Astro Blog

https://www.nytimes.com/2022/12/27/science/astronomy-webb-telescope.html By  Dennis Overbye , The New York Times.  Excerpt: So far it’s been eye candy from heaven: The black vastness of space teeming with enigmatic, unfathomably distant blobs of light. Ghostly portraits of Neptune, Jupiter and other neighbors we thought we knew already. Nebulas and galaxies made visible by the penetrating infrared eyes of the James Webb Space Telescope. ...For three days in December, some 200 astronomers filled an auditorium at the institute to hear and discuss the first results from the telescope. ...Galaxies that, even in their relative youth, had already spawned supermassive black holes. Atmospheric studies of some of the seven rocky exoplanets orbiting Trappist 1, a red dwarf star that might harbor habitable planets. (Data suggest that at least two of the exoplanets lack the bulky primordial hydrogen atmospheres that would choke off life as we know it, but they may have skimpy atmospheres of denser

https://www.science.org/content/article/mars-had-long-lived-magnetic-field-extending-chances-life By Zack Savitsky, Science.  Excerpt: Once upon a time, scientists believe, Mars was far from today’s cold, inhospitable desert. Rivers carved canyons, lakes filled craters, and a magnetic field may have fended off space radiation, keeping it from eating away the atmospheric moisture. As the martian interior cooled, leading theories hold, its magnetic field died out, leaving the atmosphere undefended and ending this warm and wet period, when the planet might have hosted life. But researchers can’t agree on when that happened. Now, fragments from a famous martian meteorite, studied with a new kind of quantum microscope, have yielded evidence that the planet’s field persisted until 3.9 billion years ago, hundreds of millions of years longer than many had thought. The clues in the meteorite, a Mars rock that ended up on Earth after an impact blasted it from its home planet, could extend Mars’s

https://eos.org/articles/nasas-perseverance-rover-records-the-first-sounds-of-a-dust-devil-on-mars By Jon Kelvey , Eos/AGU.  Excerpt: In a stroke of luck, the SuperCam microphone on Perseverance was turned on the moment a dust devil swept directly over the rover. ...

https://eos.org/research-spotlights/long-lived-lakes-reveal-a-history-of-water-on-mars By  Sarah Derouin , Eos/AGU.  Excerpt: The northern hemisphere of Mars is divided into two broadly distinctive areas: the smooth northern lowlands and the pockmarked southern highlands. The region of  Arabia Terra  ...is thought to contain some of the planet’s oldest rocks, at more than 3.7 billion years old. Among the craters in the southern highlands, valleys and paleolakes abound, exposing sedimentary and geomorphologic evidence of liquid water. However, relatively few paleolakes have been identified in Arabia Terra.  Dickeson et al.  ...describe seven new paleolakes in the region. The researchers focused on paleolake features including lake levels, drainage catchments, fans, and lake outlets. ...There was evidence of surface water inflows that filled the lakes as well as outlet streams that drained them, forming a cascading chain of lakes. The team also observed multiple past water levels within

https://www.scientificamerican.com/article/the-best-of-jwsts-cosmic-portraits/ By Clara Moskowitz , Scientific American.  Excerpt: [Images Jupiter, Neptune and their rings as well as the phantom galaxy, M74.]

https://www.theguardian.com/science/2022/nov/16/meteorite-that-landed-in-cotswolds-may-solve-mystery-of-earths-water By  Hannah Devlin , The Guardian.  Excerpt: Water covers three-quarters of the Earth’s surface and was crucial for the emergence of life, but its origins have remained a subject of active debate among scientists. Now, a 4.6bn-year-old rock that crashed on to a  driveway in Gloucestershire last year  has provided some of the most compelling evidence to date that water arrived on Earth from asteroids in the outer solar system.... 

