taxi drivers would describe routing errors. A number of these accounts involved drivers rolling, at the behest of their GPS, onto train tracks, or other not-roads, especially near dawn and dusk. At first, Skov blew off these anecdotes. When the reports kept coming, she ­consulted an atmospheric expert at the ­Aerospace Corporation, a federally funded R&D center where Skov works as a research scientist. “What’s up with this?” Skov asked her colleague. “Is it something?” Yes, the woman replied, the atmosphere is always unstable at sunset and sunrise. Add solar flares to that? “It could definitely make a difference,” the expert said. Skov checked the website of the Lockheed Martin Solar and Astrophysics Laboratory to see if there had, in fact, been a solar flare around the time of the ­woman’s fateful drive. And there it was: a C-class ­outburst, medium strength.

No single small solar event—like this C-class flare—can yet be definitively linked to a specific problem, like a GPS device in a minivan leading its driver onto railroad tracks. Skov nonetheless calls incidents like this one smoking guns, even if scientists can’t conclusively prove the cause. She strives to make people aware that this kind of thing can happen. “I was trying to impress upon people that GPS is extremely susceptible,” she says of the van accident, “and just blindly trusting it is nuts.”

Space weather’s effects can be small or significant. The C-class solar flare was hardly noticeable, even if it did total the woman’s car. But there is also plenty of evidence that humans need to watch out for the sun—­big-time. So Skov dedicated herself to explaining the increasing terrestrial problems that will come from the star that lets us live on Earth in the first place. She became the Space Weather Woman, connecting her viewers to the cosmos and bringing all levels of space weather to all kinds of people.

Stormy weather

The last time the sun really made people go uh-oh was on March 10, 1989. Astronomers watched as the star set loose a billion tons of gas at a million miles an hour—a coronal mass ejection—and blasted a solar flare along with it. The radiation, traveling at light-speed, struck Earth eight and a half minutes later. As it collided with the upper atmosphere, it charged up molecules, blocking radio ­communications at Earth’s upper latitudes, including from Europe into Russia, which at the time, listeners took as Cold War interference. The radio-frequency problems mostly affected ground-to-air and ship-to-shore communications, as well as shortwave-radio and amateur radio users.

The real problems came two days later, when a slower-moving swarm of magnetically charged material arrived. It pummeled Earth’s magnetic shield, which protects the globe from everyday radiation. Charged particles whizzed down magnetic-field lines and smashed into atoms in the air, ­producing Northern Lights. Usually those stay, you know, up north. But this time, the show played as far south as Texas. Satellites lost their bearings and tottered as particles bombarded their electronics. The storm stripped the GOES-7 weather satellite of half its solar cells, ­shortening its lifetime by 50 percent.

Earth’s shivering magnetic field also ­created ground currents. Coursing along, they encountered a flaw in Quebec’s power grid. It was easier for the current to flow through the power lines than across the rocky ground, and the extra load caused circuit breakers to trip. Around 3 a.m. on March 13, the whole province went dark.

It’s Quebec: It was cold—5 degrees ­Fahrenheit in some places. There was no heat. Schools and companies closed; public transit and the airport went still. The outage affected 6 million people for up to nine hours.

Today, modern society relies on exactly the devices that such a storm disrupts. A 2017 study in the American Geophysical Union’s Space Weather journal estimated the effect if a solar storm as great as the largest on record—an 1859 shakeup called the Carrington Event—were to strike again. It would cost the United States $42 billion per day. The repercussions could last years, perhaps decades. The power grid could fail. You wouldn’t be able to get money out of a bank. Businesses couldn’t operate. Water pumps wouldn’t work; phones either. Food would go bad. Governments would have a hard time governing. “We have created an incredible vulnerability, unlike any other,” says Bill Murtagh, program coordinator for the Space Weather Prediction Center, the celestial arm of the National ­Oceanic and Atmospheric Administration, headquartered in Boulder, Colorado.

Solar disturbances were largely the ­concern of academics until 1994, when the federal government created the National Space Weather Program to support research into the storms. In 1996, scientists held the first space-weather workshop in Boulder. Since 2007, they have been meeting annually to discuss the latest research. Their reports, as well as ones from private industry, eventually alarmed the Obama White House, which in 2014 established a task force to devise a defensive strategy, coordinate government agencies and the private sector, and increase the quality of space-weather predictions.

There is a greater than 10 percent chance that a Carrington-scale event will ­happen within the next decade, according to a ­paper by Pete Riley of Predictive Science, a space-weather research company. That might sound like a small number, but it’s higher than the chance of a major ­earthquake hitting California.

Scientists like Murtagh and Skov follow the sun’s activity daily, so they see how it fiddles with tech in ways most of us fail to register. It is precisely because of that familiarity that they understand how serious even ­another Quebec-size event would be. Skov wants regular citizens to gain the same perspective. That’s why, under the alter ego of the Space Weather Woman, she details for them the ups and downs of the sun’s violent outbursts.

Skov has outfitted a DIY recording studio in her home in the San Fernando ­Valley, just far enough north of Los ­Angeles that you begin to think that maybe you’re somewhere else. At the end of a road steep enough to require using a parking brake, she’s a little closer to the sky than her neighbors. This fall morning, she’s been working on a new video about why people should care about how the sun’s behavior affects humans.

Skov stands in front of a big monitor paused on a frame showing Twitter statistics. We live, she says, in a brave new(ish) world. A solo space physicist can start her own branch of meteorology from a room right off her driveway. And she can also gather information—about aurorae, radio-communication problems, and GPS errors—from a global community.

She moves away from the monitor and ­toward her camera. A green screen hangs from the wall to her right. The room shines with synthetic illumination: A ring light—like a luminous Life Savers candy—encircles the camera; across the room, a warmer bulb beams against a drugstore umbrella spray-painted silver.

The studio dates to her grad-school days, when Skov studied space physics at UCLA, was part of a pop alternative rock band, and ran a production company recording other musicians. After she graduated, she kept the studio going as she started work at the Aerospace Corporation, which gives guidance to the military, space agencies, and the private sector on research and development and technology transfer. There, Skov studied space weather’s interactions with satellites. “I was beginning to get this big picture,” she says. “This isn’t ‘space weather’ as a cool term. This is space weather.” Outside her professional life, she pivoted from audio to video production.

All of it spun together in 2012, as she grew concerned about the sun’s threats. She took to Twitter, where people had questions—lots of them. And Skov had answers, sans jargon. “You put three words that are from the space-science field on Twitter, and you already walked all over your character limit,” she says. Soon, she began producing short videos and putting them on YouTube. Then came the nickname and her likeness superimposed on the sun: the Space Weather Woman. The style reads as intense: close-cropped shots of the sun’s flares that make the viewer feel less like it’s a mysterious object 93 million miles away and more like it’s right there with her—and so with them.

Initially, Skov kept her two identities ­separate. She used her married name in her forecasts and her maiden name on scientific papers. She thought the slimmed-down ­science might slam into the research community at the wrong angle. But peers found her anyway after a space physicist discovered her videos and sent them to a researcher listserv. Some scientists pointed out small inaccuracies. Others simply didn’t like her “loosey-goosey” language, which didn’t use their jargon, with its specific but impenetrable meanings. She took the legit criticism—it kept her honest, she says—and left the rest. “I think I’d rather be pelted with olives from scientists than pelted with olives from the public,” she says. Now, researchers too watch her forecasts, along with 27,000 Twitter followers and 11,000 YouTube subscribers. “There is really nothing like it around,” says Christian Moestl, a space-­weather scientist at the Austrian Academy of Sciences. “Her YouTube videos and Twitter feed are watched by both researchers and ­interested public to see what’s going on.”

Skov’s biggest fans are in the amateur-­radio community: people with handsets and ham licenses. Radio operators see space weather scrape across Earth in real time when their broadcasts get blocked or enhanced. Amateur radio operator Tom Crow first found her forecasts on a program called Ham Nation.

“Dr. Skov has a knack for explaining terms in detail without the feeling that it’s been dumbed down.”

Then there are the aurora tourists. Skov’s forecasts tell them where to go when. But that charge flows in both directions: Field reporters also tell Skov where the aurora is showing up. “People started informing each other, and the community began to build,” she says.

Skov believes that understanding how life on Earth is looped inextricably with our star can help people grok the import of the really, really big one. She draws a comparison to more-familiar weather forecasting. Humans grow up hearing about meteorological phenomena great and small. But that doesn’t happen with space weather. “It’s like trying to tell someone who’s never seen rain how dangerous a hurricane is,” she says.

Once people understand, they can ­prepare for extreme space weather as they do for any natural disaster: Have ­water supplies, extra gasoline, and nonperishable food, and make a plan for meeting up even if you can’t communicate. And have some board games, because this might take a while.

Threat level

As the Space Weather Woman, Skov is at the vanguard of interpreting data from NASA satellites and observatories for regular folks. But when big entities like satellite operators, energy companies, and airlines need to know how the sun’s shine will affect them, they turn to the Space Weather Prediction Center, whose scientists scrutinize the data, looking for activity strong enough to cause friction with earthly objects.

Any time that happens, they send out alerts—categorized from one to five, with five being the highest—to utilities, satellite companies, and others. Toward the end of 2017 they did that around 100 times a month. With a warning, technicians can reroute electricity, reschedule communication, and delay satellite operations.

When the sun carries on in a big way, a subset of the scientists relocates to the High-Activity Room, a sealed-off spot where they talk with major players. There, the ­Federal Emergency Management ­Agency has its own internet-enabled video-­conferencing monitor, labeled like ­leftovers in an office refrigerator. FEMA needs to know what’s coming so it can prepare for the disruption a major power outage would cause, and to coordinate with operatives before a communications blackout occurs.”Communication is life or death,” Murtagh says.

In September, rescue workers got a taste of what it is like when the sun and Earth both create hurricanes. Just as Irma battered land, the sun sent out a series of flares and coronal mass ejections. High-frequency radio ­comms ceased in the storm-battered Caribbean. Hurricane Watch Net, made up of amateur radio operators, reported disruptions.

While this confluence didn’t add to the destruction, it could next time, especially as earthly storms come with more frequency and force, and are thus more likely to line up with a starburst. Just like with a Category 5 hurricane, there’d be no getting around a major solar event. All we could do is see it coming, get a sense of how bad and big it would be, and prepare to hunker down for a while.

Soon the Space Weather Prediction Center will gather the data to make more-precise predictions, with the launch this year of observatories like NASA’s Parker Solar Probe, which will fly closer to the sun than anything so far, and two additions to the sun-and-Earth-watching GOES satellite series in 2018 and 2020. Its scientists have also created a model that will make local space-weather reports possible. “The AccuWeathers of the world can take the information and make a tailored product,” Murtagh says.

Those space AccuWeathers are only in their infancy, but Skov can’t wait for them—and for the broadcasters and predictors and translators who will bring our star down to Earth for people. She’s working with the American Meteorological Society to create a space-weather-broadcast certification. She might be her discipline’s version of Al Roker, but even Al Roker needs local forecasters, standing in front of their own green screens, giving that quotidian space-weather report to a curious audience. “You say, ‘Imagine 10 to 100 times worse than this,’” she says. “And they go, ‘My god.’ It hits them. And they go: ‘I get it. I really get it.’”

Contributing editor Sarah Scoles is the author of Making Contact: Jill Tarter and the Search for Extraterrestrial Intelligence.

This article was originally published in the January/February 2018 Power issue of Popular Science.

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If you put a steamy cup of coffee in the refrigerator, it wouldn’t immediately turn cold. Likewise, if the sun simply “turned off” (which is actually physically impossible), the Earth would stay warm—at least compared with the space surrounding it—for a few million years. But we surface dwellers would feel the chill much sooner than that.

Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years. Millions of years after that, our planet would reach a stable –400°, the temperature at which the heat radiating from the planet’s core would equal the heat that the Earth radiates into space, explains David Stevenson, a professor of planetary science at the California Institute of Technology.

Although some microorganisms living in the Earth’s crust would survive, the majority of life would enjoy only a brief post-sun existence. Photosynthesis would halt immediately, and most plants would die in a few weeks. Large trees, however, could survive for several decades, thanks to slow metabolism and substantial sugar stores. With the food chain’s bottom tier knocked out, most animals would die off quickly, but scavengers picking over the dead remains could last until the cold killed them.

Humans could live in submarines in the deepest and warmest parts of the ocean, but a more attractive option might be nuclear- or geothermal-powered habitats. One good place to camp out: Iceland. The island nation already heats 87 percent of its homes using geothermal energy, and, says astronomy professor Eric Blackman of the University of Rochester, people could continue harnessing volcanic heat for hundreds of years.

Of course, the sun doesn’t merely heat the Earth; it also keeps the planet in orbit. If its mass suddenly disappeared (this is equally impossible, by the way), the planet would fly off, like a ball swung on a string and suddenly let go.

Send your questions to fyi@popsci.com. Can’t wait a month? Look for answers on our Web forum, popsci.com/fyilive.

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Moon-shaped

Today, we’re able to get even more specific, thanks to our understanding of the shape of the moon. The moon—contrary to every elementary-school drawing you ever labored over—is not in fact, shaped like a banana or a perfect sphere. Like the Earth, it has mountains and valleys that make its shape a little rough around the edges, and that means that it’s shadow is uneven as well.

In the from the late 1940’s until 1963, an astronomer named Charles Burleigh Watts spent countless hours mapping out the variations that appeared on the moon’s surface, focusing on the landforms that appeared on the outer edge of the moon as seen from Earth. His detailed maps helped eclipse predictions get even more precise. Then, NASA took it up a notch. NASA’s Lunar Reconnaissance Orbiter built on Watt’s work, and captured the topography of the moon in detail that would have been impossible to get from photographs of the moon taken on the ground.

NASA visualization expert Ernie Wright took that data about the shape of the moon, the topography of the Earth, and the positions of the sun, moon and Earth to create an incredibly detailed and accurate accounting of where the eclipse shadow will pass across the United States.

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Humans have long dreamt about looking directly at the Sun, even though it’s extremely dangerous for our peepers. Our nearest star is the centerpiece of religious and cultural traditions all over the world, from Ra in ancient Egypt to the sun goddess Amaterasu in Japan and the sun god Inti in the Incan Empire. Even as humans started building telescopes to look into every corner of the Universe, the Sun remained elusive. Only until earlier this year were we able to capture, for the first time ever, detailed images of the sun’s boiling surface. This week, the first image of a sunspot from the high-definition Inouye telescope was finally published.

Researchers at the world’s largest solar observatory, the U.S. National Science Foundation’s Daniel K. Inouye Solar Telescope, captured the image. It’s located on top of Haleakalā, a sacred mount for the Native Hawaiian peoples of the island of Maui.

“We can now point the world’s most advanced solar telescope at the Sun to capture and share incredibly detailed images and add to our scientific insights about the Sun’s activity,” said Matt Mountain, president of the Association of Universities for Research in Astronomy (AURA) in a press release.

Understanding the Sun’s activity has always been challenging. Astronomers have a clear idea of how solar storms—waves of electrons, protons, and atoms the sun shoots toward our planet—affect human technologies like power grids, communications, GPS navigation, air travel, and satellites. They also know how the internal processes of the boiling star create the bubbles that ultimately generate those violent energy spill-overs. But the details to predict when the blobs will explode, and how often it’ll happen, are still largely unknown. And that information would be useful—we could prepare for losing things like GPS in advance.

“On the sun we have some photos, a few extrapolations, and then there’s a lot of guesswork,” Dan Seaton said to PopSci earlier this year. The Daniel K. Inouye Solar Telescope (DKIST) is the largest effort to answer those questions. The $344 million facility takes images with as much as 2.5 times the resolution of previous images taken by other telescopes, capturing areas of the sun as tiny as 12.4 miles in diameter in full detail.

This recent sunspot image was captured on January 28 of this year, and it’s just one part of a bigger series. To capture the sunspot, the researchers pointed the telescope’s 13-foot mirror—three times wider than any other solar telescope—towards the central area of the star. They captured a sunspot of about 3,700 miles across, just a tiny part of the Sun, but large enough to fit almost half of Earth inside it.

The sunspot is about 7,500 degrees Fahrenheit—pretty cool compared to the most extreme temperatures of the sun’s surface, which get up to 10,000 degrees. The combination of intense magnetic fields and hot gasses boiling up from below the surface creates the streaky appearance in the image, as hot and cool gas spiders out from the darker center, said the NSO in a press release.

This sunspot also marked the beginning of a period of activity on the solar surface that’ll reach its peak activity in 2025, according to the team’s best predictions. “This image represents an early preview of the unprecedented capabilities that the facility will bring to bear on our understanding of the Sun,” said in a press release Dr. David Boboltz, NSF Program Director for the Inouye Solar Telescope. The time when humans look directly at the Sun—at least with a giant telescope—has finally arrived.

Correction, 1/28/21: This article previously misstated the size of the Earth in comparison to the size of the sunspot. Only roughly half of Earth could fit inside.

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When the sun warms your face, it’s shooting more than just sunbeams at your skin. Neutrinos—ghostly particles with just a trace of mass—come along for the ride. Many trillions of them enter your body each second and carry right on into the ground, whizzing through the planet at nearly the speed of light.

Scientists have spent years scrutinizing this barrage of neutrinos, trying to understand precisely how the sun makes and launches them. While 99 percent of the sun’s energy comes from one type of fusion, the remaining one percent has long been thought to come from a second, more complicated reaction. And after decades of experimental wizardry, physicists have detected the neutrinos coming from this rarer reaction for the first time.

“This represents a smoking gun,” says Marc Pinsonneault, an astronomer at The Ohio State University who was not involved. It’s “a really beautiful confirmation of a very deep theoretical prediction.”

In those modest handfuls of neutrinos, researchers hope to eventually discern the answer to one of astronomy’s more heated questions: what ingredients make up the sun, and by extension, all the other stars in the universe?

Researchers know that the sun is at least 98 percent hydrogen and helium, nature’s two lightest and most abundant elements. But debate rages over the makeup of that final two percent. Astronomers usually figure out what objects are made of by analyzing which colors of light they emit (or don’t emit), but when it comes to some of the sun’s heavier ingredients—such as carbon, nitrogen and oxygen—their fingerprints just don’t shine through clearly.

“The problem isn’t the data,” Pinsonneault says. “It’s an accident of the periodic table.”

When observations fell short, researchers turned to theories. Early models predicted that the sun should be 1.8 percent bulky atoms such as carbon, nitrogen, and oxygen. But then in the 2000s, more sophisticated theories incorporating the sun’s churning and other features predicted that just 1.4 percent of the star should be heavyweights.

Half a percent difference might not sound like much, but it has cosmic consequences. Since the sun is the best-known star, astronomers use it almost as a unit of measurement. Another star of similar appearance, they assume, should have the similar composition. And when you multiply by all the stars in the universe, half a percent adds up fast. If the lower estimate is correct, for instance, that would cut researchers’ estimate for the amount of oxygen in the entire cosmos by 40 percent.

“When you change the sun, you change how much [heavy stuff] we think there is everywhere,” Pinsonneault says.

One way to really get a handle on what’s going on inside the sun is to study the countless neutrinos that it blasts through Earth every second. In our star, the vast majority come from the direct fusing of protons. But nuclear physicists predicted in the late 1930s that a few should originate from a complicated reaction where precisely the heavy elements in question—carbon, nitrogen, and oxygen—help guide protons together.

The hunt for the so-called “CNO neutrinos” began in 1988. All nuclear reactions spray neutrinos, so if you’re looking the few that come from a rare nuclear reaction millions of miles away, first you have to prepare a squeaky-clean nuclear environment. Members of the Borexino collaboration in Italy started by developing the technology to purge the materials from which they would build their detector of polluting radioactive ingredients. The effort took 19 years.

