AC7C. Stay Current—Planet-Star Systems

Asteroid visualization (YouTube) – an animation of the solar system showing asteroid discoveries starting in 1980. Earth Crossers are Red. Earth Approachers (Perihelion less than 1.3AU) are Yellow. All Others are Green.

Articles from 2021–present

2024-06-12. WHAT MARTIAN GULLIES MEAN FOR WATER ON MARS. By EMILY LAKDAWALLA , Sky & Telescope. Excerpt: Martian gullies have been the center of a debate about whether Mars ever has flowing water. Now, a comprehensive study examines the question. Lots of Mars’s hillslopes have gullies, steep ravines that grow when we’re not looking. They look so much like Earth’s own gullies, formed when water and debris carve into steep slopes, that it’s easy to think that water must be involved on Mars, too. But physics says water shouldn’t ever be liquid anywhere on the Martian surface today. Many scientists therefore think gully formation must be triggered by some kind of dry process, involving ice (either water ice or carbon dioxide ice) that sublimates directly from solid to gas. In a new study, published in the August 2024 issue of Icarus, Axel Noblet (University of Western Ontario, Canada) and colleagues amass data on nearly 8,000 gullied slopes and come up with an answer to the “wet or dry” question: It’s both, and it depends. …The correlation with some ground ice strongly suggests that gullies have formed in places at the edges of ice deposits. That suggests they formed during a transition from a wetter period, favoring the formation of ground ice, to the present-day, dry period. …But what about the gullies that have been seen to expand on Mars today,…. And what about the gullies near the poles? …A plausible answer to these questions involves carbon dioxide. While dry ice doesn’t expand as it freezes, like water does, condensation of dry ice can fill all the pores in the ground and glue particles together. If that ice suddenly goes away — say, when sunrise on a spring day lights up the ground for the first time in months — the sudden withdrawal of support can collapse the ground, and the rush of expanding gas can “fluidizing” the soil, reducing friction and encouraging flow even though no liquid is present…. Full article at

2024-06-07. A Splashy Meteorite Was Forged in Multiple Collisions. By Damond Benningfield, Eos/AGU. Excerpt: The Winchcombe meteorite splashed into headlines on 28 February 2021, when it streaked above Gloucestershire, England, and broke apart in the atmosphere. Its largest chunk hit a driveway in the village of Winchcombe and splattered into thousands of pieces. …Analysis of the meteorite and video of its descent revealed that its parent meteoroid was probably 20–30 centimeters in diameter when it hit the atmosphere, with a mass of about 13 kilograms. …The research team’s analyses revealed that the meteorite contains eight rock types, all of which show evidence of having been altered by water. …In addition to revealing the asteroid’s history, the lab work also supported the suggestion that CM and other carbonaceous chondrites supplied young Earth with water and organic compounds…. Full article at

2024-05-16. Distant Stars Spotlight Mini Moons in Saturn’s Rings. By Katherine Kornei, Eos/AGU. Excerpt: Using data from the Cassini spacecraft, researchers studying one of the rings recently uncovered gaps just a few tens of meters wide that they believe surround unseen mini moonlets. …In addition to capturing more than 450,000 images of the Saturnian system, the spacecraft inadvertently tracked distant stars poking through Saturn’s rings. …The researchers spotted dozens of places in Saturn’s C ring—one of its innermost rings—that appeared to be 100% transparent. …Their elongated geometry was a tip-off to their potential identity—similarly shaped structures, albeit much larger, have been spotted in the outer regions of Saturn’s A ring. Known as propellers [resembling airplane propellers], those features are big enough to show up in Cassini imagery rather than just occultation data, Jerousek said. …Scientists believe that propellers exist because of unseen moonlets measuring, at most, several hundred meters in diameter…. Full article at

2024-05-06. Hellish Venus may have lost its water quickly. By JONATHAN O’CALLAGHAN, Science. Excerpt: With surface temperatures hot enough to melt lead, Venus today is a veritable hellhole, despite being similar in size to Earth and orbiting in the habitable zone of the Sun. Yet studies suggest the planet may have once hosted oceans and even conditions suitable for life. Explaining how all that water disappeared has been a problem. A study published today in Nature offers a solution, identifying a new water-loss mechanism operating high in Venus’s atmosphere that could have doubled the rate of water loss. Speedier drying could have allowed oceans to exist until later in Venus’s history—implying the planet might have been habitable for longer. …At 96% carbon dioxide, its atmosphere traps so much heat that surface temperatures reach more than 450°C. Yet spacecraft and telescopes have seen faint hints of water vapor in the atmosphere, and in the late 1970s, NASA’s Pioneer Venus orbiter detected a sign of long-vanished oceans: an enrichment of heavy hydrogen, deuterium. …The authors of the new study say they have identified new water-loss chemistry that can resolve the problem. …some 150 kilometers above the surface, sunlight would not only split water vapor but also carbon dioxide, creating hydrogen and carbon monoxide that would combine into an unstable ion called HCO+ …[that] would break apart to shed excess energy. …“The hydrogen uses the carbon monoxide molecule as a launchpad to escape to space,” explaining how the last “dregs” of venusian water could have been lost even after hydrodynamic loss ceased. …Venus may have held onto its oceans until much more recently, perhaps 2 billion to 3 billion years ago…. Full article at

2024-04-23. A hunk of space junk crashed through his roof in Florida. Who should pay to fix it? By Bill Chappell, NPR. Excerpt: Alejandro Otero was out of town on vacation last month when his son called from their house in Naples, Fla., to tell him …he heard an extremely loud crash — and realized it came from inside the house. …the object wasn’t a meteorite. It was cylindrical, and while one end was melted by the heat of reentry, the other had a smooth round shape with a circular indentation. …[It was] a large battery pallet from the International Space Station that NASA released for an uncontrolled reentry, three years ago. …”The location of the reentry was predicted by the 18th Space Defense Squadron to be in the Gulf of Mexico,”. …”We are in the process of sending NASA our claim which will include the insurance and non-insurance damages,” he says, adding that his lawyer has been in touch with NASA’s legal counsel. …”It will depend on whose module of the space station that came from,” said Sundahl, who is the director of the Global Space Law Center at Cleveland State University. “We have an international convention on liability for damage caused by outer space objects …from 1972. …But, Sundahl added, if the object in question turns out to be part of a U.S. module, “then the international law no longer applies. It becomes a domestic legal issue, and a homeowner would have to bring a tort action against the federal government.”…. Full article at