https://www.nasa.gov/press-release/liftoff-nasa-s-artemis-i-mega-rocket-launches-orion-to-moon NASA  RELEASE 22-117 .  Excerpt: Following a successful launch of NASA’s Space Launch System (SLS), the most powerful rocket in the world, the agency’s Orion spacecraft is on its way to the Moon as part of the Artemis program. Carrying an uncrewed Orion, SLS lifted off for its flight test debut at 1:47 a.m. EST Wednesday from Launch Pad 39B at NASA’s Kennedy Space Center in Florida. The launch is the first leg of a mission in which Orion is planned to travel approximately 40,000 miles beyond the Moon and return to Earth over the course of 25.5 days. Known as  Artemis I , the mission is a critical part of NASA’s Moon to Mars exploration approach, in which the agency explores for the benefit of humanity. It’s an important test for the agency before flying astronauts on the  Artemis II  mission.... 

https://eos.org/articles/a-day-in-the-life-used-to-be-17-hours By Emily Shepherd , Eos/AGU.  Excerpt: The Moon was a lot closer to Earth 2.46 billion years ago, and the shorter distance contributed to shorter days. ...new research has calculated the distance of the Moon 2.46 billion years ago, nearly doubling the age of the previous estimate. Because the length of the day is tightly, tidally tied to the location of the Moon, the research has also calculated how long a day lasted at the time: 17 hours. ...To determine the distance of the Moon, scientists studied rhythmic patterns in Earth’s orbit and axis called  Milankovitch cycles , explained  Margriet Lantink , a geologist at the University of Wisconsin–Madison and lead author of the  new study in the  Proceedings of the National Academy of Sciences of the United States of America ....

https://gss.lawrencehallofscience.org/ac7-planet-star-systems/ Near the top of this page you can find links to some nifty activities from the Astronomical Society of the Pacific, Night Sky Network.… 

https://www.nytimes.com/2022/11/03/movies/good-night-oppy-review.html By  Ben Kenigsberg , The New York Times Excerpt: NASA’s  Opportunity Rover  landed on Mars in January 2004 and chugged along for more than 14 years before giving out. (In February 2019, NASA  declared the mission over .) Opportunity’s anticipated time in service — a span that Steve Squyres, the principal investigator for the mission, is heard likening in  “Good Night Oppy ” to a warranty — was only around 90 days. Oppy, and to a lesser extent its sister rover, Spirit, which “died” several years earlier, was the robot geologist that refused to quit.  Neither rover, alas, shot cinematic-quality footage of the red planet, but in this documentary from Ryan White ( “Assassins,”   on the killing of Kim Jong-nam), visual effects work from Industrial Light & Magic allows viewers to imagine they’re exploring craters and bedrock right alongside the androids. ... the way “Good Night Oppy” anthropomorphizes   the robots migh

https://www.nytimes.com/2022/10/31/science/asteroid-planet-killer.html By Robin George Andrews , The New York Times.  Excerpt: Last year, in the hope of finding asteroids cloaked by excessive sunlight, an international team of astronomers co-opted a camera primarily designed to investigate the universe’s notoriously elusive dark energy. In  an announcement Monday  based on a survey first published in September in  The Astronomical Journal , the researchers announced the discovery of three new light-drowned projectiles. One of them, 2022 AP7, is roughly a mile long, and its orbit crosses Earth’s path around the sun, getting as near as 4.4 million miles to Earth itself — uncomfortably close by cosmic standards (although far more distant than Earth’s moon). That makes 2022 AP7 “the largest potentially hazardous asteroid found in the last eight years or so,” said  Scott Sheppard , an astronomer at the Carnegie Institution for Science in Washington, D.C., and an author of the study. ...“The

https://www.nytimes.com/2022/10/27/science/mars-meteorites-impacts-seismic.html By  Kenneth Chang , The New York Times.  Excerpt: The exquisitely sensitive seismometer on NASA’s InSight lander dutifully recorded the burst of seismic vibrations and then dispatched the data, a gift of science, to Earth the next day. The InSight scientists were busy celebrating the holidays. When they studied the tremor in detail in early January, it looked different from the more than 1,000 marsquakes that the stationary spacecraft had recorded during its mission to study the insides of the red planet. ...In scientific papers published Thursday, scientists using data from two NASA spacecraft reveal that the seismic event was not the cracking of rocks from the internal stresses of the red planet. Instead, it was shock waves emanating from a space rock hitting Mars. The discovery will help scientists better understand what is inside Mars and serves as a reminder that just like Earth, Mars gets whacked by m