“It is probably the purest environment in terms of radioactivity on Earth,” says Gioacchino Ranucci, a Borexino member.

Even then, the detection didn’t come easily. The researchers built Borexino deep under a mountain, away from cosmic rays, in Italy’s national laboratory at Gran Sasso. A three-hundred-ton chemical brew forms the core of the detector—which flashes on the extremely rare occasion that a neutrino interacts with the liquid. Another 1,000 tons of the same concoction envelops the core of detector, and 2,300 tons of water surround the whole apparatus, shielding it from gamma rays and neutrons spit out by the rocks of the Gran Sasso mountain.

The experiment switched on in 2007, detecting neutrinos from the sun’s main type of fusion almost immediately. Over the next few years, researchers probed every aspect of the standard proton-proton fusion. CNO neutrinos, however, remained out of reach.

In 2015, they revamped the detector to keep the liquid in the core completely still, and, finally, their efforts have paid off. In June, the international collaboration of about 100 researchers announced that after eliminating all other possible sources they were at last detecting CNO neutrinos. Each day, the central 100 tons of liquid flashes about 20 times on average. Ten come from radioactive decay in the detector materials, and in this particular energy range about three come from the sun’s main fusion reaction. The remaining seven flashes, Ranucci says, mark the arrival of neutrinos launched by the sun’s rare instances of CNO assisted fusion. The team published their results today in Nature.

“This is a beautiful, beautiful experiment,” Pinsonneault says.

Taken together, those seven daily flashes give the slightest of hints that the sun—and therefore the universe—might have more carbon, nitrogen, and oxygen rather than less. But even after decades of toil and a tour-de-force measurement, the evidence is not conclusive. “We have a preference for high [abundances of heavy elements],” Ranucci says, but “it could be a fluke.”

The Borexino experiment will continue to search for flashes of CNO neutrinos for a few more months, after which the lifetime of the detector will end. Ranucci looks forward to publishing one more CNO neutrino paper with an additional year and a half of data, which may offer a somewhat firmer answer.

Regardless of how much the Borexino collaboration can squeeze out of the machine’s final days, Pinsonneault says that solar physicists are working on additional experiments that might get at the sun’s contents in other ways. And, failing that, even bigger vats of liquid are on the way. None are yet taking data, but after decades of watching Borexino’s development, solar physicists are accustomed to being patient.

“It does not close the door on one or the other branches of the solution, Pinsonnault says, “but it does point the way toward future generations that may be more decisive.”

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Picture a pair of collapsed stars, light-years away, locked in a “dance” of death: a final embrace that will end in their collision. In about 500 million years, astronomers anticipate this exact scenario will play out in a system known as PSR J1913+1102. Two neutron stars will crash together, sending a shudder through the universe: the fabric of space and time will ripple in the form of gravitational waves.

Most binary systems include two comparably sized neutron stars locked in a fiercely tight orbit. But PSR J1913+1102 contains a pair of mismatched neutron stars — one of them a pulsar — with masses that are 1.62 and 1.27 times the mass of the Sun. That makes it “the most asymmetric merging system reported so far,” according to a study published Wednesday in the journal Nature detailing the system and its impending collision. 

This rare, lopsided star system offers a unique opportunity to solve some of the universe’s most elusive mysteries, like how fast the universe is flying apart.

All other double neutron star systems we’ve found that are set to merge have all had stars of almost exactly equal mass, says Collin Capano, a researcher at the Max Planck Institute for Gravitational Physics who was not involved in the study. “This [new] observation is going to force us to rethink some of the assumptions we’ve made about how neutron-star binaries are formed, while also raising new questions for us to answer.”

Neutron stars are the ultra-dense smashed up remnants of long-ago supernova explosions. A pulsating neutron star is named, appropriately, a pulsar. These stars spew out visible cosmic fireworks as they rotate — like the beam of a lighthouse — that are ultimately detected as pulses of light by radio telescopes back on Earth.

By recording the precise timing of the pulses, researchers like Robert Ferdman, a physicist at the University of East Anglia and lead author of the study, can even predict future pulses.  “By doing that, we can actually keep track of the rotations of the neutron star which can help us use them as “clocks” in order to determine various things — like [star] masses,” Ferdman says.

An international group of scientists, led by the University of East Anglia in the United Kingdom,  relied on data collected by the Arecibo Observatory in Puerto Rico as part of a large-scale survey of the galactic plane. The new study estimates that other stellar odd couples like PSR J1913+1102 are out there; more than 1 out of every 10 of the total population of neutron star mergers is asymmetric.

This finding can help us better understand past astronomical events, too. Back on August 17, 2017, we saw a watershed moment in the history of astronomy. Researchers throughout the world witnessed the cataclysmic crash of two ultra-dense neutron stars some 130 million light-years away using Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo, its Italian sister detector. Known as GW170817, the spectacular event wasn’t surprising, but the enormous amount of matter the collision released — around five times higher than expected — remained a mystery. 

While the two merging objects weigh together about 2.8 times that of the Sun, the individual masses of the two neutron stars are not known. GW170817 can be explained with other scenarios, but researchers say it’s possible the unexpected ejected material was due to a merger of objects with very different masses, like the pair in this week’s Nature study. “When the gravitational effects of the more massive star rips apart the less massive one, it will cause lots more stuff to be thrown out into space,” Ferdman says.

Vicky Kalogera, an astrophysicist in the LIGO Scientific Collaboration who was not involved in this study, says the result is very exciting. Not only does the discovery “beautifully” fit with the spectacular GW170817 event, she adds, but it’s a relief that other asymmetric systems like PSR J1913+1102 are out there.

Detecting these kinds of binary systems can also help determine how fast the fabric of the universe is expanding — a much-contested number called the Hubble constant. 

Pinning this number down tells us a great deal about the origin, age, evolution, and ultimately the fate of the cosmos. And yet, the two most precise ways of measuring it — looking at the light from nearby flashing stars and the oldest observable light in the universe — are at odds with each other, with a curious 8 percent discrepancy. A third independent method of calculating the Hubble constant could help bridge that divide, and Ferdman and his colleagues hope that asymmetric mergers may be key. “It could help break the deadlock,” he adds. 

Neutron star collisions are also the ultimate cosmic alchemist, cooking up the heaviest elements in the universe like gold. Though astronomers and physicists have marveled at these stellar corpses for decades, the innards of neutron stars are not completely understood. Massive collisions of neutron stars, especially asymmetric ones, may allow scientists to gain important clues about the exotic matter that makes up the interiors of these extreme, dense objects.

Hard answers for all these cosmic queries will come only with more detections. In the meantime, Ferdman and his colleagues hope to use PSR J1913+1102 as a far-flung laboratory to test our understanding of gravity. 

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Boring. Humdrum. Monotonous. Those aren’t words most of us would usually associate with the miasma of incandescent plasma that makes life as we know it possible, but a recent study suggests that, as far as sun-like stars go, our own sun is a bit of a layabout.

In a study published this week in the journal Science, researchers compared our sun to 369 stars deemed similar to the one at the center of our own solar system—ones that take between 20 and 30 days to rotate on their axes, along with having comparable chemical compositions, masses, ages, and surface temperatures. Each of the studied stellar bodies had been observed by NASA’s Kepler Space Telescope from 2009 to 2013, allowing the researchers to compare fluctuations in brightness during that period.

“We were very surprised that most of the sun-like stars are so much more active than the sun,” study author Alexander Shapiro of the Max Planck Institute for Solar System Research said in a statement. The other stars showed around five times the brightness variability displayed by the sun during the same period. That could mean our host star is unusually tame for its type—which could be quite a good thing for us.

A star appears to dim when it has more sunspots, which are areas of temporary coolness in surface temperature. A sunspot happens when a star’s magnetic field is so strong that it keeps heat trapped deep below. While sunspots themselves are relatively cold and dark, their presence indicates that a star is making quite a ruckus. They mean the magnetic fields caused by the star’s electrically charged gases are particularly strong, and so are more likely to cross and interact in ways that cause solar flares. When our sun lets out these intense bursts of radiation, they can collide with Earth’s own magnetic field—forming aurorae (the Northern and Southern lights) if we’re lucky, and interfering with our electrical grids and GPS systems if we’re not.

Big bursts of cosmic radiation don’t make life easier for anyone, so it’s possible Earth has benefited greatly from the sun’s relative laziness.

“A ‘too active’ star would definitively change the conditions for life on the planet, so living with a quite boring star is not the worst option,” lead author and Max Planck astronomer Timo Reinhold told Reuters.

But was our sun born this dull, or is it just going through a phase of malaise? In addition to good records of sunspot activity going back several hundred years, scientists have used traces of radioactive elements in tree rings and ice cores to estimate the sun’s activity going about 9,000 years back—and we know its doldrums have lasted at least that long.

“However, compared to the [4.6 billion-year] lifespan of the sun, 9,000 years is like the blink of an eye,” Reinhold said in a statement. That means it’s technically possible that the star will perk back up at some later date, but the study authors suspect a different explanation: The sun is getting on in years, and life on Earth has benefited greatly from its dotage.

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When astronomers look out into the galaxy, they find that many star systems fall into one of two types: alive or dead. There are plenty of healthy yellow and red stars hosting planets, not so unlike our solar system. And then there are “dead” white dwarf stars—future versions of our sun—many of which feature disks of dust, gas, and shattered debris. How does a dying star reduce the first system to the second? In part by pulverizing its asteroids with next-level sunlight, recent research suggests.

When the sun someday balloons into a red giant, swallowing Mercury and Venus whole and scorching Earth will be just its first step in transforming the solar system. Because it’ll grow so much larger, our star will also flood space with thousands of times more light than it currently does, like swapping out a lamp for a searchlight. One of the most dramatic effects of this energy abundance will be to spin asteroids into pieces, suggests a recent publication in the Monthly Notices of the Royal Astronomical Society. The phenomenon could explain why astronomers see so many mini-asteroids falling into white dwarf stars.

“In the presence of 10,000-solar luminosity stars,” says Dimitri Veras, an astrophysicist at the UK’s University of Warwick who co-authored the research, “it’s a different—much more violent—ball game.”

While the study of white dwarf stars as planetary systems is a brand new field (researchers discovered the first evidence of a planet orbiting a white dwarf just last year), astronomers have been inferring the swan songs of asteroids diving into the petite but searing stars for quite some time. When a sunlike star dies, it swells, expels a lot of its material, and eventually collapses, cramming a sunlike mass into an Earthlike space. That creates a powerful gravitational field that drags the star’s heavier elements into its center, leaving a pristine atmosphere of hydrogen with some helium. “I think of [white dwarves] as a blank sheet of paper,” says Mark Hollands, an astronomer at Warwick University,

When dirty asteroids full of iron or other metals hit the star and fragment, they leave characteristic streaks noticeable in the white dwarf’s light—which astronomers have seen in between half and a quarter of the Milky Way’s dead stars. But what’s sending all those asteroids to their doom? Veras’s research provides some insight, revealing a system-wide catastrophe that may help create so many asteroids. “It’s a great next step,” says Hollands, who was not directly involved with the study. “It really gives us an improved sense of how we can have such a large population.”

The asteroids’ fates come down to the subtle way light interacts with the rocky bodies. When sunbeams warm an asteroid, that energy is later released as infrared radiation (think of how heat-vision goggles can spot warm humans), causing a recoil that’s miniscule but adds up over time. Because asteroids have funky shapes, they experience recoils in various directions as they later release the heat energy. When those recoils don’t balance, the asteroid starts to spin—a phenomenon known as the YORP effect for the surnames of the scientists who described it, Yarkovsky, O’Keefe, Radzievskii, and Paddack.

Astronomers have observed nearby asteroids YORPing in rather modest ways. After the sun goes super-saiyan, however, everything changes. All that additional light, Veras calculates, will spin any asteroids smaller than 6 miles wide so fast that they break apart. The weakest will start going to pieces when they reach one rotation ever two to three hours, Veras says. Getting them turning that fast from a standstill may take a million years, he estimates. But that’s the blink of an eye for a system that’s lived for billions of tranquil years.

After one fracture, the smaller, leftover pieces will turn even more easily, breaking again and again, faster and faster. In systems like ours, the final relics of many asteroids will be their constituent boulders and pebbles, and the devastation will reach past Pluto’s orbit. “[The asteroid] belt will likely experience ubiquitous YORP-induced destruction,” Veras says.

In previous work in 2014 Veras sketched out the basics of the phenomenon, but the recent research covers a variety of asteroid compositions. The space rocks range in consistency from loose piles of rubble, to firmly attached boulders, to solid chunks of iron, and only the most strongly stuck together appear to survive the end of the solar system. “What’s shown in this work,” Hollands says, is that “during the [red] giant phase, [an asteroid] doesn’t really have much say in what happens.”

The new research also notes that the YORPocalypse will produce many asteroid pairs, where one smaller fragment orbits a larger chunk—something of an orbital novelty. These twins won’t last long though, because further spinning will continue to break them down.

In addition to providing a glimpse into a violent episode of our solar system’s future, the work bolsters researchers’ ability to read the histories of distant white dwarf systems by looking at their atmospheres. As astronomers continue to watch these stars shred any asteroid that gets too close, a better appreciation of the YORP-era conditions the rocks either survived or succumbed to will allow researchers to understand their whole lifecycle, Veras says, birth to death.

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On November 6, 2017 two storms lashed the Caribbean simultaneously. Hurricane Irma, feeding on the energy of warm seas, unleashed 185 mile-per-hour winds on the inhabitants of St. Martin, Barbuda, and other islands. Meanwhile, a hundred million miles away, a second excess of energy snapped part of the sun’s twisted magnetic field, causing a solar flare that flung x-rays and ultraviolet light toward Earth. At the height of the terrestrial tempest, the solar storm knocked out local emergency channels for about eight hours.

But while meteorologists had known Irma’s path for some time, the intense solar flare—the most powerful of the decade—came largely as a surprise. Researchers understand pretty well how the Earth’s atmosphere interacts with its surface to make rain, wind, and snow, but figuring out exactly how our local star generates “space weather” remains a big challenge. “On Earth they have this huge network of weather monitoring stations,” says Dan Seaton, a solar researcher at the University of Colorado in Boulder. “But on the sun we have some photos, a few extrapolations, and then there’s a lot of guesswork.”

The still under-construction Daniel K. Inouye Solar Telescope (DKIST), which released its first images and movies of the sun’s roiling surface on Wednesday, represents one major effort to narrow that gap. Its 13-foot mirror—three times wider than any other solar telescope—can already spot features no other instrument can. In the near future, the $344 million facility, which sits on Haleakala volcano in Hawaii, will also gauge the twists and turns of the invisible but fierce force that drives space weather: magnetism.

DKIST will help researchers “understand how the magnetic fields behave,” says Gianna Cauzzi, an astronomer at the National Solar Observatory, which manages DKIST. That’s key, she says, for “understanding when certain configurations can go off and why. That will give you a hint [that] there might be something coming.” Knowing that radio channels are more likely to go down, operators could arrange other forms of communication or at least warn others they expect to go silent.

The sun may seem like an unvarying yellow orb from afar, but a zoomed in view reveals a seething mass of swirling currents and rising blobs—more boiling water balloon than shining bauble. Physicists more or less understand how the star’s fusion furnace heats bubbles and sends them up to spill open on the surface, as well as how the wispy atmosphere streams outward. But how does the first lead to the second? The next stage in solar physics, Seaton says, will be to sew these two, largely incompatible pictures together with other models describing the solar wind and the Earth’s magnetic field into one large quilted theory covering the whole system.

And that’s where DKIST comes in. It has the keen vision needed to snap images of the sun in detail previously hinted at only in computer simulations. With its first footage, which researchers have not yet processed for scientific use, the telescope captured a field of Texas-sized boils breaking on the surface. No one knew exactly what these bubbling cells would look like, but to the naked eye the theorists appear to have gotten them mostly right. “I was blown away at how similar they looked to what the models are predicting,” says Courtney Peck, a solar scientist at the University of Boulder, “so I think we’re making a big step forward.”

On top of its massive mirror, the instrument gets additional power from its unique design. All telescopes focus the light they collect into a point to resolve an image, and for DKIST that point actually lies outside of the mirror itself. This configuration keeps all of the supporting optical machinery (such as a formidable cooling apparatus) away from the mirror, where it could otherwise block and scatter incoming light. “We hope it will be revolutionary,” Cauzzi says.

The strategy seems to have paid off. While construction won’t officially end until the summer, Wednesday’s images have already hit the best possible resolution for this wavelength of red light—capturing features 18 miles across. “This is a major accomplishment, as it means that both the telescope and all of the optics downstream do work as expected,” Cauzzi says.

That sharp focus is key to solving the star’s enigmas. Model builders, who try to recreate the behavior of huge phenomena like solar flares in computer simulations, are hungry for the precise data that DKIST promises to deliver. Such predictions change drastically when they vary tiny, impossible-to-see features on the surface, which they currently have to guess at. Together with novel perspectives from an upcoming European spacecraft, Seaton expects that future solar models will benefit from “a lot fewer assumptions and a lot more reality.”

And Wednesday’s images are just the beginning. By the time it becomes fully operational next year, the telescope will feature a total of five instruments capable of collecting colors in both the visible and near infrared parts of the spectrum.

Crucially, those instruments will also be able to resolve the invisible magnetic field lines that thread through the sun’s various layers, because their magnetic influence orients and filters light in recognizable ways. Solar physicists are especially curious to turn DKIST toward the corona, an atmospheric layer 10,000 times dimmer (but paradoxically much, much hotter) than the star’s surface. Eruptions punch through the corona en route to Earth (where they can cause electrical blackouts days later), so the magnetic field there is a crucial and still misunderstood piece of the space weather puzzle. “This is something we don’t have,” Cauzzi says.

Weather of all kinds is inherently chaotic, and just as winter storm forecasts still struggle to get the snowfall right, space forecasters may never be able to predict the exact time and intensity of a communications-disrupting solar flare like the type that hit the Caribbean three years ago. Nevertheless, Seaton suggests that more unified solar theories will help researchers better recognize when the magnetic field is primed to explode, and that DKIST’s unique abilities will contribute to various solar physics advances.

“Any time we have looked at the sun in a novel way, we have been instantly surprised by what we saw,” he says. “And it’s those things nobody expected to see that are going to lead to breakthroughs in deep understanding of how the system actually works.”

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A European space probe will soon launch with the specific mission of doing exactly what every child learns never to do—stare directly at the sun.

The intensity of the sun’s light blinds most camera systems, whether they’re squishy eyes or rigid iPhones. But the newest solar satellite’s peepers aren’t most camera systems. Slated for launch in early February, the European Space Agency’s Solar Orbiter will tag team with NASA’s Parker Solar Probe to study the enigmatic solar winds and magnetic field of our nearest star. While it won’t get as scorchingly close as its partner in exploration, the Solar Orbiter will use its unique set of instruments to take unprecedented measurements of the star, including a much anticipated first glimpse of the sun’s poles—a perspective current solar observatories lack.

“[The spacecraft] do good work on their own, but when you put them together into this system observatory, they get so much more powerful,” said Nicky Fox, the director of NASA’s Heliophysics Science Division during a press conference on Monday. “We’re excited to welcome the Solar Orbiter into our fleet.”