2024-04-17. Where did Earth’s oddball ‘quasi-moon’ come from? Scientists pinpoint famed lunar crater. By DANIEL CLERY, Science. Excerpt: Astronomers suspect an unusual near-Earth rocky object is not a typical escapee from the Solar System’s asteroid belt, but is instead a chunk of the Moon blasted into space eons ago by a spectacular impact. Now, a team of researchers has modeled what sort of lunar impact could have ejected such a gobbet of Moon and deposit it in a stable, nearby orbit. Surprisingly, only one strong candidate emerged: the asteroid strike that created the famous Giordano Bruno crater, the youngest large crater on the Moon, the group reports today in Nature Astronomy. …The odd asteroid, known as 469219 Kamo‘oalewa, was discovered in 2016 …measures between 40 and 100 meters across and rotates particularly fast—once every 28 minutes. It follows an elliptical orbit around the Sun that moves in sync with Earth, giving the impression that the asteroid orbits Earth, even though it is outside the planet’s gravitational influence. The asteroid’s curious orbit and small size led to it being chosen as the first target for China’s sample return mission Tianwen-2, set for launch in 2025. …Interest in the asteroid heightened in 2021, when studies by the Large Binocular Telescope Observatory in Arizona first suggested its composition more closely resembles a Moon rock than a typical asteroid. The spectrum of the light reflected off Kamo‘oalewa revealed silicates more typical of a lunar sample…. See article at

2024-04-16. Giant planets ran amok soon after Solar System’s birth. By PAUL VOOSEN, Science. Excerpt: In its youth, the Solar System underwent a momentous upheaval: Gravitational tugs between the giant planets threw them off track, causing Jupiter’s orbit to jump closer to the Sun, while Saturn, Uranus, and Neptune were flung outward. The gravity of the rampaging giants scattered Pluto and other icy bodies to the Kuiper belt, shepherded the asteroid belt into its current location, and sent countless bodies crashing into the inner Solar System. For many years, researchers believed this “giant planet instability” occurred 600 million years after the Solar System’s birth 4.57 billion years ago, based on the ages of impact craters mapped on the Moon. Recently, evidence has mounted that it occurred much earlier. And now, some researchers are homing in on a more precise date, just 60 million years after the Solar System’s formation, based on an analysis of rare meteorites derived from an ancient asteroid family, published today in Science. Other recent work seems to corroborate the date: the impact history captured in common meteorites, the formation history of the icy dwarf planet Haumea, and the earliest known mineral crystals found in Moon rocks retrieved by Apollo astronauts. “When you put it all together, that’s a lot of evidence for impacts all right around 60 million years,” says Steven Desch, an astrophysicist at Arizona State University…. See article at

2024-02-15. What Does a Solar Eclipse on Mars Look Like? New, Breathtaking Images, Caught by NASA’s Perseverance Rover, Give Us an Idea. [] By Carlyn Kranking, Smithsonian Magazine. Excerpt: The robot recently observed each of the Red Planet’s moons passing across the sun in the Martian sky [see photo in this article].

2024-01-19. JAPAN’S “SNIPER” MISSION PINPOINTS LANDING ON THE MOON. [] By DAVID DICKINSON, Sky & Telescope. Excerpt: Today, the Japanese Aerospace Exploration Agency (JAXA Smart Lander for Investigating the Moon (SLIM) spacecraft pitched over in its lunar orbit, and began its long descent to the Moon’s surface. Touchdown occurred at 10:20 a.m. EST / 15:20 UT; NASA’s Deep Space Network in Madrid picked up the lander’s signal shortly afterward, but problems have ensued. …SLIM was designed to test the innovative “smart eyes” landing technology, which involves image-matching to aid navigation. The mission was also designed to demonstrate a pinpoint landing, that is, within 100 meters of the target, on a 6- to 8-degree slope. SLIM has a Multi-Band Camera camera on board and, if it is able to, it will deploy two baseball-size rovers on the lunar surface named Lunar Exploration Vehicle 1 and 2. These will hop and roll along the lunar surface, imaging with cameras of their own. If the solar cells are able to charge, SLIM could last about 11 days on the lunar surface. The Sun will set over the landing site on January 30th….

2024-01-10. Scientists Investigate How Heat Rises Through Europa’s Ocean. [] By Rebecca Owen, Eos/AGU. Excerpt: Europa, one of Jupiter’s many moons, may be capable of supporting life because its icy surface likely obscures a deep, salty ocean. Europa’s ocean is also in direct contact with its mantle rocks, and interactions between rock, water, and ice could provide energy to sustain life. Lemasquerier et al. examined the way heating from Europa’s mantle could drive ocean circulation under the icy crust. The researchers modeled Europa’s ocean to further understand how heating patterns from deep inside the moon may affect the thickness of its icy surface. …Mantle heat …comes in two forms. Radiogenic heating is caused by the decay of radioactive materials in the mantle, and tidal heating is caused by the deformation Europa undergoes as it orbits Jupiter and experiences its strong gravitational pull. Tidal heating is uneven; it’s higher at Europa’s poles and lower at the points of the moon that are opposite and facing Jupiter. …if tidal heating is dominant in the mantle, …affecting ice thickness and leaving it thinnest at the poles. However, if radiogenic heating is the dominant type of heating in the mantle, then the ocean would have a relatively small impact on ice thickness. The 2024 Europa Clipper mission could help confirm these model findings….

2023-12-14. Poison Gas Hints at Potential for Life on an Ocean Moon of Saturn. [] By Kenneth Chang, The New York Times. Excerpt: Scientists have detected a poison among the spray of molecules emanating from a small moon of Saturn. That adds to existing intrigue about the possibility of life there. The poison is hydrogen cyanide, a colorless gas that is deadly to many Earth creatures. But it could have played a key role in chemical reactions that created the ingredients that set the stage for the advent of life. …Mr. Peter and his collaborators, Tom Nordheim and Kevin Hand of NASA’s Jet Propulsion Laboratory in California, reported their findings in a paper published on Thursday in the journal Nature Astronomy….

2023-11-08. LUCY MISSION FLIES BY ASTEROID DINKINESH, FINDS BINARY MOON. [] By EMILY LAKDAWALLA, Sky & Telescope. Excerpt: On November 1st, the Lucy mission zipped past the tiny asteroid 152830 Dinkinesh and discovered that it was actually a binary. …While the probe caught a view of the Dinkinesh’s small satellite in the one of the first images of the flyby, the mission turned as it flew by and captured another view from a different angle. That new perspective revealed that the little asteroidal moon is actually a contact binary, meaning it’s made of two objects in contact with one another. This is the first contact binary asteroid moon discovered. Read more details on NASA’s website….

2023-11-06. The Moon Is Even Older Than Scientists Thought. [] By Matt Hrodey, Eos/AGU. Excerpt: Thanks to one of the slowest-ticking clocks in the universe, scientists have determined the Moon is about 40 million years older than previously thought. That means the Earth was a young 100 million years old when an object about the size of Mars slammed into it, slinging magma out into Earth’s orbit. …As the Moon’s mantle cooled, it formed tiny zircon crystals, …sometimes contain other elements, such as uranium …can be used to date when the crystal originally formed, going back billions of years, if necessary. …the researchers obtained lunar dust collected by Apollo 17 in 1972 and analyzed the tiny zircon crystals and uranium contained inside. …Radioactive isotopes of uranium (such as Uranium-238) contain unstable combinations of protons and neutrons in their nuclei and will eventually break down into lead… Scientists determined the age of the Moon by counting the proportion of lead remaining in a lunar zircon; they sharpened parts of the crystal to fine points and evaporated atoms from the tip with ultraviolet lasers. Once released, the atoms passed through a mass spectrometer that could detect their mass and thus their identity. Based on the balance they found, the researchers estimated the Moon’s age at 4.46 billion years old….