https://webbtelescope.org/contents/media/images/2022/052/01GF423GBQSK6ANC89NTFJW8VM By Webb Space Telescope.  Excerpt: The Pillars of Creation ... is a region where young stars are forming – or have barely burst from their dusty cocoons as they continue to form. Newly formed stars are the scene-stealers in this  Near-Infrared Camera  (NIRCam) image. These are the bright red orbs that sometimes appear with eight diffraction spikes. When knots with sufficient mass form within the pillars, they begin to collapse under their own gravity, slowly heat up, and eventually begin shining brightly. Along the edges of the pillars are wavy lines that look like lava. These are ejections from stars that are still forming. Young stars periodically shoot out supersonic jets that can interact within clouds of material, like these thick pillars of gas and dust. This sometimes also results in bow shocks, which can form wavy patterns like a boat does as it moves through water. These young stars are estimat

https://www.nasa.gov/press-release/nasa-confirms-dart-mission-impact-changed-asteroid-s-motion-in-space By NASA  RELEASE 22-105 .  Excerpt:  Analysis of data obtained over the past two weeks  by NASA’s Double Asteroid Redirection Test (DART) investigation team shows the spacecraft's kinetic impact with its target asteroid, Dimorphos, successfully altered the asteroid’s orbit. This marks humanity’s first time purposely changing the motion of a celestial object and the first full-scale demonstration of asteroid deflection technology. “All of us have a responsibility to protect our home planet. After all, it’s the only one we have,” said NASA Administrator Bill Nelson. “This mission shows that NASA is trying to be ready for whatever the universe throws at us. NASA has proven we are serious as a defender of the planet. This is a watershed moment for planetary defense and all of humanity, demonstrating commitment from NASA's exceptional team and partners from around the world.” Prio

https://gizmodo.com/the-asteroid-that-killed-the-dinosaurs-spawned-a-monste-1849614930 By  Isaac Schultz , Gizmodo.  Excerpt: The impact created fast-moving waves nearly 3 miles high, a new study finds. A team modeling the aftermath of the asteroid impact that doomed the dinosaurs 66 million years ago say that the collision also created a global tsunami that devastated coastlines from North America to New Zealand. The researchers studied ancient sediments from over 100 sites around the world, to see how extreme waves resulting from the impact may have disrupted the geological record. Their work was  presented  at a meeting of the American Geophysical Union in 2018 and is  published  this week in the journal AGU Advances.… 

https://www.nytimes.com/2022/09/30/science/europa-nasa-juno-photos.html By  Kenneth Chang , The New York Times.  Excerpt: Juno, a NASA spacecraft that has been orbiting Jupiter since 2016, zipped within 219 miles of Europa’s surface early on Thursday, speeding by at more than 30,000 miles per hour. Less than 12 hours later, the four images taken during the flyby, the closest observations of the moon since January 2000, were back on Earth. “They’re stunning, actually,” said Candice J. Hansen-Koharcheck, a scientist at the Planetary Science Institute in Tucson, Ariz., who is responsible for the operation of the spacecraft’s primary camera,  JunoCam . ...All four images were available  on Juno’s website .… 

https://www.nasa.gov/press-release/nasa-s-dart-mission-hits-asteroid-in-first-ever-planetary-defense-test NASA RELEASE 22-100.  Excerpt: After 10 months flying in space, NASA’s Double Asteroid Redirection Test (DART) ...successfully impacted its asteroid target on Monday, the agency’s first attempt to move an asteroid in space. Mission control at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, announced the successful impact at 7:14 p.m. EDT. As a part of NASA’s overall  planetary defense  strategy, DART’s impact with the asteroid Dimorphos demonstrates a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered. ...said NASA Administrator Bill Nelson “As NASA studies the cosmos and our home planet, we’re also working to protect that home, and this international collaboration turned science fiction into science fact, demonstrating one way to protect Earth.” DART targeted the asteroid moonlet Dimorphos, a