After a few years of delays, the European Space Agency (ESA) has delivered its Solar Orbiter to Florida’s Kennedy Space Center, where NASA is preparing it for launch as soon as February 7. Once in space, it will begin preliminary data collection in May, coordinating measurements with NASA’s Parker Solar Probe as that craft makes its fifth close approach to the sun. The 1.5-billion-dollar Solar Orbiter then faces a year-long journey—swinging around the sun, Venus, and the Earth to get into position—before it begins full science operations in November of 2021.

While the orbiter has a different skillset than Parker and is headed for a different solar region, both probes represent complementary attempts to unravel the same central mystery: a churning star sits at the center of our solar system, flinging outward gusts of charged particles that mess with our communications systems, but simultaneously keep us safe from the dangerous galactic rays of interstellar space. Heliophysicists know that the sun’s ever-shifting magnetic field plays a role in pushing out those particles, but can’t yet forecast when those protective breezes will get whipped up into damaging gales.

The Solar Orbiter will study the sun with two sets of instruments. The first is a suite of four so-called “in-situ” devices stuck onto a 12-foot rod that will directly gauge the zephyrs around it as one might do with a moistened finger stuck in the air. With the exception of one novel tool that can detect traces of heavy metals in the proton- and electron-based solar wind, this suite largely duplicates the senses of Parker. That redundancy will come as a boon to researchers, who will soon be able to compare the solar wind (which streams out from the sun in every direction) at two points relatively close to the sun. That’s a far cry from the number of weather stations meteorologists use on Earth, but a big improvement over just one.

The second set of instruments will increasingly set the orbiter apart as the mission evolves over the next seven years. Unlike Parker, it packs six remote sensing instruments—telescopes that will spy on the sun’s surface in everything from x-rays to visible light.

After this new orbiter opens its eyes in 2021, it will eventually take the closest images ever of the star, from just 26 million miles away. That’s about a quarter the distance between the Earth and the Sun, and inside the orbit of Mercury. Parker has already made closer approaches, but it doesn’t carry cameras capable of staring directly at the blazing orb—it’s focused on sampling the inner winds instead. The Solar Orbiter’s sun-facing telescopes sit safely inside the spacecraft, hidden behind its heatshield. When the time comes, viewing ports will open just enough to let in the sunlight needed to take pictures.

With both sets of instruments, researchers hope the Solar Orbiter will help them trace the solar wind back to its roots on the surface of the sun. “[It will] ideally provide, for the first time, the first full observation of the solar wind, starting by identifying its sources on the sun and then measuring all its properties as it flows outside throughout the atmosphere of the sun and as it reaches and passes our spacecraft,” said Yannis Zouganelis, the ESA deputy project scientist for Solar Orbiter.

Over time, the orbiter will leverage further encounters with Venus to tip its own orbit out of the plane that Earth and the other planets inhabit around the Sun’s equator. Reaching an orbit tipped at 33 degrees—which would bring it as high as northern Africa or Dallas, Texas if it were making a similar pass around Earth—it will snap the first pictures of the sun’s northern and southern poles. Here, simulations predict that dark, gaping holes (visible in ultraviolet light) expel tremendous amounts of wind. Current images taken from orbit around the equator catch just the edges of these unseen realms, which some scientists suspect may foretell the intensity of solar activity years down the line.

The unique perspective will also help researchers get a full, three-dimensional picture of the magnetic field at the poles and elsewhere. Other observatories have been able to gauge the field strength and estimate which way it’s pointing, but trying to do so while stuck on Earth is kind of like estimating depth with one eye closed. “Our models of solar winds and coronal mass ejections, they overlap critically on getting the magnetic field correct back at the sun,” said Chris Cyr, former NASA project scientist for the mission. “We’ve been making a lot of assumptions so far and this will give us a chance to check on that.”

The solar wind mystery has stood for decades, but with Solar Orbiter and the Parker Solar Probe on the case, some answers may finally be on the horizon. “It’s kind of a golden age for solar physics,” Fox said. “We’ve had to wait a long time for the technology to be ready.”

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Long before anyone considered exploring space with thrusters, German astronomer Johannes Kepler—noticing that the sun appeared to blow back the tails of comets—dreamt about getting around on celestial winds. “Provide ships or sails adapted to the heavenly breezes,” he wrote to Galileo Galilei in 1608, “and there will be some who will brave even that void.”

Four centuries later, a crowd-funded spacecraft, the LightSail 2, has become the latest to do just that. While wind as we know it certainly doesn’t blow in space, the ship can directly harness something else: modest nudges from sunbeams that tweak its path as it orbits around the Earth. The Planetary Society, a private space exploration organization, spearheaded the development of the spacecraft to prove that the tiny force exerted when light hits the backside of its shiny sail suffices as a form of transportation—a technology that could someday open up new types of space missions and provide crucial insight into destructive solar storms.

After nearly half a year of experimentation, the LightSail 2 team has learned what it takes to pilot the ultimate solar-powered space vehicle. Although it orbits hundreds of miles above the International Space Station, the thinnest reaches of Earth’s atmosphere extend farther still, slowly dragging satellites down to their doom. While the craft hasn’t been able to beat such air resistance consistently enough to fly away from the Earth, improved maneuvering has noticeably slowed the vehicle’s sinking, and on occasion even reversed it.

“There have been a number of intervals where we’ve also been able to increase the energy of the orbits,” says Justin Mansell, a PhD candidate at Purdue University and co-author of a recently released paper describing the vehicle’s performance so far. “That’s justified our mission success.”

LightSail 2 is not humanity’s first success at sailing on sunbeams. That honor goes to IKAROS, a roughly 50-foot by 50-foot Japanese spacecraft weighing hundreds of pounds. In 2010, it caught a measurable push from the sunlight in interplanetary space on its way to Venus.

LightSail 1 eventually became the next solar sail to safely reach space in 2015. The test craft succeeded in its primary objective of spreading its sail, but with no way to control its orientation it soon floundered, fell back toward Earth, and burned up in the atmosphere.

The sequel, The Planetary Society hoped, would realize the hopes and dreams of the more than 50,000 donors who had contributed a collective $7 million dollars to fund the two prototypes. Hitching a ride with two dozen Department of Defense satellites on SpaceX’s Falcon Heavy last June, it entered an orbit more than 400 miles above the Earth—nearly twice as high as its predecessor. Between the thinner air and a proper control system, the team aimed to achieve true altitude-adjusting, solar sail-powered flight.

But learning to control the vehicle hasn’t been smooth sailing. Unfurled, the feather-weight sail (made from a material called Mylar) could cover a boxing ring, but all steering power originates from a loaf-of-bread-sized body stuck to the middle. At just 11 pounds, LightSail 2 boasts the best heft-to-size ratio and the quickest acceleration of any solar sail to date. But that superlative makes it cumbersome to control, and as any sailor knows, tight control is crucial to getting where you want to go. “There are aspects that are weirdly analogous to sailing a ship,” says Mansell, who became certified to sail terrestrial ships in 2018.

LightSail 2 sails fastest when moving away from the sun, as the star’s rays push the craft “downwind.” For that part of the orbit the team points it away from the sun for maximum light exposure (imagine the most perilous position to hold an umbrella in during a gust of wind). Later on in its hour-and-a-half long orbit, however, it slips into the Earth’s shadow—doldrums for a solar sailor. It then swings back around the other side, struggling “upwind” against the sunlight’s pressure. For this part of the orbit, the team aims to align the sail’s edge toward the sun to minimize pushback.

To steer, the craft has two systems. Its modest body holds a small “momentum wheel,” which, when spun, twists the craft in the opposite direction. LightSail 2 also features two electrified metal coils that generate magnetic fields. These coils can grab onto the Earth’s magnetic field, letting operators align the spacecraft. Figuring out how to steer most efficiently accounts for much of the solar sailing learning curve, Mansell says.

But after five months of practice and data collection, the solar mariners feel confident that the vessel’s sail is helping it stay aloft. During periods when the sailors take their hands off the controls, the vehicle falls an average of 113 feet closer to Earth due to drag from the thin air. While actively sailing, however, LightSail 2 tends to drop just 65 feet. On their best day of sailing the team managed to raise the orbit by 24 feet. With sparse satellite information from this band of space the team wasn’t originally sure what kind of performance to expect, Mansell says, so the spacecraft is also doubling as a probe of far-atmospheric thickness.

“Even though we’re sailing really well, there’s days when the atmosphere is a bit more dense than normal,” he says. “Other days when the atmosphere is a little bit thinner at that altitude, we have a better chance at raising the orbit.”

To raise the orbit regularly, team members estimate that LightSail 2 would need to start out at least 500 miles above the surface. In its current location about 400 miles in the air, the vehicle is fated to continue its downward spiral and eventually flame out in the atmosphere—perhaps this summer. Before then, however, the team has two more experiments to run. They first plan to test their ability to hold a steady course, keeping the craft pointed straight at the sun. And as LightSail 2 really starts to plummet, they’ll try controlling the speed of its fall by changing its orientation.

The Planetary Society has no current plans for a LightSail 3, Mansell says, but the future of solar sailing lies in deep space. Solar sails work best far from Earth, where no atmospheric traces can slow them down and where they aren’t constantly dipping into shadow. NASA plans to launch a light-driven craft as early as next year aboard the first test of its upcoming Space Launch System, and the LightSail 2 team has helped consult. The Near-Earth Asteroid Scout will, as its name suggests, fly on a solar sail to a nearby asteroid and scout it.

Later on, solar sails might also make new types of missions possible. Traditional spacecraft use thrusters for quick tweaks to their paths, but generally remain confined to the same elliptical orbits that planets follow, as Johannes Kepler once discovered. The sun’s gravity governs these celestial routes, but adding a constant push from sunlight enables so-called “non-Keplerian” orbits. One could, for example, indefinitely balance a solar sail spacecraft between the Earth and the sun at a point beyond the reach of a vehicle relying on thrusters. If equipped with sun monitoring instruments, such an outpost could provide warning for solar storms up to a dozen times earlier than current space-based solar observatories.

Mansell says he’s excited for the future of solar sailing, and grateful to have participated in the team helping it get off the ground. “It’s been an incredible opportunity to be part of a mission that means so much to so many people.”

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History would have us believe that the night sky is permanent and unchanging. After all, navigators have steered their ships using fixed stellar patterns for centuries, and our eyes still trace the same outlines of the same heroes and villains that star gazers have identified for millennia. But what if we just haven’t been watching closely enough? What if our night sky is changing?

A group of astronomers aims to shake that assumption of stability with the Vanishing and Appearing Sources during a Century of Observations (VASCO) Project, by comparing 70-year-old surveys with recent images of the night sky to see what might have gone missing. After years of painstaking work, they recently announced their first results in the Astronomical Journal: at least 100 pinpricks of light that appeared in mid-20th century skies may have gone dark today. The vanished light sources could represent short-lived flashes in the night or, possibly, the disappearance of a lasting heavenly body, if researchers can indeed confirm what they’re seeing. The study authors stress that while their preliminary findings almost certainly represent natural and well-understood events, they hope that future results will be relevant to astronomy and the search for extraterrestrial intelligence (SETI).

“VASCO is a project that is both a SETI project and a conventional astrophysics project,” says Beatriz Villarroel, a researcher at the Nordic Institute for Theoretical Physics and coauthor of the recent report. “Even if we do SETI and have SETI questions, we are also interested in publishing other results that we find along the way.”

As a student, Villarroel used to write short stories. One day, her creative musings sparked a tangible question: Had any object ever vanished from the night sky? Had anyone checked?

When stars die they tend to explode in a burst of glory that’s hard to miss—Chinese astronomers documented the first supernova more than 1,800 years ago. But a star or galaxy melting quietly into the night would demand more explanation, Villarroel reasoned. Such a find could indicate an unexpected way for stars to die, or perhaps an advanced civilization blocking their sun with solar panels. Either would mark an exciting discovery. “If we should look for aliens,” Villarroel says, “maybe we should actually look for something that would be truly absurd to find.”

After getting her doctorate, Villarroel set out to answer her question with VASCO. Collaborating with a team of about 20 astronomers and astrophysicists, she led an effort to compare a series of sky images taken by the US Naval Observatory (USNO) over a period of decades starting in 1949, with observations by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) between 2010 and 2014.

The group used software to analyze the 600 million light sources that should have appeared in both datasets and came up with about 150,000 candidates that appeared to have winked out. They cross-referenced those missing lights with images from other datasets to isolate the especially promising possibilities. Finally, they scrutinized the remaining 24,000 candidates, one by one, to see which represented real points of light as opposed to camera malfunctions or similar accidents. In the end, they found about 100 sources that truly appeared to have vanished. “We have done the best work to remove anything that resembles any artifacts,” Villarroel says.

If further observations confirm that the disappearances represent real astronomical events, they could fall into two categories. They most likely indicate brief flashes, captured by chance by the original USNO survey, that have long since faded to black, Villarroel says. Any number of garden variety phenomena could explain these flickers—red dwarf flares, variable stars that dimmed below Pan-STARRS’s sensitivity, or the afterglow of a gamma ray burst, to name a few.

Or, tantalizingly, Villarroel could be on the trail of what she set out to look for: an enduring light source turning off. SETI enthusiasts have long speculated about alien civilizations with the godlike engineering power required to catch all the light emitted from a star, shielding it from our view. Here too, however, natural explanations exist, such as a so-called “red supergiant” skipping the supernova and collapsing directly into a black hole. These explosion-less deaths are thought to be quite rare, however, so if they’re taking place by the dozen then that discovery would be a little harder to explain. While encouraged by the early results, Villarroel again insists that it’s far too early to start fantasizing about alien engineers. “You would have to exclude all-natural things, and then there might also be new natural phenomena that we don’t know about,” she says, which “can be more exciting.”

In addition to continuing to study the hundred or so locations that appear to be missing a light source, the VASCO astronomers next plan on implementing a citizen science project where anybody interested can help them search through the rest of the 150,000 candidates. Villarroel estimates that hundreds more disappearing sources remain to be discovered.

The upcoming Large Synoptic Survey Telescope, which will start scanning the sky once every few nights in late 2022, should speed the hunt for such “transient” objects, but for the VASCO researchers that data is too far off. “We don’t have the patience for waiting,” Villarroel says. We are too curious.

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The sky is full of stars, but only one sits within our reach. Even as close as it is, the sun poses plenty of mysteries that can’t be solved from Earth. Odd patterns in sunlight during solar eclipses suggest that the corona, the sun’s outermost bit of atmosphere, inexplicably burns hundreds of times hotter than its surface. And while researchers can catch whiffs of the solar wind—streams of charged particles emanating from the sun—here on Earth, a lot of valuable data washes away by the time it blows by us. Getting measurements from right up next to the sun is a better way to understand our giant, burning ball of gas.

That’s why NASA’s Parker Solar Probe has spent the last year swooping closer and closer to the sun. In its first two passes it encountered new features that may help explain both the corona’s extreme heat and the origins of the solar wind, researchers announced on Wednesday in a series of four publications in Nature. As humanity’s first close encounter with a stellar environment continues, further observations will help researchers better understand how solar weather affects Earth, as well as how all stars age and die.

“We needed to go right to the source,” said Nicola Fox, director of NASA’s Heliophysics Division in a press conference on Wednesday.

In November 2018 and April of this year, two of Parker’s orbits brought it closer to the sun than any spacecraft had been before. Diving toward the sun and looping around the back, the probe reached about 15 million miles from the star’s surface—roughly six times closer than the distance between the sun and the Earth. At the shortest parts of its dive, the probe matched the speed of the sun’s rotation, in effect hovering above its surface. “We just sit over it, and let that part of the sun kind of wash over us,” says Kelly Korreck, head of Science Operations for one of Parker’s instrument suites that measures the solar wind.

Up close, the sun’s magnetic field and solar wind are both much more intense compared to what researchers can measure here on Earth, giving Parker an alien environment to explore. Korreck likens the craft’s experiences in the strong magnetic field to those of a diver entering the sea. “It’s kind of like going underwater,” she says. “Things sound different. You get different physics effects.”

Two features in particular came as surprises. The first were what the researchers are calling “rogue waves” in the magnetic field, which Parker registered as spikes in intensity and reversals in direction lasting for seconds to minutes as they rolled over the spacecraft. Dubbed Alfvén waves after Hannes Alfvén, a Swedish plasma physicist who won the 1970 Nobel prize in physics for their description, the phenomenon had been observed from Earth but never with such strength.

By observing the movement of electrons, which outline features in the magnetic field, the researchers confirmed that these waves represented tsunamis roaring outward from the sun—Parker saw as many as 1,000 speed by during an 11-day period of nearest approach. Their unexpected energy lends preliminary support to the idea that they could play a role in the peculiar heating of the corona. “It’s spectacular stuff and I’m quite sure it’s telling us something fundamental,” said Stuart Bale, the principal investigator of the instrument suite responsible for measuring the magnetic field, in the press conference.

The next step, according to Korreck, will be to monitor the rogue waves during closer approaches as the solar cycle heats up and the sun gets more active. Then, researchers could calculate whether they really are forceful enough to power the whole corona. “It’s going to take years,” she says.

Another surprise came when Parker measured the speed and direction of the solar wind buffeting the spacecraft. Astrophysicists expected that at this distance, 35 to 50 solar radii away from sun, the wind would come streaming straight outwards. Instead, they found that it was blowing to the side at over 100,000 miles per hour—presumably as the sun’s rotation drags the jetstream along. Researchers knew the wind would blow sideways in the corona, which is locked in sync with the sun’s rotation. But the edge of the corona lies ahead of Parker, somewhere between 10 and 30 solar radii from the sun.

Figuring out what kind of magnetic friction might be pulling the solar wind askance will prove key to understanding the future of not only our sun but stars in general. A star’s spinning speed slows down over time because its magnetic field rubs against the outflowing solar wind, causing it to lose rotational energy. So a tighter connection between the sun and its magnetic field suggests that this “spin down” process may play out more quickly than expected.

Knowing that the solar wind blows off the sun at such a sharp angle will also improve our ability to forecast when powerful pockets of energy from solar flares and plasma eruptions will reach Earth, where they can damage satellites and cause power outages. Ignoring this sideways component of the wind would be like ignoring crosswinds in predicting where a hurricane is making landfall, said Justin Kasper, who collaborates with Korreck on the instruments measuring solar wind, in the press conference “It’s already pointing to a way to improve space weather forecasts.”

The new research contains a variety of other results, including hints of a long-theorized dust-free zone around the sun, and an array of magnetic field structures and solar breezes far too small to be seen from Earth, and the researchers stress that this data is just the beginning. Over the next six years Parker will use further encounters with Venus to hurl itself closer and closer to the sun, eventually penetrating the corona itself for a direct look at the sun’s most mysterious layer. Fortunately, solar physicists are used to being patient.

“We’ve waited for decades and decades to understand these mysteries, some of them have been around for hundreds of years,” Fox said. “We’ve waited for tech to mature so we could actually fly this daring mission and get these observations.”

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Asteroids and comets tend to be heavy, but ‘oumuamua—the first interstellar visitor spotted passing through our solar system—acted impossibly light.

Today, two years after the object receded from sight, researchers are still puzzling over ‘oumuamua’s inexplicable behavior. Too agile to be a rocky asteroid but too dry to be an icy comet, the interloper didn’t fit into either of the usual boxes. The reason, an emerging but controversial theory contends, is that ‘oumuamua could have had a porous consistency that made it so light, even sunbeams could push it around. Now, a new analysis concludes that such a fluffy structure might actually be plausible. While fragile, it might have had the strength to survive its journey without breaking apart.

“It’s not the kind of object that we’ve seen before in our solar system, says Eirik Flekkøy

a physicist at the University of Oslo and co-author of the work, which appeared Monday in Astrophysical Journal Letters. “It’s a completely new thing.”