2023-11-02. Five Martian Mysteries That Have Scientists Scratching Their Heads. [] By Matthew R. Francis, Eos/AGU. Excerpt: .1. Why Is the Southern Hemisphere So Bulgy? 2. Where Has All the Water Gone? 3. Why Is Mars an Ice Ball? 4. Is There Methane? 5. How Much Does the Planet Wobble? ….

2023-10-25. Mars has a surprise layer of molten rock inside. [] By Alexandra Witze, Nature. Excerpt: A meteorite that slammed into Mars in September 2021 has rewritten what scientists know about the planet’s interior. By analysing the seismic energy that vibrated through the planet after the impact, researchers have discovered a layer of molten rock that envelops Mars’s liquid-metal core. The finding, reported today in two papers in Nature1,2, means that the Martian core is smaller than previously thought. It also resolves some lingering questions about how the red planet formed and evolved over billions of years. The discovery comes from NASA’s InSight mission, which landed a craft with a seismometer on Mars’s surface. Between 2018 and 2022, that instrument detected hundreds of ‘marsquakes’ shaking the planet. Seismic waves produced by quakes or impacts can slow down or speed up depending on what types of material they are travelling through, so seismologists can measure the waves’ passage to deduce what the interior of a planet looks like. …the September 2021 meteorite impact “unlocked everything”, says Henri Samuel, a geophysicist at the Institute of Earth Physics of Paris and lead author of one of today’s papers1. The meteorite struck the planet on the side opposite to where InSight was located. That’s much more distant than the marsquakes that InSight had previously studied, and allowed the probe to detect seismic energy travelling all the way through the Martian core4…. For

2023-10-19. Webb telescope discovers intense jet stream in Jupiter’s atmosphere. [] By Robert Sanders, UC Berkeley News. Excerpt: NASA’s James Webb Space Telescope has discovered a fast-moving jet stream in Jupiter’s atmosphere that is blowing twice as fast as the visible cloud layers below it, creating wind shears that far exceed anything seen on Earth. The high-speed jet stream, which is traveling at 320 miles per hour (515 kilometers per hour) and is more than 3,000 miles (4,800 kilometers) wide, sits over Jupiter’s equator, 15 to 30 miles (25 to 50 kilometers) above the main cloud deck familiar from optical photos. …winds in the visible cloud layer blow at about 180 mph (250 km/hour). This means that for every kilometer above these visible clouds, the wind speed increases by 7 to 10 kilometers per hour, according to Ricardo Hueso, lead author of a paper describing the findings published today in the journal Nature Astronomy….

2023-10-13. NASA launches spacecraft to a mysterious metal-rich asteroid. [] By MICHAEL GRESHKO, Science. Excerpt: …a $1.2 billion NASA mission to Psyche launched today. …Psyche will be the first to rendezvous with an “M-type” asteroid: a group of unusually reflective and dense asteroids. For decades, scientists have wondered whether Psyche could be the denuded metal core of a larger protoplanet. …Once the spacecraft arrives at Psyche in 2029, it will spend more than 2 years in orbit….

2023-09-25. Oceans of Opportunity. [] By Caryl-Sue Micalizio, Eos/AGU. Our solar system’s ocean worlds—planets and moons covered in ice-crusted oceans—are weird, wonderful, and ripe for exploration. [Here are a series of articles] Uranus: A Time to Boldly Go by Kimberly Cartier; Marine Science Goes to Space by Damond Benningfield on how ocean worlds are redefining what constitutes a habitable zone and how missions in development, like JUICE and Europa Clipper, are relying on terrestrial deep-sea scientific advances to look for oceanic activity that’s out of this world. …older missions are still contributing to the discourse, as archival Cassini data helped scientists identify phosphorus—the rarest element necessary for life as we know it—on Enceladus. …Erik Klemetti explores Cryovolcanism’s Song of Ice and Fire….

2023-09-24. NASA delivers bounty of asteroid samples to Earth. [] By PAUL VOOSEN, Science. Excerpt: …today, after detaching from NASA’s OSIRIS-REx spacecraft, a capsule carrying asteroid samples descended gently by parachute before touching down in the Utah desert. The cupful of pebbles and grit it delivered—the culmination of 7 years of effort and $1 billion of expense—is only the third sample of an asteroid ever returned to Earth, and it’s the largest haul of extraterrestrial material NASA has collected since the Apollo Moon missions. …In 2020, Japan’s Hayabusa2 spacecraft returned some 5 grams of material from Ryugu, another carbon-rich, near-Earth asteroid, which was thought to be relatively dry. Instead, it appears to have been fully altered by water. “We were all terribly wrong about Ryugu,” says Edward Young, a cosmochemist at the University of California, Los Angeles. …If they are wrong about Bennu, it will be the opposite mistake. Remote observations suggest some 10% of Bennu’s mass is made up of water locked in clays. …As it orbited Bennu, OSIRIS-REx glimpsed another sign of a watery past: meter-long veins of carbonate, a mineral that precipitates out of solution. The water may have flowed on Bennu’s parent body, which likely formed beyond Jupiter’s orbit, at the Solar System’s very beginning 4.56 billion years ago. See also NASA OSIRIS-Rex overview and science briefing videos….

2023-09-21. The distribution of CO2 on Europa indicates an internal source of carbon. [] By SAMANTHA K. TRUMBO AND MICHAEL E. BROWN, Science. Excerpt: [Editor’s summary:] Europa, an icy moon of Jupiter, has a subsurface ocean beneath a crust of water ice. Solid carbon dioxide (CO2) has previously been observed on its surface, but the source was unknown. Two teams analyzed infrared spectroscopy of Europa from the James Webb Space Telescope to investigate the CO2 source. Trumbo and Brown found that the CO2 is concentrated in a region with geology that indicates transport of material to the surface from within the moon, and they discuss the implications for the composition of Europa’s internal ocean. Villanueva et al. also identified an internal origin of the CO2 and measured its 12C/13C isotope ratio. They searched for plumes of volatile material breaching the surface but found a lower activity than earlier observations. Together, these studies demonstrate that there is a source of carbon within Europa, probably in its ocean. —Keith T. Smith….

2023-08-09. Ancient mud cracks on Mars point to conditions favorable for life. [] By Phil Jacobs, Science. Excerpt: …the discovery of distinctive mud cracks on the planet’s surface suggest ancient Mars cycled through sustained wet and dry seasons for millions of years. Not only would the climate have been habitable, scientists say, but the cycling might have also given the basic chemistry of life a boost. The discovery, reported today in Nature, is compelling evidence for an Earth-like climate on early Mars…. the Curiosity rover has discovered patterns of hexagon-shaped cracks in ancient rocks that add to the evidence for a sustained warm climate. They resemble patterns found on Earth in places like Death Valley, where they only form after years of wet-dry cycling….

