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      Here’s why some supermassive black holes blaze so brightly

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      For the first time, astronomers have observed how certain supermassive black holes launch jets of high-energy particles into space — and the process is shocking.

      Shock waves propagating along the jet of one such blazar contort magnetic fields that accelerate escaping particles to nearly the speed of light, astronomers report November 23 in Nature. Studying such extreme acceleration can help probe fundamental physics questions that can’t be studied any other way.

      Blazars are active black holes that shoot jets of high-energy particles toward Earth, making them appear as bright spots from millions or even billions of light-years away (SN: 7/14/15). Astronomers knew that the jets’ extreme speeds and tight columnated beams had something to do with the shape of magnetic fields around black holes, but the details were fuzzy.

      Enter the Imaging X-Ray Polarimetry Explorer, or IXPE, an orbiting telescope launched in December 2021. Its mission is to measure X-ray polarization, or how X-ray light is oriented as it travels through space. While previous blazar observations of polarized radio waves and optical light probed parts of jets days to years after they’d been accelerated, polarized X-rays can see into a blazar’s active core (SN: 3/24/21).

      “In X-rays, you’re really looking at the heart of the particle acceleration,” says astrophysicist Yannis Liodakis of the University of Turku in Finland. “You’re really looking at the region where everything happens.”

      In March 2022, IPXE looked at an especially bright blazar called Markarian 501, located about 450 million light-years from Earth.

      Liodakis and colleagues had two main ideas for how magnetic fields might accelerate Markarian 501’s jet. Particles could be boosted by magnetic reconnection, where magnetic field lines break, reform and connect with other nearby lines. The same process accelerates plasma on the sun (SN: 11/14/19). If that was the particle acceleration engine, the polarization of light should be the same along the jet in all wavelengths, from radio waves to X-rays.

      Another option is a shock wave shooting particles down the jet. At the site of the shock, the magnetic fields suddenly switch from turbulent to ordered. That switch could send particles zooming away, like water through the nozzle of a hose. As the particles leave the shock site, turbulence should take over again. If a shock was responsible for the acceleration, short wavelength X-rays should be more polarized than longer wavelength optical and radio light, as measured by other telescopes.

      The IXPE spacecraft (illustrated) observed polarized X-rays come from a blazar and its jet. The inset illustrates how particles in the jet hit a shock wave (white) and get boosted to extreme speeds, emitting high-energy X-ray light. As they lose energy, the particles emit lower energy light in visible, infrared and radio wavelengths (purple and blue), and the jet becomes more turbulent.Pablo Garcia/MSFC/NASA

      That’s exactly what the researchers saw, Liodakis says. “We got a clear result,” he says, that favors the shock wave explanation.

      There is still work to do to figure out the details of how the particles flow, says astrophysicist James Webb of Florida International University in Miami. For one, it’s not clear what would produce the shock. But “this is a step in the right direction,” he says. “It’s like opening a new window and looking at the object freshly, and we now see things we hadn’t seen before. It’s very exciting.” More

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      The pristine Winchcombe meteorite suggests that Earth’s water came from asteroids

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      Late in the evening of February 28, 2021, a coal-dark space rock about the size of a soccer ball fell through the sky over northern England. The rock blazed in a dazzling, eight-second-long streak of light, split into fragments and sped toward the Earth. The largest piece went splat in the driveway of Rob and Cathryn Wilcock in the small, historic town of Winchcombe.

      An analysis of those fragments now shows that the meteorite came from the outer solar system, and contains water that is chemically similar to Earth’s, scientists report November 16 in Science Advances. How Earth got its water remains one of science’s enduring mysteries. The new results support the idea that asteroids brought water to the young planet (SN: 5/6/15).

      The Wilcocks were not the only ones who found pieces of the rock that fell that night. But they were the first. Bits of the Winchcombe meteorite were collected within 12 hours after they hit the ground, meaning they are relatively uncontaminated with earthly stuff, says planetary scientist Ashley King of London’s Natural History Museum.