https://www.nasa.gov/feature/goddard/2022/new-webb-image-captures-clearest-view-of-neptune-s-rings-in-decades By NASA  Laura Betz   (Goddard Space Flight Center, Greenbelt, MD), Hannah Braun and Christine Pulliam (Space Telescope Science Institute, Baltimore, MD).  Excerpt: ...Webb’s extremely stable and precise image quality permits these very faint rings to be detected so close to Neptune. ...Compared to the gas giants, Jupiter and Saturn, Neptune is much richer in elements heavier than hydrogen and helium. This is readily apparent in Neptune’s signature blue appearance in  Hubble Space Telescope images  at visible wavelengths, caused by small amounts of gaseous methane. Webb’s  Near-Infrared Camera  (NIRCam) images objects in the near-infrared range from 0.6 to 5 microns, so Neptune does not appear blue to Webb. In fact, the methane gas so strongly absorbs red and infrared light that the planet is quite dark at these near-infrared wavelengths, except where high-altitude clouds are p

https://eos.org/articles/impact-crater-off-the-african-coast-may-be-linked-to-chicxulub By  Katherine Kornei , Eos/AGU.  Excerpt: In the world of impact craters, Chicxulub is a celebrity: The 180-kilometer-diameter maw, in the Gulf of Mexico, was created by a cataclysmic asteroid impact at the end of the Cretaceous that spelled the demise of most dinosaurs. But researchers have now uncovered another crater off the coast of West Africa that might well be Chicxulub’s cousin. The newly discovered feature, albeit much smaller, is also about 66 million years old. That’s a curious coincidence, and scientists are now wondering whether the two impact structures might be linked. Perhaps Chicxulub and the newly discovered feature—dubbed Nadir crater—formed from the breakup of a parent asteroid or as part of an impact cluster, the team suggested. These results were  published in  Science Advances .… 

https://www.science.org/content/article/nasa-s-unprecedented-asteroid-deflection-mission-more-billiards-space-scientists-say By Zack Savitsky, Science Magazine.  Excerpt: On 26 September, an act of targeted violence will unfold 11 million kilometers from Earth, as a spacecraft about the size of a vending machine smashes into a small asteroid at 6 kilometers per second. Unlike some asteroids that stray worrisomely close to Earth’s orbit, Dimorphos—the 160-meter moon of a larger body—is an innocent bystander, posing no threat to our world. But the looming assault represents humanity’s first-ever field test of a planetary defense mission: NASA’s Double Asteroid Redirection Test, or DART. The hope is that the collision will nudge Dimorphos into a closer orbit around its 780-meter partner, Didymos, shortening its nearly 12-hour orbital period by a few minutes. A successful strike would support the idea that, in the future, similar efforts could deflect threatening asteroids onto safer cours

https://www.science.org/content/article/webb-telescope-takes-its-first-direct-image-exoplanet By Daniel Clery, Science Magazine.  Excerpt: A research team analyzing early data from the James Webb Space Telescope has revealed the instrument’s initial images of a planet beyond our Solar System, a success that closely follows last week’s unveiling of Webb’s first  measurements from the atmosphere of a different exoplanet . The newly imaged young gas giant, seven times the mass of Jupiter, is captured still glowing hot after its formation. The planet’s infrared emissions traveled 350 light-years before the photons were gathered by Webb’s gold-plated mirrors. In a paper  posted today on the arXiv preprint server , the Webb astronomers exhibit several images of the planet, called HIP 65426 b, at a range of wavelengths (shown in insets, above) that have heretofore been invisible to Earthbound telescopes because of our planet’s infrared-blocking atmosphere. ...the high quality of these first i