2023-07-26. View the Thin Crescent of Venus. [] By Bob King, Sky & Telescope. Excerpt: With Venus approaching inferior conjunction in August, here’s a foolproof way to follow its thinning crescent as the planet transitions from Evening Star to Morning Star. …Venus currently shines about 25° east of the Sun and sets about 45 minutes after sundown. On August 13th the two bodies will be in conjunction and rise and set together. For about a week before and after that date, Venus will be difficult-to-impossible to see with the naked eye because of interference from solar glare but remain visible in a telescope if you know exactly where to look. The orbit of Venus is tipped 3.4° relative to the plane of the ecliptic [Earth’s orbit plane]. At inferior conjunction, when the two planets are closest, Venus can pass up to 8.4° north or south of the Sun. If Venus lies at or close to either one of its nodes — the two points where it intersects the plane of Earth’s orbit — we’ll see it transit across the Sun’s face. That last happened in June 2012 and will happen again in December 2117. During the present apparition, Venus will pass 7.7° south of the Sun’s center, close to its maximum distance, making it possible to safely follow the planet up to and beyond solar conjunction. This only happens occasionally. For instance, during the June 2020 conjunction, Venus sat just 0.5° north of the Sun — much too close to safely view. At its last conjunction in January 2022, the Sun and planet were less than 5° apart….

2023-07-12. Perseverance Finds Complex Organics (Not Life) On Mars. [] By Colin Stuart, Sky & Telescope Magazine. Excerpt: Planetary scientists analyzing data from NASA’s Perseverance rover have found signs of organic molecules on Mars, hinting that the planet had a more complex geochemical cycle in the past than previously thought. If true, it shows that the building blocks of life have been present on the Red Planet for around billions of years. These new findings, published in Nature, come from examining the floor of Jezero Crater, a 45-kilometer- (28-mile-) wide impact basin just north of the Martian equator. NASA picked it as Perseverance’s landing site due to geological signs that an ancient river flooded into the crater some 2.5 billion years ago….

2023-06-14. Detection of phosphates originating from Enceladus’s ocean. [] By Frank PostbergYasuhito SekineFabian KlennerChristopher R. GleinZenghui ZouBernd AbelKento FuruyaJon K. HillierNozair KhawajaSascha KempfLenz NoelleTakuya SaitoJuergen SchmidtTakazo ShibuyaRalf Srama & Shuya Tan, Nature. Excerpt: Saturn’s moon Enceladus harbours a global ice-covered water ocean2,3. The Cassini spacecraft investigated the composition of the ocean by analysis of material ejected into space by the moon’s cryovolcanic plume4,5,6,7,8,9. The analysis of salt-rich ice grains by Cassini’s Cosmic Dust Analyzer10 enabled inference of major solutes in the ocean water (Na+, K+, Cl, HCO3, CO32–)…. Here we present Cassini’s Cosmic Dust Analyzer mass spectra of ice grains emitted by Enceladus that show the presence of sodium phosphates. …of the six elements—C, H, N, O, P and S—that are generally considered to be critical ingredients for life …, phosphorus is cosmochemically the least abundant and has not previously been detected at any of the ocean-bearing moons in the Solar System. However, the results presented here demonstrate that Enceladus instead has a high availability of dissolved P, which is thus extremely unlikely to be a limiting factor in the survival of putative life on Enceladus—and perhaps also on other ocean worlds that reside beyond the CO2 snowline in the Solar System (that is, the distance from the Sun beyond which CO2 is in a solid (icy) state and is available as a planetary building material)…. See also articles in The Washington Post and The New York Times.

2023-06-09. Saturn’s Shiny Rings May Be Pretty Young. [] By Kimberly M. S. Cartier, Eos/AGU. Excerpt: …Data from NASA’s Cassini mission showed how fast dust has been pelting the Saturnian system, revealing that for the rings to have remained as shiny and dust-free as they are, they can be only as much as 400 million years old, much younger than the planet itself. …The Sun and its planets formed around 4.5 billion years ago, and many of the planets’ moons, including ours, followed not long after. Astronomers initially thought that Saturn’s rings formed during that early dynamical period, when large collisions were common. …The rings’ orbits and compositions support the idea they are old. …Measurements of the rainfall rate and the total mass of the rings from NASA’s Cassini spacecraft, which orbited Saturn for 13 years, suggested that the rings must be far younger than the planet; otherwise, they would have disappeared already. Cassini also revealed that the rings are fairly shiny, having accumulated only a small amount of cosmic dust—tiny silicate particles that come from the far reaches of the solar system or beyond….

2023-05-30. Giant plume spotted erupting from moon of Saturn might contain ingredients for life. [] By Ron Cowen, Science. Excerpt: NASA’s JWST space telescope has observed a 10,000-kilometer-long plume of water vapor jetting into space from Saturn’s moon Enceladus—the largest spray ever detected from the icy world, which is just one-seventh the diameter of Earth’s Moon. …Planetary scientists view Enceladus as a prime target in the search for extraterrestrial life because beneath its icy crust the moon houses a salty ocean—a good medium for the ingredients of life to mix. …Researchers describe the results today in a NASA press release and in a paper accepted at Nature Astronomy. …NASA’s Cassini mission, which in 2005 discovered the plumes on Enceladus  …flew through them seven times during its 13-year mission, discovering organic molecules such as methane and formaldehyde, and hydrogen, a potential energy source for microbes….

2023-05-12. With 62 Newly Discovered Moons, Saturn Knocks Jupiter Off Its Pedestal. [] By Jonathan O’Callaghan, The New York Times. Excerpt: This month, the International Astronomical Union is set to recognize 62 additional moons of Saturn based on a batch of objects discovered by astronomers. The small objects will give Saturn 145 moons — eclipsing Jupiter’s total of 95. …The growing number of moons also highlights potential debates over what constitutes a moon. “The simple definition of a moon is that it’s an object that orbits a planet,” Dr. Sheppard said. An object’s size, for the moment, doesn’t matter. …In March, Dr. Sheppard was also responsible for finding 12 new moons of Jupiter, which took it temporarily above Saturn in the scuffle to be the biggest hoarder of moons. That record was short-lived, it seems….

2023-05-06. Four of Uranus’s Moons Might Contain Briny Oceans. [] By Emily Lakdawala, Sky & Telescope. Excerpt: A new paper re-analyzing Voyager observations suggests that four of Uranus’ five icy satellites also host oceans: Ariel, Umbriel, Titania, and Oberon. (Only small Miranda, intermediate in size between Saturn’s Mimas and Enceladus, appears not to.) The oceans are desperately thin: less than 30 kilometers (20 miles) thick inside Ariel and Umbriel (both of which are about 1,000 kilometers across, similar in size to Saturn’s Tethys and Dione), and less than 50 kilometers thick within Titania and Oberon (which are larger at about 1,500 kilometers, similar to Saturn’s Rhea and Iapetus). If the oceans exist, they would be left over from much larger liquid layers that formed when the moons first formed. …They’d be extremely briny, hyper-concentrated with whatever dissolved materials helped to lower the temperature at which water would otherwise freeze. There are two candidate materials: salt and ammonia….