      The first bits of the Winchcombe meteorite to be recovered were from Rob and Cathryn Wilcock’s driveway in England. The meteorite was so brittle it shattered on impact and made only a small dent in the driveway.R. Wilcock

      Other meteorites have been recovered after being tracked from space to the ground, but never so quickly (SN: 12/20/12).

      “It’s as pristine as we’re going to get from a meteorite,” King says. “Other than it landing in the museum on my desk, or other than sending a spacecraft up there, we can’t really get them any quicker or more pristine.”

      After collecting about 530 grams of meteorite from Winchcombe and other sites, including a sheep field in Scotland, King and colleagues threw a kitchen sink of lab techniques at the samples. The researchers polished the material, heated it and bombarded it with electrons, X-rays and lasers to figure out what elements and minerals it contained.

      The team also analyzed video of the fireball from the UK Fireball Alliance, a collaboration of 16 meteor-watching cameras around the world, plus many more videos from doorbell and dashboard cameras. The films helped to determine the meteorite’s trajectory and where it originated.

      The meteorite is a type of rare, carbon-rich rock called a carbonaceous chondrite, the team found. It came from an asteroid near the orbit of Jupiter, and got its start toward Earth around 300,000 years ago, a relatively short time for a trip through space, the researchers calculate.

      Chemical analyses also revealed that the meteorite is about 11 percent water by weight, with the water locked in hydrated minerals. Some of the hydrogen in that water is actually deuterium, a heavy form of hydrogen, and the ratio of hydrogen to deuterium in the meteorite is similar to that of the Earth’s atmosphere. “It’s a good indication that water [on Earth] was coming from water-rich asteroids,” King says.

      Researchers also found amino acids and other organic material in the meteorite pieces. “These are the building blocks for things like DNA,” King says. The pieces “don’t contain life, but they have the starting point for life locked up in them.” Further studies can help determine how those molecules formed in the asteroid that the meteorite came from, and how similar organic material could have been delivered to the early Earth.

      “It’s always exciting to have access to material that can provide a new window into an early time and place in our solar system,” says planetary scientist Meenakshi Wadhwa of Arizona State University in Tempe, who was not involved in the study.

      She hopes future studies will compare the samples of the Winchcombe meteorite to samples of asteroids Ryugu and Bennu, which were collected by spacecraft and sent back to Earth (SN: 1/15/19). Those asteroids are both closer to Earth than the main asteroid belt, where the Winchcombe meteorite came from. Comparing and contrasting all three samples will build a more complete picture of the early solar system’s makeup, and how it evolved into what we see today. More

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      Astronomers have found the closest known black hole to Earth

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      The closest black hole yet found is just 1,560 light-years from Earth, a new study reports. The black hole, dubbed Gaia BH1, is about 10 times the mass of the sun and orbits a sunlike star.

      Most known black holes steal and eat gas from massive companion stars. That gas forms a disk around the black hole and glows brightly in X-rays. But hungry black holes are not the most common ones in our galaxy. Far more numerous are the tranquil black holes that are not mid-meal, which astronomers have dreamed of finding for decades. Previous claims of finding such black holes have so far not held up (SN: 5/6/20; SN: 3/11/22).

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      So astrophysicist Kareem El-Badry and colleagues turned to newly released data from the Gaia spacecraft, which precisely maps the positions of billions of stars (SN: 6/13/22). A star orbiting a black hole at a safe distance won’t get eaten, but it will be pulled back and forth by the black hole’s gravity. Astronomers can detect the star’s motion and deduce the black hole’s presence.

      Out of hundreds of thousands of stars that looked like they were tugged by an unseen object, just one seemed like a good black hole candidate. Follow-up observations with other telescopes support the black hole idea, the team reports November 2 in Monthly Notices of the Royal Astronomical Society.