By the time astronomers noticed ‘oumuamua in the fall of 2017, it was already speeding back out toward the stars. Astronomers pegged it as an odd, cigar-shaped asteroid, until they noticed it was retreating faster than it should have due to gravity alone—behavior unheard of among space rocks, which typically have no other way of gaining speed.

In our solar system, the objects that speed up thanks to something other than gravity are usually comets, dirty snowballs that soften when they swing in close to the sun and get a propulsive boost by spraying a shower of melting ice behind them. Yet ‘oumuamua showed no signs of such a cometary tail, even in a recent retroactive analysis of observations from when it should have been melting the most.

But if icy plumes weren’t driving ‘oumuamua’s speedy escape, what was? One provocative paper suggested that pressure from sunlight itself was pushing the object away, as light particles have billiard ball-like momentum. But considering ‘oumuamua’s assumed heft as an asteroid, it would need a giant flat surface to catch enough of the sun’s rays to get any kind of boost from the barrage of light particles. “There’s not really any plausible mechanism that could form such a thing, except production [by an alien civilization],” says Flekkøy. But if anyone was home they didn’t appear to be hailing us.

In February, however, Space Telescope Science Institute astronomer Amaya Moro-Martín proposed that the sun was pushing ‘oumuamua not because it was flying a massive sail, but because ‘oumuamua was a lightweight.

Neither ice nor rock, the object could be a fluffy conglomeration of dust and ice grains. The researchers refer to this structure as a “fractal aggregate” for its porous patterns that repeat across different size scales. Whether viewed by the naked eye, with a magnifying glass, or under a microscope, a fractal ‘oumuamua would feature holes of many sizes. “I think if you hit this thing it would be a little bit like hitting a spider web,” Flekkøy says.

Intrigued by Moro-Martín’s suggestion, Flekkøy and his colleagues set out to check whether the fractal aggregate hypothesis held up. They noticed that an observed slowing of ‘oumuamua’s rotation supported the theory, because the speed of the slowing fit with a phenomenon where light can push harder on some parts of a surface—such as shinier parts—than it pushes on others. When the object cools after being heated up by the sun, the departure of heat exerts gentle pushes too. All these uneven nudges can add up to make a lumpy object spin faster or slower over time. So if sunbeams could turn ‘oumuamua, the researchers reasoned, perhaps they could speed it up too.

The group also calculated how well the theoretical dust ball would hold together under the duress of spinning (think of how playground roundabouts fling people off) and the sun’s tendency to gravitationally tug harder on ‘oumuamua’s closer side than its farther side. “If this is such a filamentary, porous, fractal structure, would it survive,” Flekkøy says. “And the answer is fairly safely, yes.”

Yet the object’s extreme properties strain the credulity of other researchers. To visibly respond to sunlight over just months of observation, ‘oumuamua would need to be one hundred times less dense than air at sea level, making it even lighter than the lightest materials engineers can produce—substances known as aerogels. “These aerogels we create through very careful technology,” says Roman Rafikov, an astrophysicist at the University of Cambridge. “How do you reconstruct this in interstellar space?”

Models of the early solar system have particles bumping into each other and forming small fractal patterns naturally, but Rafikov questions whether these cosmic dust bunnies could really avoid disruption long enough to grow into ‘oumuamua-like objects. He admits, however, that he prefers the fractals theory to an aliens one, and that he can’t come up with a more likely scenario. “If I had an alternative,” Rafikov says, “I would have published it long ago.”

If dust fractals do get big and occasionally stray close enough to Earth for astronomers to spot them, those observations could tell researchers about the conditions and processes that lead to the formation of planets.

But ‘oumuamua itself has long since disappeared into the night, so astronomers can’t evaluate the dust cloud theory through direct observations. And while a second interstellar visitor is passing through the solar system at this very moment, it looks like a typical no-drama comet. Future passersby, Flekkøy and Rafikov both hope, will be members of the oddball ‘oumuamua family, whatever that family might be.

“In my career so far, ‘oumuamua was the most puzzling object,” Rafikov says. “If [similar objects] actually keep coming into our solar system, we might be better prepared for this kind of analysis.”

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A battle rages on the surface of the sun. Wavy spikes shoot up to thousands of miles high, while plasma bombs explode at the edges of sunspots. Now, solar researchers may have observed another weapon in our nearest star’s arsenal: Texas-sized balls of heat and light.

These spheres streak through the plasma between the sun’s surface and corona (atmosphere), according to a recent report in the Astrophysical Journal Letters. The heliophysicists who made the observation christened them “cannonballs” because they trace out arcs as they fly (and, presumably, because it sounds super cool). The unconfirmed phenomenon could help explain the ungodly temperatures found in the sun’s upper atmosphere, among other mysteries of plasma physics.

The action goes down in the sun’s chromosphere, which starts where the photosphere (the part that will blind you) ends, and extends to the corona (the wispy atmosphere visible during an eclipse). Exactly how this transition zone works remains unknown, however, with the temperature inexplicably rising from a cool 10,000 degrees F to a sizzling few million degrees over the course of just thousands of miles.

“It’s still a big problem why the temperature changes so fast,” says Xiaohong Li, a PhD student at China’s National Astronomical Observatories and co-author of the work. “This is the problem that all the [solar] physicists are trying to solve.”

Li and her collaborators got to know this enigmatic layer of plasma intimately by binging dozens of hours of footage taken by various high-resolution solar telescopes, focusing on a particular shade of scarlet light emitted by the chromosphere’s hydrogen. For six months, the team downloaded videos every day and scoured them for clues. “Anybody could have found it,” Li says. “People don’t spend so much time focusing on the small details.”

When Jun Zhang, a professor at the National Astronomical Observatories, spotted the first flying cannonball in footage from a solar telescope at the Fuxian Solar Observatory the spring of 2018, he suspected it was just a blip in the recording. After a month of searching through the telescope’s archives, however, he found a second example. Only after the team had amassed a handful of these events, he says, did he start to get excited. They eventually found 20 cannonballs, and estimate that perhaps 40 of the spheres sail through the chromosphere at any given time.

The blobs, which measure about 700 miles across and fly at about 125,000 miles per hour, represent an abundance of heat and energy. The researchers propose that the sun’s magnetic energy launches the cannonballs in a violent but poorly understood event known as reconnection. The roiling surface of the sun sends powerful magnetic fields arcing up into the chromosphere, and when two arcs oriented in different directions smash together they can abruptly snap, then link together in a new orientation. Higher in the atmosphere, more energetic versions of these explosions trigger solar flares and coronal mass ejections. When the team cross-referenced their video clips with high level magnetic field images from NASA’s Solar Dynamics Observatory, they found rough support for the theory that reconnection was powering their cannonballs, sending them along the arc of the magnetic field.

Other solar scientists, however, say that without detailed magnetic measurements, cannonballs may not merit their catchy moniker. Any feature too small to resolve clearly can appear spherical, and without real height data their rising and falling behavior remains speculative, according to Michiel van Noort, a heliosphere scientist at the Max Planck Institute for Solar Research. He wonders whether the features may not be actual blobs of physical material flung from the surface, but rather garden-variety waves rolling through the chromosphere’s plasma. Such plasma pulses wouldn’t require anything as exotic as reconnection to get going, he says.

Marco Velli, a solar physicist at UCLA and observatory scientist on NASA’s current Parker Solar Probe mission, has similar questions. The cannonballs’ speeds are close to those of plasma waves in the chromosphere, he says, and without more examples it’s hard to tell the two apart.

He finds the results intriguing, however, and hopes follow-up research—perhaps using artificial intelligence to conduct a wider survey of solar footage—will turn up more cases to study. If further scrutiny does prove that magnetic reconnection causes cannonballs, they would serve as an important window into how reconnection takes place in calm, comparatively low-energy environments. A better understanding of how reconnection shoots energy and material into the sun’s atmosphere would also help us figure out how much the phenomenon contributes to the corona’s heating.

Physicists need every insight into reconnection they can get, Velli stresses, and not only to understand the sun. Lacking a detailed understanding of reconnection is also the main showstopper when it comes to producing energy from nuclear fusion, where reactors need strong, stable, non-reconnecting magnetic fields to keep plasma under control. “[Reconnection] is a universal process,” he says. “It’s important.”

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Discovering a new star is always a delight in astronomy. So you can probably imagine the excitement over discovering a giant stream of stars winding through the Milky Way.

A new study published this month in the journal Astronomy and Astrophysics details new observations of a 1,300-light-year-long cluster of more than 4,000 stars that have been moving together through the southern sky for about a billion years now. Distributed like a river of bright lights, a cluster like this has never been found so close to Earth, and could create some useful opportunities for learning about the structure and evolution of the galaxy.

“Similar stream-like structures have been known for quite a while now,” says Stefan Meingast, a researcher from the University of Vienna and the lead author of the new study. They are typically considered remnants of more globular clusters or dwarf galaxies that have been pulled apart and distorted over time, but still share a pattern of movement that hint at a shared origin.

Previous streams have been found in the outskirts of the Milky Way. “Our stream, however, is the first one that was found inside the galaxy, in the immediate vicinity of the sun,” says Meingast. “It therefore is a unique probe for studying the evolution of clusters and for measuring the gravity field of the galaxy.”

There had been previous hints that such a stream existed, through some scattered observations. But this latest investigation is the first to confirm that this is a big, coherent structure. What changed? The European Space Agency’s Gaia mission. An audacious project launched in 2013, Gaia plans to catalog over 1 billion astronomical objects and provide the most precise 3D map of the galaxy ever made.

Yes, it’s a bit strange to think a cluster of stars this large was simply hiding in plain sight for so long, but astronomers know better than to feel embarrassed. When you think about how extraordinarily large space is, trying to locate even several thousand stars streaming through the galaxy is “truly like searching for the needle in the haystack,” says Meingast.

The team was initially tasked with simply using the Gaia data to locate groups of stars that were moving together, and eventually they came across the “structure” of these stars that were moving as a group. The team pinpointed only about 200 stars; the 4,000 figure, and their 1-billion-year age, are extrapolations based on an analysis of stellar brightness, distance, and other factors.

It’s an interesting discovery on its own, but there are some larger, more tantalizing implications worth unpacking. “In our interpretation,” says Meingast, “this phenomenon of stream-like systems is sort of a universal mechanism that must apply to all other star clusters as well.” There are probably many, many other stellar rivers coursing through the Milky Way, and the new findings give us a loose framework for how to find them.

That would suggest it’s actually incredibly common for stars in the Milky Way to have formed in young clusters which are later on stretched out by the gravitational field of the galaxy. Meingast poses the idea that the sun was probably formed in a cluster some 4 to 5 billion years ago. So that raises the question, where are its siblings? It’s possible they’re scattered all across the galaxy as they’ve been stretched out over time, and if that’s the case, there will definitely be an interest in tracking those stars down for a family reunion.

The team hopes to follow-up on the new findings with a more detailed look at the stream that can confirm the age and quantity of stars that are part of the river, as well as using the Gaia data to locate more streams in the galaxy. The study is yet another affirmation of the impact of the Gaia mission on the astronomy community, and it’s a good bet we’ll be hearing of many more discoveries like this moving forward. There’s also a possibility the structure can play a significant role in helping scientists better characterize the gravitational field of the galaxy, and act as a useful target for planet-hunting missions. All rivers lead somewhere, even in space.

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Gaze up at the sky one evening and you’re likely to see the crisp blue sky of the afternoon replaced with a reddish-orange hue stretching for miles. You might be wondering: Why does the color of the sky change at different times of the day? The answer has to do with how light from the Sun interacts with the atmosphere surrounding the Earth.

Light travels in waves. Every color we see is determined by the length of those waves. Red wavelengths are the longest, and as you go through the rainbow the waves get shorter and shorter until you reach the blues and violets, which are the smallest.

As the Sun’s light travels towards us, at first all it encounters is the emptiness of space. But here on Earth, swirling in the air around us are thousands of near-invisible particles. Dust and water droplets are the larger ones, but there are also the minuscule gas molecules—mostly oxygen and nitrogen—that make up the air itself. The wavelengths that make it to the Earth’s atmosphere collide with these particles, which sends light bouncing in many different directions. Think of it like this: If you’ve ever been in a crowded bumper-car pavilion at an amusement park, bumping into other cars and being bumped into yourself, you’ve played the part of a light wave.

But not all wavelengths bounce around to the same degree.

“The atmosphere acts as a filter, and it’s always happening, you just don’t necessarily know it. It’s basically an effect of selective scattering,” says Stephen Corfidi, a meteorologist at the National Oceanic and Atmospheric Administration.

Blue wavelengths, because of their smaller size, are scattered more easily and in many directions. Red wavelengths, which are larger, are scattered the least by those tiny particles in the air.

During the day, when the light has the shortest distance to travel through the atmosphere, what we end up seeing are the blue waves that have been scattered all across the sky. At the day’s end, though, the light has to travel through much more of the atmosphere, and those short, blue light waves have a tough time getting past all the molecules. They mostly get scattered away before they ever reach us. The result is that red sky we see at sunset, since longer red wavelengths are still able to penetrate the atmosphere.

So when you see a red sky at night, just remember that it’s actually the last remaining survivor of the whole rainbow of colors.

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There is no shortage of innovation in NASA’s mission roster. Whether you are landing on Mars or entering orbit around an alien planet, missions to space require mind-blowing technological advances. This year the most ingenious spacecraft accolade (and our award for Innovation of the Year) goes to NASA’s Parker Solar Probe. This spacecraft is going to the most deadly place in the solar system—our sun. And it’s not just getting kind of close: as NASA likes to say, it’s going to “kiss” our hellishly hot host star.

No space agency has ever sent a spacecraft so close to the sun before. Previous attempts have inched as near as 25 million miles from the surface, but Parker Solar Probe will orbit the sun at an average distance of only 4 million miles. In order to do this and not melt into a gooey pile of metal, it is equipped with a revolutionary heat shield. The surface of the sun averages around 10,000 degrees Fahrenheit, but Parker Solar Probe won’t get that close. The team expects the spacecraft to reach temperatures of around 2,500 degrees Fahrenheit at most during its 6.5-year mission, and it’s built to beat that heat without a problem.

The heat shield is made up of a carbon-carbon material, similar to what is found in some golf clubs, but this carbon has been heated up. The shield also features a special carbon foam that is made up of 97% air. With a nice coating of white paint on the front to deflect the sun’s rays, this spacecraft is all set to survive an otherwise deadly environment. And all of that protection is only 8 feet in diameter, 4.5 inches thick, and 160 pounds.

The mission designers had to wait decades for the technology to become available. After all, if you’re going this close to the sun and your heat shield isn’t up to the task, the rest of the spacecraft doesn’t stand a chance.

And it’s not just the mission or the thermal protection system that makes it worthy of PopSci’s highest Best of What’s New honor: Parker Solar Probe is also outfitted with some new autonomous software. Because the spacecraft has such a long journey—6.5 years to get into the right orbit—the team had to make sure that Parker could correct its position, or “attitude,” if it shifted a bit too much to either side. The heat shield’s protective design is all for naught if it isn’t pointed toward the sun, so engineers added sensors to detect heat in inappropriate spots and correct flight angles as needed.

Since launching on August 12, Parker Solar Probe has already passed the sun at a distance of only 15 million miles, beating all previous records. It also happened to be going 213,000 miles per hour at the time, making it the fastest spacecraft ever. It won’t give up the record anytime soon, either: when Parker lowers itself closer to the sun around 2025, it will be zooming around the star at a dizzying 430,000 miles per hour.

Understanding the sun’s weather and behavior is important because large solar events have a direct impact on Earth, as well as our satellites in orbit. This revolutionary mission sets out to solve some of the biggest mysteries we have about our giant fusion reactor in the sky. Parker is the clear standout of BOWN 2018: It’s a spacecraft that will be beating records—and changing entire fields of research—for years to come.

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Around 11 p.m. on Monday, NASA’s mission to “touch the sun” officially broke the record for fastest moving spacecraft—therefore becoming the fastest human-made object ever, relative to the sun. Registering just one historical moment wasn’t enough for the plucky explorer though, because on the same day the Parker Solar Probe also got closer to the sun than any other probe before it.

“It’s been just 78 days since Parker Solar Probe launched, and we’ve now come closer to our star than any other spacecraft in history,” said Project Manager Andy Driesman in a press release.

The new speed to beat is 153,454 miles per hour as viewed from a stationary sun, according to the team’s calculations. That’s more than 90 times faster than your typical bullet and more than twice as fast as the Earth orbits our host star, which is the fastest most of us will ever get to travel. That clip also works out to just over two ten-thousandths of the speed of light, or 230 “microlights,” as astrophysicist Jonathon McDowell put it on Twitter. As of Monday, that ferocious velocity had brought it 26.55 million miles away from the sun’s surface, or about three times closer to the star than Earth’s orbit.

It’s no coincidence that Parker broke the two records, both set by the German-built and American-launched Helios 2 probe in April 1976, on the same day. The vast majority of that motion came not from the spacecraft’s launch rocket or engines, but from the fact that it is plummeting toward the center of the solar system.

If we think of the direction things move under the force of gravity as “down,” then in a gravitational sense, the sun sits at the bottom of an upward-opening funnel—which the planets circle like one of those spiral coin wishing wells at the airport. The Earth “rolls” around this gravity well at 67,000 miles per hour (or 30 kilometers per second in the astrophysically preferred units). Anything faster will rise up out of the well, like probes such as Voyager and New Horizons did in order to reach the outer solar system. Anything slower will start to spiral in toward the sun like a quarter circling the drain.

McDowell of the Harvard-Smithsonian Center for Astrophysics likens Earth’s place in this gravitational well to the shallows at the beach. “We have to go a long distance to get out of the solar system, but we don’t have to get up very much,” he says. “Gravity is only lapping around our ankles.” New Horizons, which holds the record for launch speed from Earth, took off at 16 kilometers per second relative to our planet, but in the same direction as our orbital movement, boosting it by one Earth speed and pushing it out toward Pluto.

Parker took the opposite approach. Falling into the sun would be easy if the craft were stationary, but it started out cruising at Earth’s formidable velocity—so first, NASA’s rocket scientists had to slow it down. They fired it backward against Earth’s orbit, cutting its speed relative to the sun nearly in half and leaving it free to start falling inward. “That’s why the distance to the sun and the speed records are tied together,” McDowell says. “The closer you get, the deeper you are in the gravity well and the faster you’re falling.”

And fall it did. Now pushing 70 kilometers per second, the craft will continue to set new records continuously until its closest approach to the sun on November 6, when it will reach 95 kilometers per second (212,500 miles per hour) as it passes five times closer to the star than Earth ever does. From there it will come around the sun and start to climb back out of the gravity well, completing the first half of many orbits that will bring it closer and closer to the star’s surface.

Those loops will eventually plunge it directly into the poorly understood plasma that surrounds the sun. The corona paradoxically burns millions of degrees hotter than the surface of the star itself, despite extending millions of miles into space. NASA expects that Parker will directly sample this unexplored zone on its 22nd orbit, which will take place in about six years.

Until then it will continue to best its own speed and closest approach records, which McDowell says is a fitting update to the largely overlooked legacy of Helios 1 and 2. “The great 1970s space probes, the really ambitious ones, there were three pairs: Viking, Voyager, and Helios. You’ve heard of Viking and Voyager, but you’ve never heard of Helios,” McDowell says. Its measurements of the solar wind and magnetic field didn’t capture the public’s imagination in the same way as its camera-bearing cousins did, he suggests, but its speed record stood for nearly 42 years nonetheless.