2023-04-25. The Smallest Moon of Mars May Not Be What It Seemed. [] By Jonathan O’Callaghan, The New York Times. Excerpt: Deimos, the smaller of the two moons of Mars, might be a chip off the old block — quite literally. That’s the conclusion drawn by scientists in the United Arab Emirates, whose Hope orbiter — also called the Emirates Mars Mission and the country’s first interplanetary spacecraft — just snapped the best views of Deimos ever taken by human spacecraft. …Mars has two irregularly shaped moons, and neither is mighty. Phobos, the larger of the two, is about 17 miles in diameter at its widest, and orbits closer to the red planet at an altitude of about 3,700 miles. Deimos is just nine miles across on its longest side, and completes an orbit of Mars every 30 hours at an altitude of 15,000 miles. The moons’ small size and quirky dimensions led to suggestions that they may be asteroids captured by Mars long ago. Not so, say researchers analyzing data recorded by Hope, which entered orbit around Mars in February 2021. The mission, primarily intended to study the Martian atmosphere, has spent 2023 in an extended phase performing multiple flybys of Deimos. …Hope’s three scientific instruments were able to probe the composition of Deimos. They found it was more similar to Mars, namely in the amount of carbon and organics present, than to D-type asteroids, the class of asteroids previously suggested as its origin….

2023-04-07. Does Earth Have a New Quasi-moon? [] By David Chandler, Sky & Telescope Magazine. Excerpt: Recently discovered asteroid 2023 FW13 has created a bit of a stir among asteroid watchers. It turns out to be on an orbit that is not only in a 1:1 resonance with the Earth, but follows a path that actually circles Earth — albeit on an orbit that is so eccentric that it sweeps out halfway to Mars and in halfway to Venus. There’s no formal definition for objects such as this, which are sometimes called quasi-moons or quasi-satellites. They follow a path around Earth, but usually for no more than a few decades. Perhaps the best known of these objects, known as Kamoʻoalewa, was found in 2016, and is considered the smallest, closest, and most stable known quasi-satellite. It has an orbit that has been in a stable resonance with Earth for almost a century, and will remain so for centuries to come, according to calculations by Paul Chodas (Jet Propulsion Laboratory). But this newfound asteroid, if preliminary orbital calculations are correct, will handily eclipse that record. Some estimates say it has circled Earth since at least 100 BC and will likely continue to do so until around AD 3700. If that’s correct, 2023 FW13 would be the most stable quasi-satellite of Earth ever found….

2023-04-05. Spacecraft will explore habitability of Jupiter’s ocean moons. [] By Paul Voosen, Science. Excerpt: Ganymede, Jupiter’s largest moon, is practically a planet. Larger than Mercury, it is the only moon with its own magnetic field, produced by churning molten iron in its core. Its icy crust, more than 100 kilometers thick, …And beneath the crust, many researchers believe, is a salty ocean, kept warm by the moon’s inner heat and Jupiter’s gravitational kneading. …Ganymede is one of three jovian moons that may hold hidden oceans, all potential habitats for life. They are the targets of the $1.6 billion Jupiter Icy Moons Explorer (Juice), a European Space Agency (ESA) mission set for a 13 April launch on an Ariane 5 rocket from French Guiana. …Juice will take 8 years to reach Jupiter. It will spend another 3 years promenading among the moons, eventually ending up in a tight orbit around Ganymede—the first time a spacecraft will orbit a moon other than Earth’s. Ganymede’s sister moon, Europa, has long gotten more attention as a possible home for life and is the target of another spacecraft, NASA’s Europa Clipper, to launch in October 2024. Europa’s icy shell is much thinner than Ganymede’s, perhaps just 15 kilometers thick, and its ocean may sometimes breach the surface—perhaps even sending plumes of water erupting into space. But Europa orbits closer to Jupiter’s intense radiation field, which would disrupt the electronics of any spacecraft lingering nearby. The Clipper, which will arrive a year ahead of Juice thanks to a more powerful rocket, will inspect Europa by swooping past it 50 times….

2023-03-15. Active volcano on Venus shows it’s a living planet. [] By Paul Voosen, Science. Excerpt: Choked by a smog of sulfuric acid and scorched by temperatures hot enough to melt lead, the surface of Venus is sure to be lifeless. For decades, researchers also thought the planet itself was dead, capped by a thick, stagnant lid of crust and unaltered by active rifts or volcanoes. But hints of volcanism have mounted recently, and now comes the best one yet: direct evidence for an eruption. Geologically, at least, Venus is alive. The discovery comes from NASA’s Magellan spacecraft, which orbited Venus some 30 years ago and used radar to peer through the thick clouds. Images made 8 months apart show a volcano’s circular mouth, or caldera, growing dramatically in a sudden collapse. On Earth, such collapses occur when magma that had supported the caldera vents or drains away, as happened during a 2018 eruption at Hawaii’s Kilauea volcano. …The discovery, published today in Science and presented at the Lunar and Planetary Science Conference, makes Venus only the third planetary body in the Solar System with active magma volcanoes, joining Earth and Io, Jupiter’s fiery moon….

2023-02-27. Mercury Isn’t Alone in Orbit, and Scientists Don’t Know Why. [] By Jure Japelj, Eos/AGU. Excerpt: A cloud of dust traces the innermost planet’s orbital path. By all accounts, it shouldn’t be there. …In a new study published in the Planetary Science Journal, scientists tried to trace the genesis of Mercury’s dust. And although they still don’t know how this improbable cloud formed, they do know that it probably has a different origin story than the one escorting our own planet. …Earth’s dust ring formed from the immense cloud of dust, called a zodiacal or interplanetary dust cloud, that pervades the space between planets. …Earth and Venus are massive enough to stall migrating dust, but Mercury is not. That close to the Sun, phenomena including solar winds, solar light, and strong magnetic fields should, quite literally, kick the dust up, and Mercury isn’t large enough to trap the celestial debris in its gravitational pull. …Using data from NASA’s MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) spacecraft, the team identified two craters larger than 40 kilometers in diameter on Mercury’s surface that might be younger than 50 million years. Perhaps collateral debris from these strikes billowed out into space….

2023-02-08. There’s a Ring Around This Dwarf Planet. It Shouldn’t Be There. [] By Kenneth Chang, The New York Times. Excerpt: Quaoar, which orbits the sun in the distant Kuiper belt, is the latest small object shown to have a ring like the ones around Saturn. …Quaoar (pronounced KWA-wahr …is a little less than half the diameter of Pluto and about a third of the diameter of Earth’s moon. It is likely to be big enough to qualify as a dwarf planet, pulled by its gravity into a round shape. …The ring is not visible in telescope images. Rather, astronomers found it indirectly, when distant stars happened to pass behind Quaoar, blocking the starlight. From 2018 through 2021, Quaoar passed in front of four stars, and astronomers on Earth were able to observe the shadow of the eclipses, also known as stellar occultations. However, they also observed some dimming of the starlight before and after the star blinked out. That pointed to a ring obscuring part of the light, an international team of astronomers concluded in Wednesday’s Nature paper…. See also Sky & Telescope article.