https://www.nytimes.com/2022/08/28/science/nasa-moon-rocket-launch.html By  Kenneth Chang , The New York Times.  Excerpt: ...astronauts will not actually step on the moon for several years, and by that time, NASA will have spent about $100 billion.... “It’s a future where NASA will land the first woman and the first person of color on the moon,” Bill Nelson, the NASA administrator, said during a news conference this month. “And on these increasingly complex missions, astronauts will live and work in deep space and will develop the science and technology to send the first humans to Mars.” ...Today’s program was named Artemis by NASA leaders during the Trump administration. In Greek mythology, Artemis was the twin sister of Apollo. ...NASA is also hoping to jump-start companies looking to set up a steady business of flying scientific instruments and other payloads to the moon, and to inspire students to enter science and engineering fields.… 

https://eos.org/agu-news/brighter-skies-ahead By Heather Goss , Eos/AGU.  Excerpt: ...An impressive cadre of Sun-targeted missions has recently come online to replace or support an aging fleet of spacecraft, just as solar max is about to set in. ...In February 2020, Solar Orbiter launched from Florida, carrying 10 state-of-the-art instruments to make the closest ever observations of the Sun. Daniele Telloni and colleagues, in “ A New Journey Around (and Around) the Sun , ” describe for us “the groundbreaking observations that Solar Orbiter has made already,” such as the “short-lived, small-scale flickering bright spots, nicknamed ‘campfires,’ in the solar corona.” Not only will this joint European Space Agency–NASA mission shed new light on the unsolved mysteries of the Sun, but also it’s revealing a new side of Venus from its 2020 flyby. ...in our next feature, “ Shake, Rattle, and Probe .” Helioseismology is a burgeoning discipline that allows physicists to better understand the stru

https://www.science.org/content/article/carbon-dioxide-detected-around-alien-world-first-time By Daniel Clery, Science Magazine.  Excerpt: Astronomers have found carbon dioxide (CO 2 ) in the atmosphere of a Saturn-size planet 700 light-years away—the first unambiguous detection of the gas in a planet beyond the Solar System. The discovery, made by the  James Webb Space Telescope , provides clues to how the planet formed. The result also shows just how quickly Webb may identify a spate of other gases, such as methane and ammonia, which could hint at a planet’s potential habitability for life. ...The Webb telescope is sensitive to infrared wavelengths of light that are mostly blocked by Earth’s atmosphere. ...the infrared sensitivity is also critical for researchers.... When an exoplanet’s orbit takes it in front of its star, some of the starlight passes through the planet’s atmosphere and carries fingerprints of its composition. The atmospheric gases absorb specific wavelengths of ligh

https://www.science.org/content/article/all-seeing-telescope-will-snap-exploding-stars-may-spy-hidden-world By Daniel Clery, Science Magazine.  Excerpt: Array of 900 instruments will make movies of heavens, revealing short-lived and fast-changing events. ...Argus aims to achieve its unique vision with hundreds of off-the-shelf telescopes, each just 20 centimeters across and watching a different patch of sky. The final array will match the light-gathering power of a telescope with a single 5-meter mirror, which typically costs hundreds of millions of dollars, but cheap components should keep Argus’s cost below $20 million, Law says. The challenge will come in stitching together the array’s 900 images into a single, seamless movie of the night sky.… 

https://blogs.nasa.gov/webb/2022/08/22/webbs-jupiter-images-showcase-auroras-hazes/ By Alise Fisher , NASA Webb Space Telescope.  Excerpt: ...NASA’s James Webb Space Telescope has captured new images of [Jupiter].  ...“We hadn’t really expected it to be this good, to be honest,” said planetary astronomer Imke de Pater, professor emerita of the University of California, Berkeley. ...“It’s really remarkable that we can see details on Jupiter together with its rings, tiny satellites, and even galaxies in one image,” she said. The two images come from the observatory’s Near-Infrared Camera (NIRCam), which has three specialized infrared filters that showcase details of the planet. Since infrared light is invisible to the human eye, the light has been mapped onto the visible spectrum. Generally, the longest wavelengths appear redder and the shortest wavelengths are shown as more blue. Scientists collaborated with citizen scientist Judy Schmidt to translate the Webb data into images. In the