Helios 1 still holds the record for fastest spacecraft moving with respect to Earth, at about 96 kilometers per second, but Parker is coming for that superlative too. It should beat that speed on November 5, according to McDowell, and set a new record of 110 kilometers per second two days later.

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Early Saturday morning in Florida, a bit after 3:30 a.m., a massive rocket carrying a 1,500 pound probe bound for the Sun stood ready on the launchpad. With four minutes left in the countdown, a few engineers called a ‘No go’—part of the system wasn’t 100 percent ready for launch. The countdown stopped. No one was taking any chances with this mission. Around an hour after the original launch time of 3:31 a.m., the launch was scrubbed.

Long before dawn on Sunday, the Delta IV Heavy rocket stood ready again. This is the second most powerful rocket in operation, bested only by SpaceX’s Falcon Heavy. This time, as the engineers ran through their last checklists, all systems were go—and the spacecraft was ready to sail toward the Sun.

Witnessing the launch of the Parker Solar Probe was its namesake, Eugene Parker. The mission is the only one in NASA history to be named after a researcher while they were still alive.

In 1958, Parker wrote a paper proposing the existence of the solar wind—plasma streaming outward from our host star. His theory wasn’t vindicated until NASA’s first planetary mission, Mariner 2.

Journey to a star

It will take seven years for the Parker Solar Probe to reach its ultimate destination, an orbit nearly 4 million miles from the Sun’s surface—exposed to its blistering heat, and closer than any other spacecraft has ever gotten. The probe is well-equipped for the scorching proximity, but getting [close enough to take detailed measurements of the outermost layer of the star takes careful planning.

During the seven-year voyage, the probe will slingshot around Venus seven times, losing much of the sideways momentum it started the trip with (remember, Earth is moving around the Sun at 67,000 miles per hour, so anything coming from our planet has to account for that as it heads out into space.) But while it slows its sideways momentum, it will start going faster along its own path, eventually accelerating to 430,000 miles per hour—faster than any spacecraft before—as it makes its closest approach to our nearest star.

Its first few weeks will start more slowly. Now that it’s safely launched and on its way, the spacecraft will start deploying its antenna and other instruments. It will cruise by Venus for the first time in October. By November it will reach within 15 million miles of the Sun, closer than any other spacecraft has ever gotten.

Just after the launch, Parker was interviewed on NASA live and asked how he was feeling about the launch. He replied: “All I can say is, wow, here we go! We’re in for some learning over the next few years.”

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Update 8-12-18: We have liftoff! A Delta IV Heavy rocket carrying the Parker Solar Probe blasted off at 3:31 a.m. EDT on Sunday, August 12.

Update 8-11-18: Issues were identified during the countdown to launch on Saturday morning, and the 65 minute launch window closed before they were resolved. They’ll attempt to launch again on Sunday around the same time. Original article continues below.

Just like beachgoers looking to get a tan, NASA has its own date with the sun this summer. If all goes well, at 3:33 a.m. on Saturday, August 11, the agency will launch the Parker Solar Probe on a seven-year journey to get closer to the sun than any other man-made object. The mission will see the car-size spacecraft rendezvous with the corona, the outermost layer of the sun’s atmosphere, located several million miles from the surface of the star.

After slingshotting around Venus, the probe itself will get within 3.8 million miles of the surface of the sun, dipping into the corona to perform a series of experiments aimed at studying three major solar mysteries: how the electric and magnetic fields in the corona impact solar wind, what causes energized particles to accelerate into space, and why the corona is hotter than the surface of the sun (by several million degrees Fahrenheit).

While scientists have long studied solar wind—the flow of charged plasma from the sun that not only creates the aurora when it hits the Earth’s magnetic field, but also disrupts communications systems—they don’t quite know how that material is accelerated to supersonic speeds reaching over one million miles per hour. It’s been theorized that this occurs in the corona, thus the Parker Solar Probe and its suite of instruments (more on that here) will be perfectly situated to observe the turbulent energy patterns upon its arrival at the sun.

The spacecraft will also look for huge specific events that occur in the corona to dramatically propel the energized material out into space. “We’re interested in how powerful shock waves driven outward from the sun by massive eruptions of solar material, known as coronal mass ejections, can accelerate charged particles to the extreme energies measured by spacecraft located near Earth’s orbit,” says Rob Decker, Parker Solar Probe deputy project scientist at the Johns Hopkins Applied Physics Lab. “As these shock waves pass over Parker Solar Probe, its instruments will measure the properties of the shock waves and of the charged particles in the early stages of the energization process.”

The Parker Solar Probe will also study the intense temperatures in the corona. The surface of the sun is a relatively cool 7,000 degrees Fahrenheit, while the plasma in the corona spikes up to several million degrees Fahrenheit—a bit of a puzzle, since the sun’s energy originates in its core, and we’d expect the heat to lessen as the distance from the core increases. “Since Parker Solar Probe will pass through this hot corona at a minimum distance of only nine solar radii [the solar radius is 432,300 miles] above the Sun’s surface, instruments on the spacecraft should detect remnant signatures of the prominent coronal plasma heating process,” says Decker.

Of course, as the probe must withstand these intense temperatures, new technology had to be developed to protect the sensitive instruments—a process that essentially took six decades. The mission’s roots can be traced back to 1958, when astrophysicist Eugene Parker, for whom the probe is named, published a paper theorizing the existence of solar winds, which had never been recorded or measured. (His theory was proven correct just two years later.) Since then, scientists longed to send a probe to study the sun. “The technology development took several decades to catch up with scientific aspirations,” says Decker. “The thermal protection system (TPS) and the actively cooled solar arrays designed and developed for and installed on Parker Solar Probe are key examples.”

Not only will the plethora of data that the Parker Solar Probe will send back to Earth excite sun researchers, but it will also have major implications for the future of human spaceflight. The energized particles that hit the Earth after intense solar activity create radiation hazards that detrimentally impact human bodies (say, astronauts aboard the ISS, or eventually astronauts on Mars), as well as sensitive electronic equipment on spacecraft. “The eventual goal is to predict when the explosive solar events (such as solar flares and coronal mass ejections) that produce these particles will occur,” says Decker. “Measurements from Parker Solar Probe should help us understand what subtle signatures of activity on the Sun are actually precursors of impending solar eruptions.” If we can predict such solar activity in advance, hopefully we’d be able to provide warnings to crewed missions—much in the same way radar and satellites help us track Earth’s weather systems.

While each orbit of the Parker Solar Probe brings the it closer to the sun, we have some time to wait for the results—the spacecraft won’t enter the corona until its 22nd orbit in 2024. It will, however, start sending back data on its first approach in November this year, hopefully leading to early discoveries. Till then, we’ll just have to keep our eyes on the launch.

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Many newborn and toddler stars are not all that different from newborn and toddler humans—prone to bouts of cranky energy, loud and violent tempers, and indiscriminately wailing and vomiting heaps of disgusting matter in every direction. It’s natural to assume even our 4.6 billion-year-old sun had a messy heyday in its youth, but without any hard evidence to prove this was case, the only thing many scientists had going for them were strong suspicions. New data, focused around a peculiar set of ancient blue crystals from space, seems to suggest the sun emitted a much higher flux of cosmic rays in its early history than we once thought.

Those blue crystals are called hibonite, and they’ve arrived here on Earth by way of meteorite impacts. Hibonite are effectively some of the first minerals formed in the solar system, created by the cooling gas derived from the sun. The new study, published in Nature Astronomy, focuses on the Murchison meteorite, which fell in Australia in 1969, likely originating from an asteroid in the asteroid belt—and which possesses pieces of micron barely larger than the width of human hair.

“We think hibonites like those in Murchison formed close to the young sun, because that is where temperatures were high enough to form such minerals,” says Levke Kööp, a cosmochemistry researcher at the University of Chicago and the lead author of the new study. “Hibonites from Murchison are famous for showing large isotope anomalies that tell us about the types of stars that contributed material to the molecular cloud that the sun formed from.” The team doesn’t have an exact date on the hibonite grains, but based on the age of refractory elements in the meteorite, it pegs the crystals to be a little over 4.5 billion years old.

If hibonite really was produced by an early active sun, the answer would be found in analyzing the crystals’ helium and neon isotopes. High energy particles being ejected by a volatile young sun would have hit calcium and aluminum deposits in the crystals and split these atoms into neon and helium, and been irrevocably trapped for billions of years.

The research team studied the hibonite crystals using a highly sensitive mass spectrometer at ETH Zurich in Switzerland, melting the grains of hibonite down with a laser while the spectrometer measured and confirmed the presence of helium and neon concentrations.

Beyond simply illustrating that the young sun went through a phase of high activity, the new results also show how some meteorite materials from the solar nebula are directly affected by young sun irradiation. The team also noticed helium and neon were absent from younger crystals, indicating that something changed later in the irradiation conditions created by the sun, and raising the question of what happened. This sort of insight might augur later into a better understanding of how the roles star evolution plays in the creation of elements and materials that later on assemble into planets and other celestial bodies.

“Over the last few decades, there has been a controversy whether meteorites contain evidence of an early active sun,” says Kööp. “In general, even for us, it was hard to know what to expect from this study. In the end, we were very excited to see such a clear irradiation signature in the hibonites.”

Andrew Davis, a study coauthor affiliated with the University of Chicago and the Field Museum of Natural History, points out the minuscule size of the hibonite grains limits how much the team could measure helium and neon traces, as well as an analysis of the absolute age of the hibonite itself. Moreover, the analyses also involve destruction of the grains. “We are working on a new instrument in my lab to study the isotopic compositions of more elements in the hibonite grains, to better understand how different sources of dust were mixed in the early solar nebula,” he says.

Still, the implications of these findings alone shouldn’t be understated. “I’ve been involved with this type research for a very long time. I’ve constantly been skeptical of claims from scientists that traces of the early sun have been found.”

“With this new study,” he says, “I’m happy to change my mind.”

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Our sun is a fairly average star in the Milky Way—not the brightest, not the biggest, and only 4.5 billion years old. It’s only unique in that its light and heat sustains all the life on the only inhabited planet we know of in the universe. Luckily for us, it didn’t burn out before we showed up a few hundred thousand years ago. But how could it have that much fuel? Why hasn’t it been snuffed out like a candle or a campfire? And when will it finally burn out?

This was a pressing question in the 19th century, says Catherine Pilachowski, an astronomy professor at Indiana University. At the time, humans only understood two ways the sun could be generating energy: Either it was creating heat and light through gravitational contractions—pulling itself in at the center and emitting energy (in the form of heat that we feel on Earth), therefore getting smaller over time—or it was literally on fire, like the chemical reaction we see on Earth when we light a match or start a campfire. Thinking that either method could have been the sun’s modus operandi, scientists at the time calculated exactly how long the sun could have existed using both methods. But neither result squared up with what we knew the age of the solar system to be—4.5 billion years. If the sun were contracting or burning, it would have run out of fuel long before we came around. Clearly, something else was going on.

A few decades later and armed with Einstein’s famous E = mc2, which confirmed anything that has mass must have an equivalent amount of energy, 1920s British astronomers proposed that the sun was actually converting its mass into energy. However, instead of a furnace that converts wood and coal into ash and blackened carbon (emitting light and heat along the way), the center of the sun is more like a gigantic nuclear power plant.

The sun contains a massive number of hydrogen atoms. Typically, a neutral hydrogen atom contains a positively charged proton and a negatively charged electron that orbits it. When this atom meets one of its fellow hydrogen atoms, their respective outer electrons magnetically repel each other like bodyguards. This prevents any of the protons from meeting each other. But the sun’s core is so hot and so pressurized that atoms whiz around with so much kinetic energy that they overcome the force binding them together and electrons separate from their protons. This means the protons, usually stuck inside the hydrogen atom’s nucleus, can actually touch, and they join together in a process called thermonuclear fusion.

Just like inside a nuclear reactor, atoms inside the sun’s core slam into each other every second. Most often, four hydrogen protons fuse together to create one helium atom. Along the way, a tiny bit of the mass in those four miniscule protons is “lost;” but since the universe conserves matter, it can’t just disappear. Rather, that mass gets converted into a dramatic amount of energy—every second, the sun radiates 3.9 x 10²⁶ watts of power. (This is such a huge amount of energy that there is honestly no Earth-centered analogy. Perhaps that number can be contextualized like this: This amount of watts is far more than all of the electricity the entire world would use, at current rates, over several hundred thousand centuries.)

The efficiency of thermonuclear fusion is a major reason the sun has kept radiating heat for so long—the energy released by turning just one kilogram of hydrogen into helium is the same as burning 20,000 metric tons of coal. Because the sun is so massive, and relatively young, scientists estimate it has only used about half of its energy-producing hydrogen.

Eventually, the sun’s core will convert all of its hydrogen inside to helium and the star will die. But don’t sweat it. That won’t happen for about another 5 billion years.

Have a science question you want answered? Email us at ask@popsci.com, tweet at us with #AskPopSci, or tell us on Facebook. And we’ll look into it.

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In pictures, solar tornadoes look like our own planet’s massive whirling twisters (hence the name). That’s except for the fact that they are many times the size of our planet and they contain super-hot plasma instead of wind and rain. But similar to the ones on Earth, they spring up from the Sun’s surface, and then quickly die down again.

The resemblance, scientists have found, stops there. In research discussed at the European Week of Astronomy and Space Science (EWASS) this week, astronomers took a closer look at data collected during these events and found that the ‘tornadoes’ weren’t massive, spinning, vertical funnels after all. Instead, the plasma followed horizontal magnetic lines coming out of the sun. The structures seem to be anchored somewhere on the surface (though scientists don’t yet know by what), and they stay fairly stationary during their brief existence.

“”Perhaps for once the reality is less complicated than what we see,” Brigitte Schmieder, a collaborator on the project said in a statement. “Solar tornadoes sound scary but in fact they normally have no noticeable consequences for us. However, when a tornado prominence erupts, it can cause what’s known as space weather, potentially damaging power, satellite and communication networks on Earth.”

This was a busy week for space news. Don’t worry, we’ve got you covered. Keep reading.

Life on Venus?

Could there be life in the dense clouds of Venus? That question has been nagging astrobiologists since 1967 when Carl Sagan and Harold Morowitz speculated that the chemical and physical ingredients to make life possible were hanging out in Venus’ clouds. Now, that’s resurfaced in a paper out this week in the journal Astrobiology.

In it, researchers bring up the idea again, with some new insights: Dark splotches that appear and disappear in the Martian atmosphere bear some striking resemblances to algae blooms here on Earth, including being made of the same sized particles and their ephemeral nature. And recent discoveries of extremophile microbes on this planet (creatures that thrive in extreme conditions) give astrobiologists hope that similarly harsh environs on Venus could yield extraterrestrial fruit. But to know more, researchers are going to have to take a closer look.

To do so, Aerospace company Northrop Grumman is developing VAMP, the Venus Atmospheric Maneuverable Platform, which researchers could use to explore the clouds of Venus, hunting for life. It’s still very much in its early stages, but is an intriguing possibility for researchers.

Buncha Black Holes

Researchers found a dozen black holes orbiting a supermassive black hole near the center of the galaxy, Sagittarius A*. That could indicate that there are tens of thousands more black holes in that immediate area, something that astrophysicists have long predicted, but haven’t found evidence for before now.

Black holes are hard to see because they’re ‘holes’ that even light can’t escape. Researchers can see them when gas from a nearby star gets sucked towards a black hole and releases x-rays, but depending on their size and location relative to Earth even those binaries can be difficult to see. But by focusing on the area near the center of the galaxy and looking for weaker x-ray emissions (caused by stars with low masses paired with black holes) they were able to identify 12.

Extrapolating from what they were able to observe and their existing knowledge of the center of our galaxy, the researchers estimate that there could be hundreds of star and black hole pairs like this and tens of thousands of isolated black holes hanging out in an area about 6 light years away in the center of the galaxy.

“Everything you’d ever want to learn about the way big black holes interact with little black holes, you can learn by studying this distribution,” astrophysicist and lead author of the study Chuck Hailey said. “The Milky Way is really the only galaxy we have where we can study how supermassive black holes interact with little ones because we simply can’t see their interactions in other galaxies. In a sense, this is the only laboratory we have to study this phenomenon.”

Prize-less Lunar Prize

The Google Lunar XPrize is dead. Long live the Lunar X Prize. Google’s sponsorship of the prize ended without any of the five finalists claiming a portion of the $30 million in award money that was up for grabs. Now, XPrize hopes to give the teams another shot, and is looking for another sponsor to do so.

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Send your name to the Sun

You’re probably not going to go to space any time soon. But your name could. NASA is continuing its long tradition of sending people’s names into the cosmos with the Parker Solar Probe, set to blast off towards our host star this July.

Your name could be part of a spacecraft traveling 430,000 miles per hour, grazing the Sun’s atmosphere where temperatures reach 2,500 degrees Fahrenheit. Inside the probe, instruments designed to take a closer look at the Sun’s corona will stay at a cool room-temperature.

All you have to do is fill out a form on NASA’s website, and they’ll add your name to a microchip that the Parker Solar Probe will carry towards the Sun. You have until April 27 to put yourself in the running.

Here’s some other space news from this week:

First fifty launches

SpaceX’s Falcon 9 launch on Tuesday was fairly routine, sending a communications satellite into geostationary orbit. But it just so happened to be the 50th time SpaceX has launched a Falcon 9 rocket. The first launch of the Falcon 9 took place back in 2010.

Complex dust

First glances are great. But in space, it pays to take a second look. In this case, researchers took a peek at HR 4796A, a star system astronomers already knew had a ring of dusty debris encircling it. But at 7 billion miles across, that dust ring is a pipsqueak compared to the 150-billion-mile-wide larger dust ring they spotted with Hubble. The outer ring was just described in a paper in The Astronomical Journal.

A news release published by NASA describes the outer ring of dust as resembling “a donut-shaped inner tube that got hit by a truck.” Yum.

The eight million year old star is still very young by the standards of the Universe, and researchers think it is in the early stages of planet formation.

Not a pizza

Nope, this is not a pizza—though that seems to be what a lot of people think of when they first see this picture (at least around the PopSci offices). It’s actually a picture of storms neatly arranged around one of Jupiter’s poles.

Thanks to the Juno spacecraft we’re starting to learn a lot more about the gas giant’s interior, and we’re finding it’s not like other planets—not even Saturn, its closest companion in the solar system (at least in terms of size).

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There’s something about the geometry of space that’s never quite made sense to me. I know that the axial tilt of the Earth is the reason we have seasons, but if a slight angle away from the sun can make me see my breath in winter, why does being three million miles closer not make me melt in a pool of my own sweat? Is it really not any hotter when we’re at our shortest distance from our star? And if it is, then why should the 23.5° tilt to our axis matter at all?

I have to re-Google these questions every year at the perihelion, the point at which we’re the closest to the sun. Despite December 21 being the shortest day of the year in the northern hemisphere, it’s not until early January that we reach perihelion, when Earth gets the most intense dose of solar rays it will receive all year. Averaged across the whole globe, we’re getting sunlight 7-percent stronger in January than we are in July.

But it turns out that our distance to the sun actually has very little to do with the temperature we experience. It has far more to do with the angle at which the light hits us.

Light coming in at 90° hits as directly as possible. At the peak of winter in the northern hemisphere, the sun’s rays are pointed right at the Tropic of Capricorn, which is 23.5° below the equator. That band is getting the most direct light. Everywhere else is getting hit at an angle, and that means that the same energy in each metaphorical ray is spread across a larger area, weakening the heating effects at any given point.