2023-02-09. Wind Could Power Future Settlements on Mars. [] By Alakananda Dasgupta, Eos/AGU. Excerpt: Using a sophisticated global climate model adapted to Mars, space scientists explore the hidden potential of wind energy on the Red Planet. …there’s the question of where to find a viable and steady source of energy that would be required for any human mission to Mars. The answer to that question may be blowing in the Martian wind, according to a new study. …with the atmospheric density of Mars being 1% that of Earth, much larger turbine blades would be needed to generate sufficient energy. …Now, a study published in Nature Astronomy has suggested that wind energy could, indeed, be harnessed to power human settlements on Mars. “We were excited to find that there are many locations across the planet where winds are strong enough to provide a really stable power resource” and compensate for a shortfall in solar power using wind turbines, said Victoria Hartwick, lead author of the study and a postdoctoral fellow at NASA Ames Research Center. The team tailored a climate model designed for Earth to simulate Martian climatic conditions and assess winds on the Red Planet….

2023-01-31. Astronomers Find a Dozen More Moons for Jupiter. [] By Jeff Hecht, Sky & Telescope. Excerpt: The biggest planet in the solar system now has the largest family of moons. Since December 20th, the Minor Planet Center (MPC) has published orbits for 12 previously unreported moons of Jupiter. More publications are expected, says Scott Sheppard (Carnegie Institute for Science), who recently submitted observations of the Jovian system taken between 2021 and 2022. The discoveries bring the list of Jovian moons to 92, a hefty 15% increase from the previous tally of 80. …The new finds put Jupiter’s lunar family count well ahead of Saturn’s 83 confirmed moons. However, while Jupiter may have the most moons for now, Saturn might catch up. A search for objects with sizes down to about 3 kilometers across that are moving along with the gas giantsfound three times more near Saturn than near Jupiter….

2023-01-13. Space Dodgers. [] By Shikha SubramaniamRekha Tenjarla and Christian Davenport, The Washington Post. Excerpt: …the space above Earth has been flooded with thousands of satellites, spent rocket stages and the debris from several catastrophic events. As a result, Earth’s lower orbit has been littered with an increasing amount of junk that is careening through space at intense speeds, threatening satellites and even the International Space Station. Last year, the problem became serious enough to prompt the Biden administration to call for the abolishment of tests that destroy satellites in orbit. The announcement came after Russia blew up a dead satellite in 2021, creating a massive debris field that threatened the ISS astronauts along with other satellites. …Every year there are dozens of near-collisions between active satellites or pieces of debris. …There are more than 6,000 active satellites rotating around Earth as of Jan. 9, according to LeoLabs, a company that tracks satellites and debris in Earth’s lower orbit. …The United States and private companies like LeoLabs track tens of thousands of pieces of space debris, including operational and non-operational satellites, rocket stages and unknown objects. But there are many more pieces too small to see. NASA estimates that there are roughly 500,000 objects between 1 and 10 centimeters in diameter orbiting Earth, and that there are more than 100 million particles larger than 1 millimeter. (The agency said that as of January last year, the amount of material in orbit was more than 9,000 metric tons.)…

2023-01-04. Marine Science Goes to Space. [] By Damond Benningfield, Eos/AGU. Excerpt: Cassini discoveries added Enceladus to a growing list of possible ocean worlds in our own solar system—bodies with large amounts of liquid water hidden from view. Some of them could contain more water than all of Earth’s oceans combined. And in addition to Enceladus, planetary scientists have counted at least one other member of the list, Jupiter’s moon Europa, among the ranks of the “possibly habitable.” “There could be life in our own solar system, and we may already have flown past it,” said Christopher German, a senior scientist at Woods Hole Oceanographic Institutionand a coleader of Network for Ocean Worlds (NOW), a NASA-funded effort to advance research on these intriguing bodies. “Instead of just a sci-fi thing, suddenly we have grounds for wondering if there’s life on these nearby worlds—places we have the technology to reach.” …German said scientists have identified five “confirmed” ocean worlds beyond Earth: Jupiter’s moons Callisto, Europa, and Ganymede and Saturn’s moons Enceladus and Titan. That list could be just the tip of the planetary iceberg, however. “There are probably 20 candidates from places that haven’t been studied closely since the Voyagermissions of the 1980s,” German said….

-01-03. Space Missions to Watch in 2023. [] By Sky & Telescope. Excerpts: …SpaceX’s Starship …Axiom Space’s AX2 … to the International Space Station …ESA’s Euclid space telescope …an infrared instrument, aimed at studying dark matter and dark energy …Indian Space Research Organization (ISRO) …X-ray Polarimeter Satellite, …and the Aditya L1 solar mission, headed to the Earth-Sun L1 point. …China’s Xuntian Space Telescope, a sky survey telescope …China also plans to launch two X-ray telescopes in 2023 …The Moon will be bustling in 2023. Three missions [to the Moon] are at least partially NASA-funded through its Commercial Lunar Payload Services. …The Polar Resources Ice Mining Experiment (PRIME 1) is set to launch in June, carrying with it The Regolith and Ice Drill for Exploring New Terrain. The TRIDENT drill will delve three feet deep to bring lunar regolith up to the surface. …[Russian] Roscosmos’ Luna 25 lander …India …Chandrayaan 3 …German-based Rocket Factory Augsburg might also send up a small lunar orbiter, named Harmony …A Google Xprize alumnus, ALINA will land near the Apollo 17 landing site. …Japan Aerospace Exploration Agency’s Smart Lander for Investigating the Moon (SLIM) …ESA’s Jupiter Icy Moons Explorer (JUICE) will …arrive at Jupiter in October 2029. …NASA’s Psyche will depart…for the enigmatic “metal asteroid” 16 Psyche. …Rocket Lab may launch MIT’s ambitious Venus mission in May …drop a small probe into the Venusian atmosphere….

2022-12-20. Mars had long-lived magnetic field, extending chances for 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 window of habitability and reconcile conflicting timelines of the planet’s early history….

2022-12-13. NASA’s 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.

2022-12-06. 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 each of the paleolakes, indicating that the lakes persisted over long periods of time during the Noachian, rather than forming and disappearing quickly. To maintain the filling and drainage of the lakes, liquid water must have been common, with steady inputs into the lake system from precipitation and groundwater, the researchers concluded. The potentially habitable environment in Mars’s distant past indicated by these paleolakes offers an ideal location for future astrobiology and paleoclimate studies, they suggest. (Journal of Geophysical Research: Planets, 2022)….

2022-11-16. Meteorite that landed in Cotswolds may solve mystery of Earth’s 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….

2022-11-10. 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 studyin the Proceedings of the National Academy of Sciences of the United States of America….

2022-10-27. Something Violently Shook the Surface of Mars. It Came From Space. [] 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 meteors too.…

2022-09-30. New Europa Pictures Beamed Home by NASA’s Juno Spacecraft. [] 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.…

2022-09-23. 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 present. Such methane-ice clouds are prominent as bright streaks and spots, which reflect sunlight before it is absorbed by methane gas.…

2022-08-28. Why NASA Is Going Back to the Moon. [] 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.…

2022-08-22. Webb’s 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 standalone view of Jupiter, created from a composite of several images from Webb, auroras extend to high altitudes above both the northern and southern poles of Jupiter. …The Great Red Spot, a famous storm so big it could swallow Earth, appears white in these views, as do other clouds, because they are reflecting a lot of sunlight.… See also NPR article or Washington Post article.