      Gaia BH1 is the nearest black hole to Earth ever discovered — the next closest is around 3,200 light-years away. But it’s probably not the closest that exists, or even the closest we’ll ever find. Astronomers think there are about 100 million black holes in the Milky Way, but almost all of them are invisible. “They’re just isolated, so we can’t see them,” says El-Badry, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

      The next data release from Gaia is due out in 2025, and El-Badry expects it to bring more black hole bounty. “We think there are probably a lot that are closer,” he says. “Just finding one … suggests there are a bunch more to be found.” More

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      Marsquakes hint that the planet might be volcanically active after all

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      Mars might be, geologically speaking, not quite dead.

      Researchers have analyzed a slew of recent temblors on the Red Planet and shown that these Marsquakes are probably caused by magma moving deep under the Martian surface. That’s evidence that Mars is still volcanically active, the researchers report October 27 in Nature Astronomy.

      Since touching down on Mars four years ago, NASA’s InSight lander has detected more than 1,000 Marsquakes (SN: 11/26/18). Its seismometer records seismic waves, which reveal information about a temblor’s size and location.

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      Previous studies have determined that several Marsquakes originated from a swath of Martian terrain known as Cerberus Fossae (SN: 5/13/22). This region, which is particularly riddled with faults, is more than 1,000 kilometers from the InSight lander.

      But most of the Marsquakes linked to Cerberus Fossae so far have been pretty familiar, scientifically speaking, says Anna Mittelholz, a planetary scientist at Harvard University. Their seismic waves, which are low frequency, “are ones that look much more like what we see for an earthquake,” she says.

      Mittelholz and her colleagues have now analyzed a large sample of Marsquakes, including more than 1,000 high-frequency temblors, which look nothing like their earthly brethren. To better understand the origin of the high-frequency quakes, the researchers added together their relatively weak signals. In that stack of seismic waves, the researchers saw a peak in the amount of seismic energy coming from the direction of Cerberus Fossae. That was an impressive undertaking, says Hrvoje Tkalčić, a geophysicist at the Australian National University in Canberra who was not involved with the research. “No study before this one attempted to locate the high-frequency quakes.”

      The fact that different types of Marsquakes are all concentrated in one region is a surprise. Previous research has suggested that Marsquakes might be due to Mars’ surface cooling and shrinking over time. That process, which occurs on the moon, would produce temblors evenly spread over the planet, Mittelholz says (SN: 5/13/19). “The expectation was that Marsquakes would originate from all over the place.”

      And by comparing the seismic waves that InSight measured with the seismic waves produced in different regions on our own planet, the researchers further showed that the low-frequency Marsquakes are probably produced by magma moving several tens of kilometers below Mars’ surface. “Our results are much more consistent with data from volcanic regions on Earth,” Mittelholz says.

      Rather than being a geologically dead planet, as some have suggested, Mars might be a surprisingly dynamic place, the researchers conclude. This finding rewrites our understanding of Mars, Mittelholz says, and there’s still so much more to learn about our celestial neighbor. “We’re only scratching the surface.”   More

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      Ancient bacteria could persist beneath Mars’ surface

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      Radiation-tolerant microbes might be able to live beneath Mars’ surface for hundreds of millions of years and may yet persist today, thanks in part — counterintuitively — to the Red Planet’s frigid, arid conditions.

      In addition to being cold and dry, the Martian surface is constantly bombarded by cosmic rays, charged particles and other radiation from space. Previous studies have shown that desiccation vastly extends a microbe’s potential for surviving by limiting the production of highly reactive oxygen-bearing chemicals that can damage proteins and DNA, among other vital molecules within its tissues. To see how long microbes might survive such an onslaught on Mars, researchers desiccated five species of bacteria and one type of yeast, stored them at −80° Celsius and then irradiated them.  

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      Some of the microbes might remain viable for only a few tens of thousands of years, experiments showed. But one species — Deinococcus radiodurans, a particularly radiation-hardy greebly that some scientists have nicknamed “Conan the bacterium” — might survive for as long as 280 million years if protected from radiation at soil depths of 10 meters or more, physical chemist Brian Hoffman and colleagues report online October 25 in Astrobiology.