Let’s imagine a one-mile-wide beam of light (and forget that there’s a third dimension for a sec, just for simplicity’s sake). At 90°, that beam is putting all its energy into heating up a one-mile stretch. But at a 30° angle, that same light will be spread across two miles, thus halving the intensity at each point. You can visualize this even better with a small flashlight. Point the beam at a vertical piece of paper and you see a direct circle of light. Angle the paper and you get a more diffuse ellipse. This is almost exactly what’s happening with Earth, except that our planet is round and made mostly of rock.

Our proximity to the sun would matter more if it heated us via convection. Like a hot oven, convection relies on a medium like air to carry heat to the target. But space is a vacuum, and without a gas or liquid to carry convection heat, the sun has to use radiant heat. Electromagnetic waves carry energy that heats molecules of air and earth on their arrival, rather than being hot when they arrive and transferring that heat. It’s the same kind of heating that makes a bonfire so hot on your face but not on your back—the fire isn’t warming the air, it’s sending out energy waves that causes your skin to heat up. The sun is over 90 million miles away at any given time, so adding or subtracting 3 million clicks doesn’t make a difference in radiant heat that we can notice.

The more intense sunlight is, the more energy it’s carrying and the more radiant heat it contains, so it’s really the intensity of the beams that matter, not how close we are to the source. Less intense sunlight in the northern hemisphere during January, combined with fewer hours of heating each day, means a colder winter the farther north you go.

But all this brings us to another question: if the southern hemisphere gets more intense light during its summer, does that mean January is hotter down there than July is up here?

Surprisingly—after telling you specifically that light intensity is what matters—it’s hotter during northern hemisphere summers. Even though we get less heating potential from the sun, there’s more land mass up here. The south has far more water in its oceans, and since water can absorb a lot of heat without increasing in temperature very much (this is called high specific heat capacity), a place with lots of water will be cooler. Land heats up fairly quickly, so despite a lower light intensity, northern summers end up hotter.

There you have it. We’re now getting farther and farther away from the sun until we reach our most distant point—in the dead heat of July. That’s space geometry for you.

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PopSci has teamed up with the University of Missouri, St. Louis, and East Central College in Union Missouri to provide an exclusive view of the eclipse from the path of totality.

Here’s a breakdown:

• 12:45 p.m. EST — the live stream begins
• 12:48 p.m. EST — the partial eclipse begins
• 2:15 p.m. EST to 2:18 p.m. EST — the total eclipse
• 3:43 p.m. EST — the partial eclipse ends

Fun fact: the camera shooting the phenomenon is equipped with a #14 shade solar filter, which is the same kind used in eclipse glasses.

Happy watching!

You may also be interested in:

• Can’t find safe eclipse glasses? Make your own eclipse projector instead
• How to photograph the solar eclipse: The only guide you need

• How to make sure your eclipse glasses actually work

• Songs to sing your way through the 2017 eclipse

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According to Smith’s Illustrated Astronomy—publication date 1855—the effects of a total eclipse of the sun are as follows: “The heavens are shrouded in darkness, so that the stars and planets become visible; the animal tribes become agitated; and a general gloom over-spreads the landscape.”

That gloom is the feeling of insignificance. Because in the darkness, you have to acknowledge you live on a planet orbiting a sun. And that sun is one star of billions, among the billions of galaxies in our universe. That gloom is awe.

That awe, to be precise, is the when the Moon perfectly blocks out the sun, casting its shadow on Earth, and leaving only the wispy, ephemeral aura of the Sun’s corona ghosting into the darkness. It happens only because of math and coincidence. A total solar eclipse is both chance and certainty.

Take this for example: If the radius of the Sun is 695,700 km, how can the moon—radius 1,737 km—block it out? It’s not an optical illusion. By chance, two cosmic numbers add up.

Here’s the first one: The radius of the Sun is about 400 times larger than that of the Moon. And the second? The Sun is about 400 times further away from the Earth than the Moon.

So if you’re an Earthling looking to the celestial heavens, the Sun and the moon usually appear the same size in the sky. If you were a Martian, though, your moons would appear much smaller than the Sun, and you’d never be lucky enough to see a total solar eclipse. The fact that we can experience one on Earth is a matter of distance and size being coincidentally relative chance.

What’s certain is the Moon and the Earth’s orbit around the Sun. When those heavenly bodies align—Earth, Moon, Sun (in that order)—you get a solar eclipse.

Think of the Earthling looking to the celestial heavens. Recall that the Sun and the Moon usually appear the same size in the sky. Usually. The moon’s path around Earth is an ellipse, not a perfect circle, which means the distance between us and the Moon changes all the time. When the Moon is farther away, it looks smaller from our earthly vantage point. So it blocks most, but not all of the Sun. We call that an annular eclipse. “Annular” because it leaves a fiery ring—or “annulus”—around the Moon. In a total eclipse, the Moon is nearer to Earth in its orbital path, and completely covers the Sun in the sky. Chance and certainty are at play again.

The Moon’s plane of orbit isn’t aligned with Earth’s. It’s tilted 5.1 degrees. So when the Moon falls in-between the Sun and Earth—which happens once every 29.5-day lunar cycle—the sun is obscured. But, rarely does the Moon’s shadow actually fall on Earth. Instead, it is usually lost in space.

In the end, the moon’s shadowy echo only appears on Earth when the moon’s tilted orbit meets the sun-Earth plane at two celestial points called nodes. It happens about twice a year. But it won’t happen forever. Every year, the Moon moves about 3.8 cm away from us. Six hundred million years from now, Earthlings will see their final total solar eclipse.

For more, check out the video, above. You can also subscribe to Popular Science on Youtube.

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A syzygy feels magical, and not just because it gets you at least 25 points in Scrabble. The whole concept of celestial bodies aligning feels poetic. When it results in a total solar eclipse here on Earth, you can feel for a few moments as though you’re part of something much greater and grander than yourself. The transience only makes it more beautiful. Which is why thousands of people will flock to the path of totality on August 21, 2017: to witness a once-in-a-lifetime phenomenon.

And it will happen all over again 22 months later. Minus the traffic.

That eclipse will happen mostly over the Pacific Ocean, though it will cross over southern Argentina and Chile towards the tail end. Total eclipses of the sun feel so rare because it takes so long for them to occur in the same place again. Hundreds of years pass between those recurrences, and if you’re not willing to travel around the globe to witness another, you’re likely to only see one in your lifetime. If you wanted to chase them, though, you could see an eclipse about every 18 months.

And that’s just total eclipses. Between partials and annulars, there are usually two or three solar eclipses every year. A partial eclipse is, as the name implies, when only part of the Moon covers the Sun. An annular eclipse is exactly like a total eclipse, except that the Moon isn’t close enough to Earth for the relative size to fully block the Sun’s rays.

So why do solar eclipses happen anyway?

It’s only when the Moon is close and directly aligned with the Sun that we experience a total darkening like the one Americans will witness this August. And to understand why that happens periodically, you first have to understand how the Moon goes around the Earth.

Bear with me, here. I know you think you already understand that, but let’s start with a quick question: Given that a new moon (the opposite of a full moon) occurs whenever the Moon is between the Earth and the Sun, why do we not have an eclipse every month? If you already know the answer, congratulations! You’re an astronomy buff—don’t rub it in. For the rest of the population, here goes.

The Moon goes around the Earth once every 28 days. During that time, it goes from full to new and back to full again. Here’s a pretty good graphic that shows you what the Moon looks like at each stage:

The only part of the Moon that you see from Earth is the bit illuminated by the Sun because it doesn’t produce its own light, it just reflects solar rays. When it’s gone a quarter of the way around, you see the half of the Big Cheese that faces the bright, shiny ball of flaming gas and plasma. And the same thing happens when it’s gone three quarters. The full moon occurs when the whole face can reflect the Sun’s light, or when the Moon is “behind” the Earth.

That might seem a little weird to you. If the Earth is between the Moon and the Sun, shouldn’t the Earth be casting a shadow onto the Moon, thereby preventing us from seeing it?

We call this phenomenon a lunar eclipse, and they don’t happen every month either. (And you can actually still see the Moon, it just looks blood red because the Earth’s atmosphere has scattered every other wavelength of light). The reason they don’t happen monthly is simple: All three celestial bodies would need to lie in the same plane for that to happen, and as it turns out, they don’t.

Here’s a picture of what eclipses look like to help you out:

Everything is lined up in a perfect syzygy. This doesn’t happen in most lunar cycles because the Moon isn’t traveling in a nice, even plane with the Sun. It orbits at an angle, such that most of the time it’s a few degrees off (on average, about five).

The Moon is actually casting a shadow at these times, it’s just that the shadow misses our planet. Partial eclipses happen when we just miss perfect alignment.

So in a way, it is kind of magical when everything lines up at just the right time and at just the right angles to produce a total solar eclipse. It’s just that the Moon is circling the Earth so frequently that you end up with those conditions every year and a half on average.

We won’t always have total solar eclipses

The Moon is drifting away from us. It’s not anything we said or did, it’s just how things are. See, every time the Moon pulls the oceans up into tides, our own planet’s rotation slows a tiny bit and the Moon’s orbit increases. This has to do with a transfer of angular momentum between the two bodies, and means that the Moon is getting farther away from Earth by a little more than two centimeters a year.

By some estimates, that means that in about 1.4 billion years the Moon will be far enough away that it won’t be able to totally block out the Sun’s light. So at some point, there will be One Final Eclipse, if only humans can survive long enough to see it. Just imagine the traffic.

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To watch the solar eclipse on August 21, you could invest in a pair of eclipse glasses. But high demand means high prices—and some of the only reputable retailers are sold out entirely. For a cheaper option, build a pinhole camera, which projects a harmless (but still delightful) image of the sun onto a blank surface.

Making a pinhole camera can be as simple as punching a hole in a piece of paper: The sun projects through the gap to throw an image onto another surface (like a second sheet of paper). By adjusting the position of the pinhole, you can focus the image, although you can’t exactly get an HD picture. Turning a cardboard box that fits over your head into a pinhole projector will reduce light interference and give you a better closeup, but that’s not an experience you can share with your friends.

A pair of binoculars, however, can project and magnify an image all at once, making it the perfect choice for your eclipse-watching party. Here’s how:

Tools and materials

• Pencil
• Binoculars
• Two pieces of cardboard
• Box cutter
• Tripod
• Duct tape
• Epoxy and a 1/4-inch 20 T-nut (optional)
• Aluminum foil

Instructions

1. With a pencil, trace the outline of the binocular’s magnifying lenses (the lenses you point at a target) onto the center of one piece of cardboard. Cut out these circles and discard them. You should now be able to poke the binoculars through the middle of the cardboard.
2. Attach the binoculars to the tripod. You can either tape them in place, or screw them onto the tripod’s plate. For the latter option, you’ll need a pair of binoculars with a tripod attachment, or you’ll first have to epoxy a 1/4-inch 20 T-nut onto the binoculars.
3. Place the tripod into a position where you can point it at the sun.
4. Fit the cut cardboard over the binoculars so it casts a shadow. The light that filters through the binoculars should now project two bright dots onto the ground. Cover one of the lenses with duct tape or aluminum foil, leaving only one dot. Use duct tape to seal up any space between the outer edge of the uncovered lens and the cardboard.
5. Place the second piece of cardboard so that the projected dot from the binoculars lands on it. Adjust the focus of the binoculars, and the relative positions of the cardboard and the tripod, until the dot is sharp and clear. This is the projected image of the sun. Just don’t leave the binoculars pointing at the cardboard for more than a few minutes—focused light can set the paper on fire!
6. As the moon passes over the sun, watch the eclipse happen in the projection (instead of staring directly up and risking your eyeballs). Happy viewing!

For more, check out the video, above. You can also subscribe to Popular Science on Youtube.

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This summer, for the first time since 1918, a total solar eclipse will cut a path across the mainland United States. On August 21, everyone in North America will be able to watch the moon pass in front of the sun, blotting out some or all of its light (depending on where you live). People near Lincoln City, Oregon will see the total eclipse around 9:05am PDT. Then the path of totality slants eastward, finishing up in South Carolina at 2:43pm EDT.

But hold on—if the moon rises in the east and sets in the west (or pretty close to it, anyway), why does the shadow of an eclipse move from west to east? The answer, says Angela Speck, an astronomer at the University of Missouri, is a matter of perspective.

Watching the sky from the ground, we can see the moon (and the sun and stars) cross from east to west, as if they were moving in a clockwise direction around us.

“It’s almost like we are geocentric,” says Speck, referring to the outdated idea that the sun and moon revolve around our own pale blue dot. “We think of the Earth as being stationary, and everything’s moving around us, but it’s not like that.”

So let’s take a step back and picture the motions of Earth and the moon from a different point-of-view than the one we’re used to.

The moon “rises” in the east because Earth spins counterclockwise. From the top down, that looks like this:

In the diagram above, “A” will see the moon on its horizon sooner than “B” will, just because of the way the Earth spins. Looking at that again from a side view, you can see that A is east of B:

So that’s why the moon, sun, and stars rise in the east. But let’s not forget that the moon is moving, too. It circles Earth in a counterclockwise direction, like this:

Look at A and B from the side again, and you’ll see that the Moon actually passes in front of B, in the west, first. That’s why the eclipse’s shadow will travel from west to east.

Earth spins at about 1,040 miles per hour, while the moon moves around the Earth at about 2,100 mph. That means the shadow of the eclipse will travel east at a speed of 2,100-1,040= 1,060 miles per hour.

If the moon is moving twice as fast as the Earth spins, why doesn’t it ever lap us and rise in the west instead? That’s because the moon has to travel in a circle that’s much larger than the Earth’s circumference—it takes 27 days for the moon to complete its orbit around the globe. Partly it takes so long because the Earth is spinning, too. This animation (from 0:04 to 0:14) helps to explain things:

For more perspectives on the upcoming eclipse, stay tuned for more coverage from PopSci.com, coming soon.

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Sunlike stars often come in twos and threes, and astronomers and astrophysicists have long wondered why. Are these pairs and trios born as multiple stars orbiting the same point, or do they meet up when the gravity of one star captures another?

A new analysis out of Harvard and UC-Berkeley suggests that, in fact, nearly all stars are likely born with a twin—including our own sun. The findings, recently accepted for publication in the Monthly Notices of the Royal Astronomical Society, are based on observations of newborn stars in a large cloud in the constellation Perseus.

Stars are born inside egg-shaped clouds called dense cores. These dusty gas clouds block the light from the stars inside and behind them. But fortunately for us, radio waves can penetrate through the darkness. The Very Large Array recently used radio waves to map all the young stars in the Perseus nursery, and the researchers drew on this data to understand the relationships between stars of different ages.

They found that binary stars separated by distances of 500 AU or more—that’s 500 times the distance between Earth and the sun—were extremely young stars less than 500,000 years old. In these systems, the two stars tended to be aligned with the long axis of the egg-shaped cloud.

Slightly older stars, between 500,000 and a million years old, tended to be closer together—separated by about 200 AU—and had no particular alignment within the cloud.

The study authors came up with a variety of mathematical models to explain the stars’ distribution, and concluded that the only way it makes sense is if all stars with sunlike masses start off with distant twins. Over the course of a million years or so, about 60 percent of the pairs split up (the authors think) and the rest ease in closer to one another.

The results support computer simulations that previously suggested stars form in twos, as well as observations that younger stars are more likely than older stars to form binary pairs. But the authors caution that the findings need to be checked in other star-forming clouds, and that more work needs to be done to understand the physics of this phenomenon.

If the results can be replicated, they’ll provide new evidence that the sun formed with a (non-identical) twin located 17 times farther away than Neptune. And it might have been an evil twin to boot. Scientists call this long-hypothesized twin “Nemesis“, because they suspect it booted the asteroid that killed the dinosaurs into Earth’s orbit.

“We are saying, yes, there probably was a Nemesis, a long time ago,” co-author Steven Stahler of UC Berkeley said in a statement.

But Nemesis has never been found. If it ever existed, it must have escaped from the gravitational pull of our sun and run off into the Milky Way, never to be seen again. So much for family.

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The spacecraft formerly known as the Solar Probe Plus shall henceforth be called the Parker Solar Probe—a nod to Eugene Parker, the first astrophysicist to describe solar wind. NASA announced the name change on Wednesday.

The mission itself isn’t news. NASA’s solar probe is launching in the summer of 2018, and if you know anything about how space exploration works, you know that means it’s been in the works for quite some time. If this is your first time hearing about it, you can check out PopSci’s recent coverage of the mission plan here. The highlights: the probe will travel for almost seven years, zipping along at record-breaking speeds to enter the sun’s corona, or atmosphere, and poke around with a suite of cutting-edge instruments.

The sun’s corona ejects highly-energized plasmas that make up solar wind, and studying the star up close could help us get better at predicting space weather—and better at protecting ourselves from potential damages that might result on Earth.

“This is the first time NASA has named a spacecraft for a living individual,” Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington, said in a statement. “It’s a testament to the importance of his body of work, founding a new field of science that also inspired my own research and many important science questions NASA continues to study and further understand every day. I’m very excited to be personally involved honoring a great man and his unprecedented legacy.”

Parker is set to launch in 2018, sometime during a 20-day window that starts on July 31.

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Humans foolish enough to gaze directly at the sun will likely perceive a uniformly-colored orb. But this miasma of incandescent plasma isn’t actually all that pristine: the star’s surface is usually peppered with dark spots created by magnetic activity.

Lines of the sun’s magnetic field pop out of its surface in bundles called pores, and when pores get too close to one another they squeeze the plasma between them to form relatively cool spots—3,800 degrees Kelvin in contrast to the rest of the surface’s 5,800 K or so temperature. Intense bursts of radiation called solar flares pop out of these plasma squeezes, and that radiation can wreak havoc on various electrical systems on Earth.

Sunspots have been monitored daily since 1849, and all that data has shown that their frequency waxes and wanes in an 11-year cycle. Other kinds of solar activity can still impact Earth while sunspots are sparse, but they serve as a decent index for the overall intensity of space weather.

As you can see from the image above, which was taken by NASA’s Solar Dynamics Observatory (SDO), our sun is looking pretty smooth these days. According to NASA, SDO returned spotless images of the star for 15 days straight starting on March 7, which marks the longest stretch of spotlessness since 2010.

The image on the left shows sunspot activity from the sun’s last “solar maximum”—an extreme period at one end of the solar cycle spectrum. The peak activity of the sun’s last cycle occurred in the spring of 2014. We’re not at the solar minimum yet, in all likelihood—based on the 11-year cycle schedule, we can expect that to happen sometime during 2019 or 2020. But NASA scientists say that the recent fortnight of sunny-side-up sun indicates that solar activity is winding down towards this low period just as we’d expect.

And the sun acting normal is a very good thing. Between 1645 and 1715 the sun eschewed its usual patterns of activity, casting the 11-year cycle aside in favor of a long stretch of minimal sunspots. This corresponded with a “little ice age” categorized by bitter winters. And you thought the polar vortex was a pain.

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Our sun might not seem as enigmatic as more exotic, distant stars, but it’s still a marvelously mysterious miasma of incandescent plasma. And it’s certainly worthy of our scientific attention: Curiosity aside, a violent solar event could disrupt satellites and cause $2 trillion in damages for the U.S. alone. Yet, despite living in its atmosphere, we don’t understand some of its defining phenomena. For sixty years, we haven’t understood why the surface is a cozy 5,500 Celsius, while the halo called the corona—several million kilometers away from the star’s surface and 12 orders of magnitude less dense—boasts a positively sizzling 1-2 million Celsius.