2022-08-01. 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 gap by developing a single atmospheric model consistent with the spectral observations of both planets. They fit near-infrared spectra collected by Hubble, as well as the ground-based Gemini and NASA Infrared Telescope Facility(IRTF) telescopes, to a three-layer aerosol model.…

2022-06-14. 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.…

2022-04-01. What Sounds Captured by NASA’s Perseverance Rover Reveal About Mars. By NASA News. Excerpt: A new study based on recordings made by the rover finds that the speed of sound is slower on the Red Planet than on Earth and that, mostly, a deep silence prevails. ​Listen closely to sounds from Mars, recorded by NASA’s Perseverance: the rover’s mechanical whine and click in a light Martian wind; the whir of rotors on Ingenuity, the Mars helicopter; the crackling strike of a rock-zapping laser. An international team of scientists has done just that, performing the first analysis of acoustics on the Red Planet. Their new study reveals how fast sound travels through the extremely thin, mostly carbon dioxide atmosphere, how Mars might sound to human ears, and how scientists can use audio recordings to probe subtle air-pressure changes on another world – and to gauge the health of the rover. …Most of the sounds in the study, published April 1 in the journal Nature, were recorded using the microphone on Perseverance’s SuperCam, mounted on the head of the rover’s mast. … []

2022-02-15. On Mars, a Year of Surprise and Discovery. By  Kenneth Chang, The New York Times. Excerpt: …NASA’s Perseverance rover …On Feb. 18 last year, the spacecraft carrying the rover pierced the Martian atmosphere at 13,000 miles per hour. …Twelve months later, Perseverance is nestled within a 28-mile-wide crater known as Jezero. From the topography, it is evident that more than three billion years ago, Jezero was a body of water roughly the size of Lake Tahoe, with rivers flowing in from the west and out to the east. One of the first things Perseverance did was deploy Ingenuity, a small robotic helicopter and the first such flying machine to take off on another planet. Perseverance also demonstrated a technology for generating oxygen that will be crucial whenever astronauts finally make it to Mars. The rover then set off on a diversion from the original exploration plans, to study the floor of the crater it landed in. …collect cores of rock — cylinders about the size of sticks of chalk — that are eventually to be brought back to Earth by a future mission [Mars Sample Return]. …data confirm that what orbital images suggested was a river delta is indeed that and that the history of water here was complex. The boulders, which almost certainly came from the surrounding highlands, point to episodes of violent flooding at Jezero. …On April 18 last year, Ingenuity rose to a height of 10 feet, hovered for 30 seconds, and then descended back to the ground. The flight lasted 39.1 seconds. …NASA decided five flights were not enough. When Perseverance set off to explore the rocks to the south, Ingenuity went along, now scouting the terrain ahead of the rover. …During the development of Perseverance’s drill, engineers tested it with a wide variety of Earth rocks. But then the very first rock on Mars that Perseverance tried to drill turned out to be unlike all of the Earth rocks. The rock in essence turned to dust during the drilling and slid out of the tube.… []

2022-02-10. To Make a Big Moon, Start with a Small Planet. By Kimberly M. S. Cartier, Eos/AGU. Excerpt: In a contest of which planet in the solar system has the most relatively massive moon, Earth takes the prize. The Moon is roughly 1% of Earth’s mass, whereas the moons of all the remaining moon-bearing planets—that’s all of them save for Mercury and Venus—are less than one ten thousandth their planets’ masses. …“We think that a giant impact is a very efficient way to form fractionally large moons,” said Miki Nakajima, a planetary scientist at the University of Rochester in New York. Large collisions are thought to be a common occurrence in the chaos of a still-forming solar system, but if all giant impacts formed fractionally large moons, our solar system would be rife with them. …Using computer simulations, Nakajima and her colleagues explored what happens when rocky or icy would-be planets of various sizes collide. The researchers found that after such a major impact, only rocky planets less than 6 times Earth’s mass and icy planets less than 1 Earth mass can form a fractionally large moon out of the collision debris. They published these results in Nature Communications on 1 February.… []

2022-01-21. An Ocean May Lurk Inside Saturn’s ‘Death Star’ Moon. By Kenneth Chang, The New York Times. Excerpt: …For eight years, scientists have been considering that Mimas, seemingly a pockmarked ball of ice frozen hard, might be hiding a secret: an ocean flowing 14 to 20 miles below the surface. In recent years, such ocean worlds — Europa at Jupiter and Enceladus at Saturn, to name two — have jumped to the top of the lists for scientists who are considering places in the solar system where life could have arisen. One NASA spacecraft, Juno, will swoop past Europa for a closer look this year and another mission, Europa Clipper, is to arrive for a dedicated mission there in 2030. But unlike other icy moons known to possess under-ice oceans, Mimas has a surface that offers no hints of cracks or melting that might suggest sloshiness within. It also stretched scientific credulity that the interior of a moon as small as Mimas could be warm enough for an ocean to remain unfrozen. …A planetary scientist who thought the idea of a Mimas ocean was unlikely now finds the thermodynamics to be plausible. …The results were published this week in the journal Icarus.… []

2022-01-17. Mars rover detects carbon signature that hints at past life source. By Paul Voosen, Science Magazine. Excerpt: Since 2012, NASA’s Curiosity rover has trundled across Mars, drilling into rocks and running the grit through a sophisticated onboard chemistry lab, aiming to tease out evidence for life. Today, a team of rover scientists announced an intriguing signal, one that may or may not be evidence of past life, but is, at the very least, surprisingly weird. The team found that the carbon trapped in a handful of rocks probed by the rover is dramatically enriched in light isotopes of carbon. On Earth, the signal would be seen as strong evidence for ancient microbial life. Given that this is Mars, however, the researchers are reluctant to make any grand claims, and they have worked hard to concoct alternative, nonbiological explanations involving ultraviolet (UV) light and stardust. But those alternatives are at least as far-fetched as a scenario in which subterranean microbes emitted the enriched carbon as methane gas. The team concludes the study does “inch up the plausibility” that microbes once existed on the planet—and could still today, says Christopher House, a biogeochemist at Pennsylvania State University, University Park, and lead author of the study, which was published todayin the Proceedings of the National Academy of Sciences.… []

2022-01-05. Stars may form 10 times faster than thought. Ling Xin, Science Magazine. Excerpt: Astronomers have long thought it takes millions of years for the seeds of stars like the Sun to come together. Clouds of mostly hydrogen gas coalesce under gravity into prestellar cores dense enough to collapse and spark nuclear fusion, while magnetic forces hold matter in place and slow down the process. But observations using the world’s largest radio telescope are casting doubt on this long gestational period. Researchers have zoomed in on a prestellar core in a giant gas cloud—a nursery for hundreds of baby stars—and found the tiny embryo may be forming 10 times faster than thought, thanks to weak magnetic fields. “If this is proven to be the case in other gas clouds, it will be revolutionary for the star formation community,” says Paola Caselli from the Max Planck Institute for Extraterrestrial Physics, who was not involved with the research.… []