      D. radiodurans resists radiation damage by having multiple copies of chromosomes and other genetic material in each cell, as well as high levels of manganese-bearing antioxidants that help remove DNA-damaging chemicals (SN: 9/3/10). If similar microbes evolved on Mars, they too could persist for lengthy intervals, even possibly until now — which is “improbable but not impossible,” says Hoffman, of Northwestern University in Evanston, Ill.

      Even if microbes that evolved on Mars ultimately succumbed to the harsh conditions, remnants of their proteins or other macromolecules may remain — offering hope that future missions, if equipped with the proper equipment, might be able to detect those signs of former life.     More

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      These are our top space images of all time

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      We’ve never seen images of space as astounding as those from the James Webb Space Telescope, which shared its first cosmic vistas in July. The pictures have left us dazzled, awestruck and excited for more. They also inspired us to reflect on the top space images past and present. These images have moved us because of their drama, beauty or significance. Here’s how eight Science News staffers answered the question: What’s your favorite space image of all time?

      Apollo 8 Earthrise, taken in 1968

      The Apollo 8 crew orbited the moon 10 times during late December of 1968, capturing this view of Earth.NASA

      Lisa Grossman, astronomy writer, chose Apollo 8’s Earthrise as her top space image. She says: The you-are-there, sci-fi-but-it’s-real feeling of seeing Earth over the edge of the moon gets my imagination going. And something about having the surface of the moon in the image gives me deep chills. I can imagine my own feet in those gray craters, my own eyes looking back at my own Earth. It’s wild. It’s eerie. I love it.

      I feel similarly about the selfie images from the Mars rovers; here’s NASA’s Curiosity rover at Mont Mercou in 2021.

      NASA’s Curiosity rover used a camera on its head and one on its robotic arm to create this selfie with Mont Mercou in March 2021.NASA, JPL-Caltech, MSSS

      You can see the rover and the landscape behind it. That’s our robotic avatar on that planet, rolling around doing our work. Though I’m lukewarm about sending people to do extraterrestrial exploration – I think the risks outweigh the scientific benefits – I have always been a sucker for imagining living on another world. Or at least visiting.

      JWST’s close-up of Neptune, taken in 2022

      Neptune and its rings glow in infrared light in this image from the James Webb Space Telescope. It’s the first direct look at Neptune’s rings in more than 30 years.NASA, ESA, CSA, STSCI, JOSEPH DEPASQUALE/STSCI

      Nikk Ogasa, staff writer for physical sciences, says: There are so many awe-inspiring space images out there, but my favorite from this year was the James Webb Space Telescope’s heavenly shot of Neptune. It is stunning. The image captures the planet’s near-infrared glow in unprecedented detail. Not only can you see the glorious rings, but you can also pick out high-flying methane clouds as bright streaks. It blows my mind that we can see clouds on another world that is billions of miles away.

      Pillars of Creation, first captured in 1995

      After capturing the Pillars of Creation in 1995, the Hubble Space Telescope imaged them for a second time in late 2014 (the image in visible light is shown here).NASA, ESA and the Hubble Heritage Team, STSCI/AURA

      Two members of our team selected the Hubble Space Telescope’s second view of the Pillars of Creation, taken in 2014, as their top space image.

      Design director Erin Otwell says: My top space image is the Pillars of Creation in the Eagle Nebula. It’s my choice because of the awe-inspiring details and the painterly quality of the composition. To me, this image sums up the feeling of studying the cosmos and of creation itself. The towers of gas and dust where new stars are being born compose an almost solid-looking figure. It looks more like a hand than pillars.  

      Maria Temming, assistant editor at Science News Explores, says: I know that claiming the Pillars of Creation as my favorite space image is like saying Starbucks is my favorite coffee. But I don’t care! I love it. I have something of a sentimental attachment to this vista, since it was on the cover of the Great Courses intro to astronomy DVD set that first sparked my interest in space science.