https://www.science.org/content/article/stowaways-nasa-s-massive-moon-rocket-promise-big-science-small-packages By Erik Hand, Science Magazine.  Excerpt: CubeSats packed on Artemis 1 will target lunar ice—if their batteries don’t fail them. When NASA’s most powerful rocket ever attempts its first flight this month, its highest profile payload will be three instrumented mannequins, setting off on a 42-day journey beyond the Moon and back. They are stand-ins for the astronauts that the 98-meter-tall rocket, known as the Space Launch System (SLS), is supposed to carry to the Moon as soon as 2025, as part of NASA’s Artemis program. But there will be other voyagers along for the ride when the SLS lifts off on 29 August: 10 CubeSats, satellites no bigger than a small briefcase, to probe the Moon, asteroids, and the radiation environment of deep space. ...Several SLS CubeSats will focus on lunar ice, which has intrigued researchers ever since NASA’s Lunar Prospector discovered a signal sugges

https://www.science.org/content/article/nearby-star-midlife-crisis-suggests-our-own-sun-may-lose-its-spots-again-decades By Zack Savitsky, Science Magazine.  Excerpt: Long magnetic lull on star mimics the Maunder Minimum, when the Sun’s spots largely disappeared 400 years ago. Soon after European astronomers developed the first telescopes at the start of the 17th century, they observed dark spots speckling the Sun’s surface. They also handed their modern successors a mystery. From about 1645 to 1715, the spots, now known to be indicators of solar activity, all but disappeared. Gathering sunspot counts and other historical observations, astronomer John Eddy concluded nearly 50 years ago that the Sun had essentially taken a 70-year nap, which he called  the Maunder Minimum  after an astronomer couple who had previously studied it. Now, it appears the Sun is not the only star that takes long naps. By building a decades-long record of observations of a few dozen stars at specific wavelengt

https://www.science.org/content/article/webb-telescope-reveals-unpredicted-bounty-bright-galaxies-early-universe By Daniel Clery, Science Magazine.  Excerpt: Star formation after the big bang appears much faster than models had forecast. The James Webb Space Telescope has only been watching the sky for a few weeks, and it has already delivered a startling finding: tens, hundreds, maybe even 1000 times more bright galaxies in the early universe than astronomers anticipated. “No one was expecting anything like this,” says Michael Boylan-Kolchin of the University of Texas, Austin. “Galaxies are exploding out of the woodwork,” says Rachel Somerville of the Flatiron Institute. Galaxy formation models may now need a revision, as current ones hold that gas clouds should be far slower to coalesce into stars and galaxies than is suggested by Webb’s galaxy-rich images of the early universe, less than 500 million years after the big bang. “This is way outside the box of what models were predictin

https://www.nasa.gov/feature/goddard/2022/webb-captures-stellar-gymnastics-in-the-cartwheel-galaxy By  NASA, ESA, CSA, STScI .  Excerpt: NASA’s James Webb Space Telescope has peered into the chaos of the Cartwheel Galaxy, revealing new details about star formation and the galaxy’s central black hole. Webb’s powerful infrared gaze produced this detailed image of the Cartwheel and two smaller companion galaxies against a backdrop of many other galaxies. ...The Cartwheel Galaxy, located about 500 million light-years away in the Sculptor constellation, is a rare sight. Its appearance, much like that of the wheel of a wagon, is the result of an intense event – a high-speed collision between a large spiral galaxy and a smaller galaxy not visible in this image. ...The collision most notably affected the galaxy’s shape and structure. The Cartwheel Galaxy sports two rings — a bright inner ring and a surrounding, colorful ring. These two rings expand outwards from the center of the collision, li

https://eos.org/research-spotlights/a-unified-atmospheric-model-for-uranus-and-neptune By  Morgan Rehnberg , Eos/AGU.  Excerpt:  In a new model, three substantial atmospheric layers appear consistent between the ice giants.  The ice giants, Uranus and Neptune, are the least understood planets in the solar system. They remain the only worlds that an orbital spacecraft has not visited. Our limited understanding of them derives largely from the flyby of NASA’s  Voyager 2  probe and subsequent observations with the  Hubble Space Telescope . Yet the ice giants may be most representative of the extrasolar planets in our local vicinity. Why these planets appear so different in color despite having very similar physical properties, including vertical temperature profile and atmospheric composition, is a mystery. Past investigations have attributed Neptune’s deeper blue largely to excess absorption in the red and near infrared from atmospheric methane. ... Irwin et al .  attempt to fill this ga