To figure out why, NASA needs to fly a little closer to the sun—and touch it.

We know that magnetic reconnection—when magnetic field lines moving in opposite directions intertwine and snap like rubber bands—propels nuclear weapon-like waves of energy away from surface. Meanwhile, magnetohydrodynamic waves—vibrating guitar string-like waves of magnetic force driven by the flow of plasma—transfer energy from the surface into corona. However, without more data, our understanding of phenomena like coronal heating and solar wind acceleration remain largely theoretical…but not for long.

Launching in 2018, NASA’s Solar Probe Plus will travel nearly seven years, setting a new record for fastest moving object as it zips 37.6 million kilometers closer to the sun than any spacecraft that has ever studied our host star. But what manner of sensory equipment does one bring to Dante’s Inferno?

Spacecraft systems engineer Mary Kae Lockwood tells PopSci that the craft will rely on four main instruments. The Solar Wind Electrons Alphas and Protons systems, or SWEAP, will monitor charges created by colliding electrons, protons and helium ions to analyze solar wind—ninety times closer to the sun than previous attempts. Similarly, the ISIS (Integrated Science Investigation of the Sun) employs a state-of-the-art detection system to analyze energetic particles (think: cancer-causing, satellite-disabling particles).

The FIELDS sensor, meanwhile, will analyze electric and magnetic fields, radio emissions, and shock waves—while gathering information on the high-speed dust particles sanding away at the craft using a technique discovered by accident. Lastly, the Wide-field Imager for Solar Probe, or WISPR telescope, will make 3D, cat-scan-like images of solar wind and the sun’s atmosphere.

There’s just one problem. Between intense heat, solar radiation, high-energy particles, the fallout of solar storms, dust, and limited communication opportunities at closest approach, all that sensitive equipment is going to an environment that almost makes Juno’s new home look sympathetic by comparison.

“One of the things we had to watch out for in the design,” according to Lockwood, was the electrical “charging” of the spacecraft by the solar wind. The probe has to be conductive “so that the instruments that are actually measuring the solar wind don’t have interference.”

To get close enough to worry about that, though, the probe’s has to “lose some energy” says Lockwood, performing several Venus flybys to shrink its orbit “[allowing] us to get . . . closer and closer to the sun.”

However, that comes with “interesting design challenges, because you’re not only going into the sun” as heatshield mechanical engineer Beth Congdon tells PopSci. “You get hot on approach, and then come out and get cold,” over and over for 7 flybys and 24 orbits. “You actually need to have it cyclically survive hot and cold temperatures.” And high energy particles. And hypervelocity dust. For that, you need a heat shield “different from any other heat shield that has ever existed.”

The incandescent elephant in the room

“A lot of heat shields you typically think about, like the shuttle . . . They have a few minutes maximum of that kind of heat.” But at the probe’s closest approach of 5.9 million kilometers, Congdon says, temperatures will reach up to 1,377 Celsius for a full day.

But carbon can come to the rescue. “On Earth, carbon likes to oxidise and make barbeque,” chimes Congdon, “[but] in the vacuum of space, it’s a great material for high temperature applications. The probe’s shield is made of carbon foam, sandwiched between layers of carbon composite, with a reflective ceramic coating.

What’s more, she says, most shields have the luxury of being attached to a vibration-dampening platform. This shield, on the other hand, had to be integrated in such a way that it could mitigate vibration without one “so that we could keep the whole system as low mass as possible.” The slim, trim, and ultralight build, however, makes it challenging to keep all the sensitive equipment hidden safely behind it.

To that end, the craft is outfitted with solar limb sensors. These sensors would be the first thing to get illuminated if the spacecraft started drifting off-kilter, and would inform the autonomous guidance and control system that keeps all the instruments behind the thermal protection system, and which is even outfitted with a backup processor in case of any malfunctions.

Meanwhile, the solar array, facing solar intensity 475 times greater than here on Earth—in an environment where “one degree of change, at closest approach, equals a 30 percent change in power”—will automatically retract behind the heat shield whenever it swings toward the sun. From there, it’ll be kept at a cool 160 Celsius by a network of water-filled titanium channels.

So while the heatshield weathers a minefield of million-mile-per-hour winds and countless coronal mass ejections, the communication system scarcely able to relay information for 11 straight days, the array will be kept comfortable—all while powering an autonomous 1,345 lb scientist on the doorstep of our little cosmic neighborhood’s big, confounding catalyst.

“Going to a place changes everything we think about a place. Just look at New Horizons and how it’s changed our thoughts, beliefs, and understanding of Pluto. We’re really excited to go and totally change our view of the sun,” says Congdon. Understanding the sun’s defining phenomena is a tantalizing goal. But first we have to contend with 143.3 million kilometers of space—and one of NASA’s most technically challenging builds, over half a century in the making.

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Forecasting the path of a storm is hard enough. But forecasting the path of a storm headed towards Earth from a distance of 92.6 million miles? That’s a Herculean task.

Luckily, there is now a forecasting model that is up to the challenge. Starting on October 1, space weather forecasters at NOAA’s Space Weather Prediction Center will be able to give a regional space weather forecast to utility companies, allowing them to brace for fluctuations in the energy grid.

The regions being forecasted are large for a local weather forecast, but compared to previous space weather models, the plots are relatively tiny–just 350 square miles, or about a third the size of Rhode Island. The model, which was developed by researchers at University of Michigan and Rice University, can give utilities up to 45 minutes of warning of severe solar activity, less if the solar storm is moving particularly quickly.

Solar storms, also known as geomagnetic disturbances can come in many forms, but some of the largest are coronal mass ejections (CMEs), or huge masses of plasma mixed together with magnetic fields that explode off of the sun periodically. Currently, astronomers can see a CME coming off the sun, and existing models can predict if it will hit Earth hours or even days ahead of time, but not with any degree of regional accuracy. “It would be like a normal weather forecaster saying it’s going to rain somewhere on the Earth sometime today,” Howard Singer, Chief Scientist of the Space Weather Prediction Center tells Popular Science.

The new model takes advantage of the position of the NOAA satellite DSCOVR, perhaps best known for capturing stunning images of Earth from its stable orbit at the Lagrange point L1, a spot one million miles away from Earth that is always positioned directly between the Earth and the Sun. From that position it can measure the magnitude of the magnetic field wrapped up in a solar storm.

“It’s like a buoy upstream of a coastline,” Singer says. The data from DSCOVR can be fed into the new model minute by minute, and give a regional heads-up to areas that will be more affected by the incoming solar disturbance than others.

When a solar storm hits the Earth, the magnetic fields in the storm interact with the magnetic fields of the Earth, generating electrical currents that can pass from the magnetosphere into the ionosphere, and from there into the Earth, which can act like a giant conductor. Our power grids, which are connected to the Earth, can intercept some of that current. If the equipment and operators aren’t prepared for an event, some of the equipment could fry, like a television in a lightning storm.

Not all areas of the Earth are affected by solar storms in quite the same way. If Canada is directly in the path of a storm, it might be more affected than, say, Australia, and power plants in Canada might want to take extra precautions, making sure that there is plenty of space on the grid to accommodate the increased current, and monitoring older transformers to make sure they don’t fry.

“A forecast that is granular to a regional level can be more effective because it can alert the right utilities of solar storms that could affect their operations,” Mark Olson, a Senior Standards Developer with the international regulatory group the North American Electric Reliability Corporation (NERC) tells Popular Science.

“There are regional factors that influence the impact that solar storms can have on the grid, like the latitude of the power system or the structure of the Earth in the area of the power system,” Olson says.

Lately, solar storms hitting the Earth have been relatively mild in their impacts, but we know that they can be very large and severe. In 2012, a large CME just missed the Earth, but hit a satellite called STEREO A, which recorded the whole thing, and collected data that indicated that the event would have caused a massive global disaster if it had hit the Earth, potentially overloading the grid and destroying transformers.

Giant CMEs have hit Earth in the past. One of the largest solar storms, known as the Carrington Event, happened in August and September of 1859, when a huge solar flare caused aurora to be seen as far south as Panama, and disrupted telegraph wires around the world.

Solar storms since then, in 1921, 1989, and 2003 have caused infrastructure damage, large blackouts and even, in 1967, brought us to the brink of war. But none of those were as large as the Carrington event.

Keep in mind that the Carrington event happened before the American Civil War, and that today we rely far more heavily on electricity than we did 157 years ago. If a similar event (like the one in 2012) caught our aging grid unaware, the increased electrical load has the potential to damage electrical transformers, potentially blacking out the energy system for an extended time, as transformers are neither inexpensive nor easy to manufacture.

Forecasters hope that the new system will give utilities enough time to react to prevent an extended blackout, and plan on refining the model as time goes on, eventually adding in information about the geology of various regions with the help of the USGS.

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The night is kind to radio. Free from the deadlock of rush-hour commercials, DJs can play with the format, delve into back catalogues, and mess around with B-sides. The night is also kind to radio listeners, especially those on the edge of service. When radio waves reach the ionosphere in the atmosphere, they can bounce down to earth, and on some nights where the ionosphere is dense with free electrons, that means radio signals can go farther.

The United States Air Force is interested in replicating this effect. While a more reliably dense ionosphere could help people trying to tune in a college radio station at the edge of its broadcast range, that’s probably not the the Air Force’s primary interest. Instead, an electron-rich ionosphere primarily means more range for the radios used by the military, and it might provide some protection for GPS signals against solar storms.

So how is the Air Force going to create that electron density? Tiny satellites, bombing the sky with plasma.

From New Scientist:

The project is in early stages, with three teams building different, cubesat-based approaches to this. The ultimate goal may be an on-demand fleet of cubesats that can strengthen the ionosphere when needed, but first the teams contracted by the Air Force has to prove the science works.

Then, and only then, can we begin bombing the ionosphere to save it.

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It’s been just over a year since the Earth’s first million-mile portrait was released.

Now the team working on NASA and NOAA’s Earth Polychromatic Imaging Camera (EPIC) on the Deep Space Climate Observatory (DSCOVR) have released a gorgeous time lapse video of the Earth over the course of that year. Jay Herman, the lead scientist for DSCOVR narrates the short video, explaining what we’re seeing over the course of the year.

NASA has been releasing daily images of Earth taken by the EPIC instrument, but this is the first time that a year’s worth of those pictures have all been stitched together.

In addition to awesome images, like the Moon photobombing the Earth, researchers are also collecting a lot of data about Earth’s climate from the satellite, situated in a stable orbit at a gravitationally steady point between the Earth and Sun.

DSCOVR, which was originally built in the late 1990’s and tabled due to budget cuts, launched in 2015, and is set to continue observing the Earth for many years to come.

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On the evening of July 11th, the scene on Manhattan’s 14th street was nearly riotous. Every minute or so, the traffic light changed and a crowd flooded the street, facing west with their iPhones above their head. The light changed again, the crowd dispersed, and a symphony of car horns tried to beckon any stragglers back onto the sidewalk. By 8:20 pm the honks were futile.

A confused businessman was describing what he saw into his phone. “What’s going on?” he asked me when he noticed I was giggling at his confusion. I explained that it was Manhattanhenge, and for the next to last time this year, the sunset was perfectly aligned with the grid of Manhattan. He backed away babbling in gibberish.

“Manhattanhenge” was popularized by the American Museum of Natural History’s Neil deGrasse Tyson and happens twice a year, a few weeks before and after the summer solstice. The number of Google searches for “Manhattanhenge” has increased exponentially in the past few years, says Jackie Faherty, research scientist who works on science outreach at AMNH, and the number of people flooding the streets of Manhattan during the event each year continues to increase. It creates a bit of a traffic and safety problem.

Crowd flooding the street, courtesy of Sara Chodosh

“You’ll notice that it’s becoming dangerous for everybody because you need to be in the street. I’d love to see more street closures on the days of Manhattanhenge,” Faherty told Popular Science.

Faherty lectured a group of several hundred people at the Hayden Planetarium at AMNH last night to explain the science and history of Manhattanhenge. The event occurs because of how the orientation of Manhattan’s grid aligns with the location of the Sun. The Earth spins on a tilt, so as it orbits the Sun and the year progresses, different parts are exposed to different amounts of sunlight. North of the equator, the longest days are in the summer, when the Sun is high in the sky and rises and sets north of east and west. As winter approaches, the Sun appears to move south and lower in the sky, until the winter solstice when its arc is shortest. Afterwards, the days grow longer as the Sun moves north, and the cycle continues.

The sunset lines up with the grid of Manhattan twice a year, on May 29th and 30th as the Sun moves toward the summer solstice and on July 11th and 12th as it returns southward. Between these days, the Sun will line up with the grid during the day, but higher in the sky. Other cities have “henges” on different days, so long as they have a grid pattern that that faces between the sunset’s southwestern and northwestern-most points. The term comes from Stonehenge in England, built so that the slabs align with the sunrise during the summer solstice and sunset during the winter solstice.

After the event, we went outside to 79th Street, closed to traffic by the community board of Manhattan’s Upper West Side and a far different scene from the first night of Manhattanhenge. A crowd of people stood, sat, and chatted in the center of a normally busy New York street watching the Sun cross diagonally from upper left to lower right and ultimately behind a building on the horizon across the Hudson River in New Jersey.

Faherty told me that initially she would go to her “secret spot,” Pershing Square, an overpass near Grand Central station. But recently, “it was flooded with hundreds of people.” She noted that the 79th Street spot has been closed to cars annually during the event since 2012, but the view wasn’t optimal. Many in the crowd groaned as a tall building across the river blocked the climax.

There are other Manhattanhenge-like events, though. Early risers can catch a grid-aligned sunrise over equally apartment-building-heavy Queens on days surrounding the winter solstice, and on some days the full moon rises along the grid, though predicting those dates is more difficult, said Faherty.

Manhattanhenge has two purposes: to get laypeople excited about astronomy and as a good photo op for Instagrammers or Pokemon Go players, so the best place to watch is a scenic street. “It’s an epic photograph with your favorite building,” Faherty told the crowd last night.

But what’s the real best way to view the phenomenon as more attendees flood Manhattan’s streets every year? “Safely,” said Faherty.

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The sun’s ultraviolet rays damage skin and hair. So both rely on a pigmented polymer called melanin for protection. Melanin both absorbs and scatters UV rays, keeping them away from your cells’ fragile DNA. But melanin degrades over time and loses its color from prolonged exposure.

In hair, the result is a bleached or yellowed effect. But because hair cells are dead—comprised only of lipids, water, pigments, and structural proteins—these light strands remain in this damaged state until new hair with fresh melanin grows to replace them.

Skin cells, on the other hand, are alive and can react and adapt to UV rays. When sun hits the skin, the body cranks out a hormone that binds to melanin-making cells, causing them to produce more melanin for addi­­tional protection. This melanin populates the lower epidermis and becomes darker as it disperses to the upper layers. Over time, this process leads to a suntan, which serves to protect you better.

Prolonged exposure to UV light can eventually damage skin’s cellular DNA, though, and those damaged cells put you at a higher risk for skin cancer. Tanning and repeated sunburns only multiply those risks. So feel free to sun your hair until it’s golden blond—but slather on that sunscreen.

This article was originally published in the May/June 2016 issue of Popular Science.

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Everyone knows not to look directly at the sun. It’s dangerous, and besides, that’s what we have NASA’s Solar Dynamics Observatory (SDO) for.

The SDO is a spacecraft that scientists use to study and monitor space weather, keeping a particular eye out for changes in the solar wind, which streams away from the sun, occasionally carrying magnetic fields that can disrupt communications or satellites near Earth.

Earlier this month, NASA spotted a huge coronal hole in the sun, and captured these gorgeous images over the course of two days from May 17 to May 19.

Coronal holes are areas where the Sun’s corona (the Sun’s atmosphere) is less dense, and has a lower temperature than the rest of the corona. These areas tend to send out the fastest solar winds. A coronal hole can’t be seen in visible light, but it can be spotted by observing ultraviolet light. In this case, the researchers have colored the ultraviolet light purple so that we can see it.

Solar Dynamics Observatory, NASA

There are huge holes in our knowledge of coronal holes. At present, researchers aren’t even sure how they form. Coronal holes aren’t particularly rare, but they do look magnificent. Take a look at another coronal hole spotted earlier this March:

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As part of NASA’s Magnetospheric Multiscale Mission, four spacecraft have been cruising through the boundary where the Earth’s magnetic field bumps up against the Sun’s for the past year. Like sending sensors into a storm, the idea is to learn more about the physics of what happens in the heart of the magnetosphere.

The coronal mass ejection of a solar flare sends fast moving solar particles with a strong magnetic field. Occasionally, those interact with our own planet’s magnetosphere and cause something called magnetic reconnection, which causes such phenomena as auroras.

Now, after 4,000 trips through the boundary, NASA’s probes have observed a magnetic reconnection event for first time. Flying in in a pyramid formation, the four spacecraft are equipped with 25 sensors each, to create a 3-D map of their surroundings.

“The decades-old mystery is what do the electrons do, and how do the two magnetic fields interconnect,” principal investigator Jim Burch said in a statement. “Satellite measurements of electrons have been too slow by a factor of 100 to sample the magnetic reconnection region. The precision and speed of the MMS measurements, however, opened up a new window on the universe, a new ‘microscope’ to see reconnection.”

With this new data, the scientists were able to determine that electrons shoot off, away from the reconnection event, in straight lines. They travel at speeds of hundreds of miles per second, and end up passing through magnetic boundaries that would usually deflect them. They travel through the new magnetic field for a ways before turning around and heading back home. So far, scientists’ understanding of magnetic reconnection has come from lab experiments and computer models. Now that they’ve been able to observe–and will continue to make more observations throughout the mission–scientists can start to gain a better understanding of the space environment. Which, NASA says, is all the more crucial for when humans begin to travel further from our home planet.

You can watch a rendering of this process in NASA’s video below:

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On the evening of April 17, the Solar Dynamics Observatory observed the solar dynamic above, and captured rather beautiful false-color 4K video of it.

Solar flares are caused–in some way–by magnetic disturbances in the sun, and can interfere with electromagnetic transmissions here on Earth, like the one you’re probably watching the video on right now.

Next, look at a gallery of our all-time favorite pictures of our favorite star, compiled by Josh Hrala, and, photographed by the Solar Dynamics Observatory, which has been snapping detailed pictures of the Sun since its launch in 2010.

Active Sun in 3D

Substantial Coronal Hole

Circular CME

The Sun’s Layers

Three Rotations

SDO Solar Eclipse

Dancing on a Star

Two X Flares

Active Regions

Active Regions Galore

Solar Eclipse

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The sun is weird. For some reason, every 11 years, solar activity ramps up. More sunspots and solar storms appear on the surface. The sun gets brighter and spews out higher levels of charged particles that could potentially take out Earth’s power grids.

The sun’s swirling magnetic field is at the heart of the phenomenon, and could hold the key to predicting and understanding it. That’s why scientists have been trying for decades to model solar magnetic activity in computer simulations, but it hasn’t been easy. Large-scale, low-resolution models seemed to match the sun’s behavior pretty well, but higher-resolution, small-scale models couldn’t account for what was happening at the large scale.

Now, with the help of a couple of supercomputers, scientists have created a model that works at both the small and large scales, and it might eventually help to predict the timing and intensity of solar activity. The research was published today in Science.

In an interview with Popular Science, Matthias Rempel, who studies solar variability at the National Center for Atmospheric Research and is a co-author on the study, explained what the problem was.

In the past, the large-scale simulations treated the sun’s surface material as if it was viscous like honey, instead of more fluid like water. But the small-scale simulations that more accurately treated the fluid as watery didn’t generate magnetic fields that made sense.