      In an infrared light view of the Pillars of Creation, taken by the Hubble Space Telescope in late 2014, stars in and behind the towers of gas and dust are visible.NASA, ESA, Hubble and the Hubble Heritage Team

      The iconic, candy-colored images of the pillars in visible light are not the only versions that Hubble has captured. In 2014, the space telescope also took a ghostly picture of the scene in infrared light (above). Light at infrared wavelengths shines through the pillars’ gas and dust, revealing the baby stars swaddled inside these clouds.

      Thomas Digges’ view of the universe, published in 1576

      In this image published in 1576, English astronomer Thomas Digges depicts stars extending far beyond the solar system.Wellcome Collection

      Tom Siegfried, contributing correspondent, chose this diagram as his favorite space image. He says: When Copernicus displaced the Earth from the center of the universe, he pictured the stars as occupying a sphere surrounding the planets that orbited on smaller spheres surrounding the sun. But Thomas Digges, an English astronomer who defended Copernicus, believed the stars extended far beyond the solar system.

      In this image, published in 1576, Digges depicted numerous stars beyond the spheres of the planets, suggesting that the universe was “garnished with lights innumerable and reaching up in spherical altitude without end.” With these words Digges was the first follower of Copernicus to suggest that the universe encompassed an infinite expanse of space.

      The Milky Way’s black hole, released in 2022

      In May 2022, the Event Horizon Telescope collaboration released this first image of the black hole at the heart of the Milky Way.EVENT HORIZON TELESCOPE COLLABORATION

      Helen Thompson, associate digital editor, says: Is it extremely blurry? Yes. Is it not even the first time we’ve imaged a black hole? Also yes. But it’s the black hole in our galactic backyard, and we’d never seen it before. There’s something mind-blowing and kind of heartwarming about seeing it for the first time. The Event Horizon Telescope’s first image of Sagittarius A* might not be as pretty as James Webb’s fancy-schmancy pictures, but all of the difficulties that come with imaging black holes and especially this black hole make it so compelling.

      Gravitational lensing of quasar 2M1310-1714, captured in 2021

      Thanks to gravitational lensing, predicted by Einstein’s general theory of relativity before it was observed, quasar 2M1310-1714 appears as four points of light sitting on a ring around two bright galaxies.ESA, Hubble, NASA, T. Treu

      Elizabeth Quill, special projects editor, says: Within the ring of light at the center of this image are a pair of distant galaxies and a much more distant quasar behind them. The mass of the galactic duo is warping the fabric of spacetime, bending and magnifying the quasar’s light to form what are four separate images of the quasar, each sitting around the ring. It’s a visually powerful example of a phenomenon known as gravitational lensing, which was predicted by Einstein’s general theory of relativity before it was ever observed.

      My top space image wows me every time. How incredible that the universe works this way. How incredible that the human mind, a motley product of the universe, could foresee it. And not only foresee it; today’s scientists use gravitational lensing as a tool to study otherwise inaccessible regions of space. It’s both humbling and empowering.

      Pale Blue Dot, taken in 1990

      NASA’s Voyager 1 spacecraft took this parting image of Earth after completing its tour of the solar system in 1990.NASA, JPL-Caltech

      Christopher Crockett, associate news editor, says: My favorite space image of all time isn’t of a colorful nebula, or a glittering galaxy, or even a certain supermassive black hole. It’s a single dot, seemingly ensconced in a shaft of light.

      After completing its tour of the solar system in 1990, NASA’s Voyager 1 looked back and took a series of parting images – a “family portrait,” it was called – of several planets orbiting our sun. One of the images, which came to be known as the “pale blue dot” photo, captured Earth as seen from roughly 6 billion kilometers away — the most distant image of home anyone has ever taken.

      The image, updated with modern image-processing software and re-released in 2020 (above), remains a reminder of why we explore the universe. Yes, we want to better understand how space and time, stars and planets, galaxies and superclusters work, because we’re curious. But all those questions ultimately come back to trying to understand where we come from and how we fit into all that surrounds us.