https://webbtelescope.org/news/news-releases By NASA, ESA, Canadian Space Agency.  Excerpt: The first images and spectroscopic data from NASA’s James Webb Space Telescope have revealed unprecedented and detailed views of the universe. Webb’s first images and spectra, including downloadable files, can be found at  https://webbtelescope.org/news/first-images .… See zoomable image of Webb's First Deep Field (very early galaxies); Deepest Image of Universe ; Spectrum of an exoplanet ; Southern Ring Nebula (dying star); Stephan’s Quintet (merging galaxies); star-forming region NGC 3324  in the Carina Nebula; and Science Magazine article  Webb telescope wows with first images .

https://www.nytimes.com/2022/07/02/science/webb-telescope-exoplanets-atmosphere.html Source:     Carl Zimmer , The New York Times Excerpt:  The first question astronomers want to answer about exoplanets: Do they have atmospheres friendly to life? ... Identifying an atmosphere in another solar system would be remarkable enough. But there is even a chance — albeit tiny — that one of these atmospheres will offer what is known as a biosignature: a signal of life itself. ... Scientists are still debating what a reliable biosignature would be. Earth’s atmosphere is unique in our solar system in that it contains a lot of oxygen, largely the product of plants and algae. But oxygen can also be produced without life’s help, when water molecules in the air are split. Methane, likewise, can be released by living microbes but also by volcanoes.

https://eos.org/articles/zhurong-rover-spots-evidence-of-recent-liquid-water-on-mars ]  By Katherine Kornei , Eos/AGU.  Excerpt: Mars is hardly a verdant world today, yet evidence abounds that liquid water  once flowed over the Red Planet . Now, the latest rover to arrive on Mars’s surface—Zhurong, part of China’s  Tianwen-1 mission —has spotted hydrated minerals that point to liquid water persisting well into the Red Planet’s most recent geologic period. These results,  published in  Science Advances , contribute to our understanding of when liquid water flowed on Mars, the research team has suggested.…

https://eos.org/articles/why-did-sunspots-disappear-for-70-years-nearby-star-holds-clues By Kimberly M. S. Cartier , Eos/AGU. Excerpt: Every 11 years, the number of spots dotting the surface of the Sun increases and decreases like clockwork. Astronomers have been tracking the 11-year sunspot cycle for more than 400 years, using it to better understand the chaotic magnetic field the Sun puts out. (The current solar cycle, number 25, started in 2019.) The timing of the solar cycle is remarkably consistent: Sunspot numbers rise and fall, rise and fall…except for that time that they disappeared and weren’t seen again for 70 years. That period of time, from 1645 to 1715, is known as the  Maunder Minimum , named after 19th century British astronomers Edward and Annie Maunder. Astronomers still don’t understand why the Sun ceased making sunspots for 70 years, but a new analysis of more than 5 decades of measurements of nearby stars has identified one that might be undergoing its own Maunder-l

https://news.berkeley.edu/2022/06/10/astronomers-may-have-detected-a-dark-free-floating-black-hole/ By Robert Sanders , UC Berkeley News.  Excerpt: If, as astronomers believe, the death of large stars leave behind black holes, there should be hundreds of millions of them scattered throughout the Milky Way galaxy. The problem is, isolated black holes are invisible. Now, a team led by University of California, Berkeley, astronomers has for the first time discovered what may be a free-floating black hole by observing the brightening of a more distant star as its light was distorted by the object’s strong gravitational field — so-called gravitational microlensing. The team, led by graduate student Casey Lam and  Jessica Lu , a UC Berkeley associate professor of astronomy, estimates that the mass of the invisible compact object is between 1.6 and 4.4 times that of the sun. Because astronomers think that the leftover remnant of a dead star must be heavier than 2.2 solar masses in order to co