What Rempel and his colleagues found was that, if you increase the model resolution even further, then the small-scale magnetic fields actually make the solar fluids act as if it were viscous. Sort of like how water with seaweed in it can be more difficult to swim through, Rempel says. When the team’s model accounted for this stickiness, their small-scale simulations resulted in a larger magnetic field that made sense.

“It gives some justification for the earlier models,” says Rempel, “but it also tells us, if you want to model something like the sun, we really have to account for magnetic field on all scales, and even the smallest scales of the magnetic field play a crucial role for understanding the larger scale components.”

But the simulation isn’t perfect yet. “At his point it’s still very difficult in these simulations to get something which looks like the sun,” says Rempel. The model still doesn’t recapitulate the 11-year solar cycle, but it’s a step forward.

In the future, the team hopes it refined versions of the model will help explain how the solar cycle works and how it will evolve in the future.

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Is it a disco ball? A glowing hairball? An orb-like alien with tendrils?

Nope, that’s our sun.

In this video from NASA, solar researcher Holly Gilbert explains a gorgeous dynamic computer model of the Sun’s magnetic fields. The pink and green lines are open magnetic field lines, extending into space, while their counterparts, the white closed magnetic field lines emanate from and then circle back towards the sun’s surface.

In addition to just being fascinating, understanding how the Sun’s magnetic field works can help us better prepare for solar storms, or coronal mass ejections, events that can disrupt the function of electrical grids, GPS devices, and other technology here on Earth.

Researchers hope that computer models like this one, combined with observations from satellites, and even Cubesats will help make predicting and preparing for those events easier.

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Sure, the sun’s light and heat make life possible on Earth, and its gravity holds our entire solar system together. But our nearest star remains surprisingly enigmatic.

Scientists still don’t know, for example, why its magnetic activity fluctuates in an 11-year solar cycle. Or how powerful solar flares can knock out satellites, disrupt GPS systems, and fry electrical grids here on Earth.

What they do know is that sunspots—those randomly-spaced dark blotches on the sun’s surface—are a critical part of that puzzle. In September, an international team of scientists was able to show, for the first time, how magnetic activity in the sun’s interior leads a sunspot to form. And it revealed how that energy is later released in plasma jets and explosions, phenomena similar to powerful solar flares.

What are sunspots?

Sunspots are easily recognized as speckles on the surface of the sun. Scientists have known since the early 20th century that sunspots are actually bundles of intense magnetic field lines—the lines along which the forces of a magnet move. They can be as big as planets, too. “Sunspots are one of the most important pieces of the sun,” says Shin Toriumi, a scientist with the National Astronomical Observatory of Japan.

To dig deeper into sunspots and figure out how they work, Toriumi and colleagues combined data from NAOJ’s space-based Hinode solar telescope, which observes the solar surface, with data from NASA’s IRIS, a space telescope observing the sun’s chromosphere—that gassy middle layer of its atmosphere. Using the observations they had gathered from the two telescopes, they employed NASA’s Pleiades supercomputer to run numerical models that simulated a sunspot’s formation. The results allowed scientists to observe the never-before-seen interaction between two of the sun’s layers.

Solar Archipelago

How do sunspots work?

The combined data sets showed how magnetic field lines within the sun emerge at the surface as small bundles called pores. When two of these pores approach one another, they squeeze the plasma between them into a long structure called a light bridge. Eventually, as the squeezing continues, the bridges merge into a single, large sunspot.

The process of breaking and reconnecting the magnetic field lines triggers violent explosions that cause plasma to jet into the atmosphere. The magnetic fields can also trigger much bigger solar flares. Solar flares are the largest explosions in the solar system, and are so powerful they can actually disrupt our technological infrastructure here on Earth. X-rays from flares can interfere with radio communications, UV radiation can create more drag on satellites in orbit, and radio emission can actually make GPS measurements less precise.

“Data simulation allows you to make the connection between the layers you can observe, and what’s happening underneath them [in the sun’s interior],” says Matthias Rempel, a solar physicist at the High Altitude Observatory of the University Corporation for Atmospheric Research.

Can they predict solar flares?

Toriumi says the observations of these small plasma jets and explosions are a step toward better understanding damaging solar flares. “The basic physics are the same,” he says. Since both are caused by sunspots, researchers may one day be able to figure out how to better protect satellites and radio communication from the effects of solar flares. And yes, your GPS too.

The team next wants to better understand magnetic reconnection by observing magnetic field lines in the chromosphere, a key mission of Japan’s planned Solar-C space telescope.

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Solar flares are gorgeous, but the delicate fiery loops that we’ve observed during humanity’s brief study of the sun are nothing compared to what other, similar stars are up to.

In a recent paper, researchers detail their observations of ‘superflares’ on a binary star in our galaxy named KIC 9655129. These superflares are huge solar flares that are much larger than any that we’ve observed coming off our own sun.

But even though they differ in terms of magnitude, (a superflare might give off the energy of a billion-megaton bomb while our sun’s solar flares reach a piddling 100 million megaton-bomb) researchers discovered that the underlying processes that drive the superflares on other stars is the same basic engine that drives solar flares on our own stars–periodic oscillations of magnetically charged plasma within the interior of the sun. So, could it happen here? Maybe. But if it did, the results would be very bad.

“If the Sun were to produce a superflare it would be disastrous for life on Earth; our GPS and radio communication systems could be severely disrupted and there could be large scale power blackouts as a result of strong electrical currents being induced in power grids,” lead author of the paper, Chloë Pugh, said in a statement.

But stop your panicked screenplay writing. According to Pugh, “[T]he conditions needed for a superflare are extremely unlikely to occur on the Sun, based on previous observations of solar activity.”

And if the sun did ever produce a superflare, or just a really large regular flare, we’d at least have a little bit of warning that it’s headed our way. New forecasting techniques for solar weather combined with better observational equipment like the DSCOVR satellite means that even if the worst is on its way, we can still try to get ready for it.

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As you gaze toward the sky on Sunday night, the cooling fall air around you, perhaps a few leaves crunching beneath your feet, and—WAIT the moon is giant and red! Don’t worry, it’s not a sign of the end times. You’re witnessing a rare and exciting event.

On the evening of September 27, sky spectators in North America, South America, the Atlantic Ocean, Greenland, Europe, Africa, and the Middle East will be able to see the moon at its closest point to Earth (known as its perigee).

The moon reaches its perigee (and the apogee, which is its furthest point from Earth) about once a month. However, it does not always reach that point when it’s full. This week, we’re in luck. The full moon will appear about 14 percent larger in diameter than usual, and is thus called a super moon, or “Supermoon”. At the same time, the Earth will pass between the sun and the moon, creating a total lunar eclipse. It’s the fourth full lunar eclipse in a row (a.k.a. a tetrad), with no partial eclipses in between. Shadow will start falling on the moon at 8:11 p.m. EDT, the full eclipse will begin at 10:11 p.m. EDT, and it will peak at 10:47 p.m. EDT, according to NASA.

To make it even more exciting (or scary, depending on how you look at it), the moon will also appear red in what’s known as a “Blood Moon,” hence the moniker and hashtag #SuperBloodMoon, which NASA is using on social media to promote the occurrence, and which you can use to find people’s images of the rare event (note: not all may be authentic). For those of us outside the area where the Supermoon will be visible, and/or in urban centers where the lights on the ground may interfere with the sight above, NASA is also providing a helpful livestream of the sky from Griffith Observatory, California, beginning at 8 p.m. EDT.

Amateur astronomy site Shadow and Substance also has some helpful charts showing exactly where and when the “SuperBloodMoon” will be visible across the Earth.

According to a fun investigation by EarthSky.org, the menacing “Blood Moon” moniker comes from biblical prophecy. It also pretty accurately describes the color of the moon during the eclipse. The moon looks red during a total lunar eclipse mostly because of the Earth’s atmosphere. When the Earth passes directly between the sun and the moon, our home planet casts its shadow over the moon. If the Earth had no atmosphere, the moon would be dark, and basically invisible to the non-existent humans who would definitely not survive without the atmosphere.

The last time a supermoon eclipse took place was 1982, and if you miss this one, there won’t be another until 2033. NASA has a nice detailed set of videos to show when the magic happens in different time zones, so be sure to find your area and get your eyes on the sky.

Updated after publication to include an embed of NASA’s livestream, a link to Shadow and Substance, and additional details about the timing of the eclipse.

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Eiffel Prominence

Apparently the sun has been taking notes on the work of architect Gustave Eiffel.

Yesterday, photographer Göran Strand noticed an odd shape coming off the sun as he was photographing it in his backyard in Sweden:

Though the solar copy bore an uncanny resemblance to the tower in France, this particular shape was a solar prominence, a loop of ionized gas that projects out from the sun’s surface. Fittingly, the first observation of a solar prominence was made by a Swedish astronomer in 1733.

Solar prominences can be amazing displays and are usually massive. As you can see from the scale, this prominence was several times larger than the earth.

To create the image you see above, Strand took over 1000 photos of the sun and stacked the best 300 together to get the clear shot of the prominence. In order to get the details of the sun (instead of being blinded by looking at the sun through a telescope), photographers and astronomers use filters including a special kind called hydrogen alpha filters to get a richer view of the solar surface, which is mostly burning hydrogen. The filter works by blocking out most other wavelengths of light, only allowing a small amount of the light emitted by burning hydrogen to shine through.

In addition to Twitter, you can see more of Strand’s work on his website, Instagram, and Facebook.

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The first day of spring this year will bring planet Earth a special celestial treat.

Load this page around 4:30 a.m. ET on Friday, March 20, to watch a live video stream of 2015’s only total solar eclipse from the relative comfort of wherever you happen to be connected to the internet.

NASA is (of course) promoting the event, and the robotic telescope service Slooh is hosting the webcast. The group will be broadcasting live with expert commentary from the Faroe Islands. So set your alarm (and your coffee maker) to see an out-of-this-world show.

Aside from the thrill of being in the right place at the right time, the 2015 eclipse will actually be a huge strain and test for Europe’s solar power industry, which has been preparing for the event for months.

Check out the path of the eclipse in this cool gif that NASA created to see where the moon’s shadow will fall during the celestial event. The gray region is where a partial eclipse will be visible, and the tiny black dot is where earthly inhabitants can bask in totality:

If clouds don’t get in the way, those in the path of the moon’s full shadow can expect to see something like this:

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Two days ago, a pair of huge coronal mass ejections (CMEs) left the Sun and headed for Earth. This morning at around 10:00 am Eastern time the massive magnetic bubbles of gas slammed into the Earth’s atmosphere, interacting with our magnetic field and creating a geomagnetic storm that NOAA classifies as severe. Geomagnetic storms are ranked from G1 to G5, with G5 being the highest. Today’s storm was classified as a G4.

A G4-level geomagnetic storm could potentially cause a lot of damage. The effects listed by NOAA include potential disruption of the electric grid, tracking problems on spacecraft, and issues with GPS and radio.

Luckily, NOAA hasn’t gotten any dramatic reports of things like that happening today. Whew.

The most beautiful side effect of the storm is probably going on above you right now. Because the storm is so strong, it might be possible for people as far south as Tennessee and Oklahoma to catch a glimpse of the northern lights, which occur when charged particles from the Sun slam into Earth’s magnetic field. You’ll have the best chance of seeing the aurora if you can find a place with few clouds and no light pollution. Or, if that’s not possible, Space.com and the Slooh Community Observatory created a video of the aurora tonight in Iceland.

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Human eyes can’t (or at least shouldn’t) look directly at the sun, but NASA’s IRIS can. The Interface Region Imaging Spectrograph mission is the latest to fly into space to observe the solar atmosphere. Now, a little more than a year after it launched, the satellite has sent back a complex picture of a special region of the sun, just below its corona.

IRIS observes the sun’s ultraviolet radiation, which can’t be seen by human eyes, and most of which is absorbed by the Earth’s atmosphere before it reaches our home planet. The satellite studies the interface region between the sun’s visible surface, which is called the photosphere, and the corona, or the “crown” of light you can see during solar eclipses. Scientists think the interface region is key to a paradox about the sun: Its corona is thousands of times hotter than its photosphere, even though the corona is farther away from the heat-generating chemical reactions in the sun’s core. It would be as if the air across the room from your radiator were warmer than the surface of the radiator itself.

IRIS is supposed to give scientists a more detailed look at what the interface region might be doing to shuttle energy out to the corona. Its telescope measures the temperature, velocity, and density of material in the interface region. It’s able to see details as small as 150 miles across.

The journal Science published five papers today, all describing different kinds of activity happening in the interface region. In an essay for Science, solar physics researcher Louise Harra summarizes what the papers found:

For example, one paper found that the interface region fires off small, fast, fleeting jets of plasma. The jets have speeds of 50 to 155 miles per second and last just 20 to 80 seconds each. Yet they probably feed mass and energy into solar wind, the paper’s authors wrote, which streams off the corona to buffet Earth and the other planets in the solar system.

IRIS will continue to observe the sun for at least another year, until the summer of 2015.

IRIS’ First Image of the Sun, July 2013

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Jack-O’-Lantern Sun

The sun got into the Halloween spirit a little early this year, producing active spots that look like a jack-o’-lantern leer on October 8. The active spots give off more light and energy than the rest of the sun’s surface.

This visualization shows the sun’s activity in two wavelengths of light, 171 Angstroms and 193 Angstroms. Both wavelengths are in the extreme ultraviolet portion of the electromagnetic spectrum, which is what NASA normally studies.

Extreme ultraviolet light isn’t visible to the naked eye, but it can nevertheless affect human life. When the sun is particularly active, the high-energy photons of extreme UV light can heat the Earth’s atmosphere, creating additional drag on mankind’s orbiting satellites. Or the photons can break apart atoms and molecules in the atmosphere, creating ions that disrupt radio signals. Luckily for life on Earth, the atmosphere blocks most extreme ultraviolet light from reaching the planet.

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What’s the fastest way to understand space? According to NASA, it’s listening to the music of the spheres displayed as actual music. A program that converts astronomical data into sound is letting researchers blaze through years of data with ease. At NASA’s Goddard Space Flight Center, University of Michigan doctoral candidate Robert Alexander listens to audio files made from satellite data. The Wind spacecraft sits between Earth and the Sun, and records changes in the Sun’s magnetic field. Here’s how that becomes sound:

This mostly translates to white noise, but when there’s something anomalous, Alexander can hear it happen and make note of where in the file it happened. And Alexander isn’t the only one using data this way. In fact, he’s training other physicists who study the sun how to be active listeners. A similar project, onomatopoetically dubbed “PEEP,” wants to use sound as a monitoring tool, turning network activity into a gentle chorus of bird sounds, interrupted by frog croaks at the first sign of trouble.

Listen to a reverse shockwave headed toward the Sun below, and read more at NASA:

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Earth has a magnetic field, which begins at the core and stretches far out into space. Typically, this magnetic field is a useful shield for solar activity. However, if the Earth’s magnetic field bumps up against the sun’s magnetic field, all types of madness can ensue, including geomagnetic storms, or space weather that can affect the International Space Station.

This meeting of the magnetic fields is known as magnetic reconnection. During this process, the sun’s electrical currents can enter Earth’s atmosphere, and in the process, some of our own magnetic field gets stripped away. A new study from MIT and NASA, published in the journal _Science _this week, explores how a plume of plasma adds extra reinforcements to keep us earthlings safe during solar activity.

The plume is not terribly unlike a river, with particles that flow through a stream. “This higher-density, cold plasma changes about every plasma physics process it comes in contact with,” MIT Haystack Observatory associate director John Foster said in a statement. “It slows down reconnection, and it can contribute to the generation of waves that, in turn, accelerate particles in other parts of the magnetosphere. So it’s a recirculation process, and really fascinating.”

Since space weather events create radio wave distortion, scientists at the Haystack Observatory have been analyzing radio signals to determine plasma particle concentration, using the data to map the plasma plumes from Earth. While they have been performing the research for 10 years, the researchers note that this is still just an estimate. So the team matched the Earth-based research with space-based data, monitoring a solar storm last January. Three spacecraft crossed one point in the magnetic field where a plasma plume was estimated to be. Data from those craft confirmed that dense plasma plume, which extended to the place where Earth’s field met the solar storm.

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Our sun has really got a flair for flares lately. The third solar flare in two days peaked at 11:03 a.m. Eastern time Friday, and it was ranked as an X2.1. Solar flares come in classifications according to their x-ray brightness: C, M, and X (in order of increasing intensity). A previous flare came at this morning at 4:01 am Eastern time, which was an X1.7—an X2 is twice as intense as an X1. Flares of the X-class variety are known to cause radio degradation or blackouts. These were both, clearly, more intense than the M-class flare we wrote about yesterday. This week, NASA also released a video (below) taken in late September. The video depicts a 200,000 mile-long solar material filament that “rips through” the corona, leaving behind a (not-scary-at-all-sounding) canyon of fire. But let it be known, NASA concedes that no, the sun is not actually made of fire, but rather plasma.

So what is going on up there? We’re currently at the solar maximum—that time in the 11-year cycle when solar activity is at its greatest. But for scientists, it’s been a strange one, with limited sun spots. And, if you think back to a New York Times article from September, some were actually wondering why the solar maximum was so mild. Words like “halfhearted,” “dud,” “tranquil,” and “slacker” were thrown around to describe the star we orbit. Space scientist Joseph M. Kunches even told the Times, “You look at the Sun today and you say, ‘What?'”

Well, it seems like the sun has heard the tauntings of us mortals loud and clear.

While the talk of flares and canyons and mass ejections might sound frightening, this statement on NASA’s website might help calm you down: “Increased numbers of flares are quite common at the moment, since the sun is near solar maximum. Humans have tracked solar cycles continuously since they were discovered in 1843, and it is normal for there to be many flares a day during the sun’s peak activity.”

NOAA’s Space Weather Prediction Center is also monitoring the situation. As of the time of this writing, the SWPC says there’s no sign of a coronal mass ejection from the latest flare , and that they’re unlikely to cause geomagnetic storm activity that will affect Earthlings, but we’re still awaiting minor effects from an ejection earlier this week, which could hit some time today.

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The planetary world keeps getting stranger. Scientists have found free-floating planets — drifting alone, away from stars — before. But the “newborn” PSO J318.5-22 (only 12 million years old) shows properties similar to other young planets around young stars, even though there is no star nearby the planet.

“We have never before seen an object free-floating in space that that looks like this. It has all the characteristics of young planets found around other stars, but it is drifting out there all alone,” stated team leader Michael Liu, who is with the Institute for Astronomy at the University of Hawaii at Manoa. “I had often wondered if such solitary objects exist, and now we know they do.”

The planet is about 80 light-years from Earth, which is quite close, and is part of a star group named after Beta Pictoris that also came together about 12 million years ago. There is a planet in orbit around Beta Pictoris itself, but PSO J318.5-22 has a lower mass and likely had a different formation scenario, the researchers said.

Astronomers uncovered the planet, which is six times the mass of Jupiter, while looking for brown dwarfs or “failed stars.” PSO J318.5-22′s ultra-red color stood apart from the other objects in the survey, astronomers said.

The telescope was identified in the Pan-STARRS 1 wide-field survey telescope in Maui. Follow-up observations were performed with several other Hawaii-based telescopes, including the NASA Infrared Telescope Facility, the Gemini North Telescope, and the Canada-France-Hawaii Telescope.

The discovery will soon be detailed in Astrophysical Letters, but for now you can read the prepublished verison on Arxiv.

Source: Institute for Astronomy at the University of Hawaii

This article was republished with permission from Universe Today.

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