      As Carl Sagan emphasized, nothing better captures just how tiny we are in the grand scheme of things than seeing our entire planet reduced to a mere speck of light.

      When I used to give public talks about astronomy, I almost always closed with this image. And I would usually read from Sagan’s reflections on it:

      “Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.… on a mote of dust suspended in a sunbeam.… There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.” More

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      Meet the BOAT, the brightest gamma-ray burst of all time

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      The brightest gamma-ray burst ever recorded recently lit up a distant galaxy — and astronomers have nicknamed it the BOAT, for Brightest of All Time.

      “We use the boat emoji a lot when we’re talking about it” on the messaging app Slack, says astronomer Jillian Rastinejad of Northwestern University in Evanston, Ill.

      Gamma-ray bursts are energetic explosions that go off when a massive star dies and leaves behind a black hole or neutron star (SN: 11/20/19; SN: 8/2/21). The collapse sets off jets of gamma rays zipping away from the poles of the former star. If those jets happen to be pointed right at Earth, astronomers can see them as a gamma-ray burst.

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      This new burst, officially named GRB 221009A, was probably triggered by a supernova giving birth to a black hole in a galaxy about 2 billion light-years from Earth, researchers announced October 13. Astronomers think it released as much energy as roughly three suns converting all of their mass to pure energy.

      NASA’s Neil Gehrels Swift Observatory, a gamma-ray telescope in space, automatically detected the blast October 9 around 10:15 a.m. EDT, and promptly alerted astronomers that something strange was happening.

      “At the time, when it went off, it looked kind of weird to us,” says Penn State astrophysicist Jamie Kennea, who is the head of science operations for Swift. The blast’s position in the sky seemed to line up with the plane of the Milky Way. So at first Kennea and colleagues thought it was within our own galaxy, and so unlikely to be something as dramatically energetic as a gamma-ray burst. If a burst like this went off inside the Milky Way, it would be visible to the naked eye, which wasn’t the case.

      But soon Kennea learned that NASA’s Fermi Gamma-ray Space Telescope had also seen the flash — and it was one of the brightest things the telescope had ever seen. A fresh look at the Swift data convinced Kennea and colleagues that the flash was the brightest gamma-ray burst seen in the 50 years of observing these rare explosions.

      “It’s quite exceptional,” Kennea says. “It stands head and shoulders above the rest.”

      This series of visible-light images from NASA’s Swift telescope’s ultraviolet/optical instrument shows that the bright glow of the gamma-ray burst GRB 221009A (yellow circle) faded over about 10 hours.Swift/NASA, B. Cenko

      After confirmation of the burst’s BOAT bonafides — a term coined by Rastinejad’s adviser, Northwestern astronomer Wen-fai Fong — other astronomers rushed to get a look. Within days, scientists around the world got a glimpse of the blast with telescopes in space and on the ground, in nearly every type of light. Even some radio telescopes typically used as lightning detectors saw a sudden disturbance associated with GRB 221009A, suggesting that the burst stripped electrons from atoms in Earth’s atmosphere.

      In the hours and days after the initial explosion, the burst subsided and gave way to a still relatively bright afterglow. Eventually, astronomers expect to see it fade even more, replaced by glowing ripples of material in the supernova remnant.

      The extreme brightness was probably at least partially due to GRB 221009A’s relative proximity, Kennea says. A couple billion light-years might seem far, but the average gamma-ray burst is more like 10 billion light-years away. It probably was also just intrinsically bright, though there hasn’t been time to figure out why.

      Studying the blast as it changes is “probably going to challenge some of our assumptions of how gamma-ray bursts work,” Kennea says. “I think people who are gamma-ray burst theorists are going to be inundated with so much data that this is going to change theories that they thought were pretty solid.”

      GRB 221009A will move behind the sun from Earth’s perspective starting in late November, shielding it temporarily from view. But because its glow is still so bright now, astronomers are hopeful that they’ll still be able to see it when it becomes visible again in February.

      “I’m so excited for a few months from now when we have all the beautiful data,” Rastinejad says. More