2021-12-16. Opening a 50-year-old Christmas present from the Moon. By European Space Agency. Excerpt: A pretty special gift unwrapping will soon take place – a piercing tool built by ESA will open a Moon soil container from Apollo 17 that has gone untouched for nearly 50 years. The opening will allow the extraction of precious lunar gases which may have been preserved in the sample.… []

2021-11-11. It Follows Earth Around the Sun. Just Don’t Call It a Moon. By Robin George Andrews, The New York Times. Excerpt: …a little rock would decide to tag along with Earth and the moon on their yearly circumnavigation of the sun. Said rock, 165 feet long, was discovered in 2016 by Hawaii’s Pan-STARRS 1 asteroid-hunting telescope. This eccentric entity’s Hawaiian name, (469219) Kamoʻoalewa, means “wobbling celestial object.” As it repeatedly loops around Earth, this shy body never gets closer than 9 million miles, which is 38 times farther out than the moon. It gets as distant as 25 million miles away before swinging back around for a closer encounter. Calculations of its orbital waltz indicate that it began trailing our planet in a relatively stable manner about a century ago, and it will continue to pirouette around Earth for several centuries to come. …in a paper published Thursday in Communications Earth & Environment, a team of scientists reported … that it appears to be made of the same sort of frozen magmatic matter found on the lunar surface.… []

2021-10-14. Meteorite Crashes Through Ceiling and Lands on Woman’s Bed. By John Yoon and Vjosa Isai, The New York Times. Excerpt: Ruth Hamilton was fast asleep in her home in British Columbia when she awoke to the sound of her dog barking, followed by “an explosion.” She jumped up and turned on the light, only to see a hole in the ceiling. Her clock said 11:35 p.m. …“Oh, my gosh,” she recalled telling the operator, “there’s a rock in my bed.” A meteorite, she later learned. The 2.8-pound rock the size of a large man’s fist had barely missed Ms. Hamilton’s head, leaving “drywall debris all over my face,” she said. Her close encounter on the night of Oct. 3 left her rattled, but it captivated the internet and handed scientists an unusual chance to study a space rock that had crashed to Earth.… []

2021-09-17. A new fleet of Moon landers will set sail next year, backed by private companies. Source: By Joel Goldberg, Science Magazine. Excerpt: Who knew outsourcing could extend to outer space? In some ways, that’s the aim of NASA’s $2.6 billion initiative meant to galvanize the private sector’s development of Moon landers and rovers. The Commercial Lunar Payload Services program has tasked a number of companies—including Pittsburgh-based Astrobotic—with delivering landers to the Moon’s surface twice a year. Astrobotic’s Peregrine lander, roughly the size of a tree house, is set to blast off this year from Cape Canaveral, Florida, as is Houston-based Intuitive Machines’s Nova-C. A second Astrobotic lander, Griffin, is expected to launch in 2023, ferrying the well-equipped, NASA-designed Volatiles Investigating Polar Exploration Rover. Its neutron counter, spectrometers, and specialized drill will seek out evidence of water and attempt to identify its origin. …another Texas-based company, Firefly Aerospace, will deliver tools to study the Moon’s interior heat and another to snap the first extraterrestrial photo of Earth’s magnetic field.… []

2021-06-01. [] – Fifteen Years of Radar Reveal Venus’s Most Basic Facts. Source: By Kimberly M. S. Cartier, Eos/AGU. Excerpt: Venus’s heavy atmosphere tugs the planet’s surface enough to change the length of its day by up to 21 minutes [per day]. …In a recent paper in Nature Astronomy, astronomers used 15 years of radar measurements to reveal a few of these fundamental properties of our closest planetary neighbor that have long remained elusive. …The 70-meter radio antenna at the Goldstone Deep Space Communications Complex in California served as the flashlight, …The researchers carefully measured the timing of the returned waves with two radio telescopes: Goldstone in California and the Green Bank Telescope in West Virginia. …they found that Venus’s spin axis is tilted 2.6392° from its orbital plane and that tilt precesses once every 29,000 Earth years, 3,000 years longer than Earth’s precession. These measurements are 5–15 times more precise than what was achieved by NASA’s Magellan missionto Venus, which ended in 1994…. …They found that the 15-year average length of day on Venus is 243.0226 Earth days (243 days, 32 minutes, and 30 seconds). …their individual measurements of the length of a Venusian day varied by about 3 minutes when measured on consecutive Earth days and up to 21 minutes over the 15-year study period. (Earth’s length of day varies by about 4 milliseconds averaged over 20 years.) …The momentum needed to change Venus’s rotation speed by such a large amount can only be provided by the planet’s thick atmosphere. Momentum transferred from Earth’s atmosphere can lurch the length of a day by a few milliseconds at most, but Venus’s atmosphere has 100 times more mass than Earth’s does and 180 times the momentum. The viscous atmosphere rotates faster than the rest of the planet does, and as it sloshes around, it exchanges momentum with the surface below and changes the surface’s rotation speed….

2021-05-15.[] – China lands rover on Mars in ‘milestone’ achievement. Source: By Antonia Noori Farzan, The Washington Post. Excerpt: China successfully landed a rover-carrying spacecraft on Mars for the first time, state-run media reported Saturday, marking another major victory for the country’s ambitious space program…. China now joins the United States as the only other nations to have successfully landed and operated rovers on Mars, and Chinese President Xi Jinping hailed a “milestone” achievement. The Tianwen-1 spacecraft, launched from the Chinese province of Hainan in July, has been orbiting Mars since February while looking for potential landing sites. Early Saturday, it released an entry capsule containing a lander and a rover that began to plummet through the Mars atmosphere, according to state-run Xinhua News Agency. The entry capsule safely touched down in a flat plane on Mars’ surface at 7:18 a.m. Beijing time (7:18 p.m. Friday Eastern time), though it took about an hour for ground controllers to determine that the mission had been a success, state media reported….  See also New York Times article []

2021-05-07. NASA Mars Helicopter Makes One-Way Flight to New Mission. By Kenneth Chang, The New York Times. Excerpt: On Friday, Ingenuity, which last month became the first machine to fly like an airplane or a helicopter on another world, took off for the fifth time. It made a successful one-way trip to another flat patch of Mars more than the length of a football field away. The spot where it landed will serve as its base of operations for the next month at least, beginning a new phase of the mission where it will serve as a scout for its larger robotic companion, the Perseverance rover…. [

2021-04-19. NASA’s Mars Helicopter Completes First Flight on Another Planet. By Kenneth Chang, The New York Times. Excerpt: A small robotic helicopter named Ingenuity made space exploration history on Monday when it lifted off the surface of Mars and hovered in the wispy air of the red planet. It was the first machine from Earth ever to fly like an airplane or a helicopter on another world. …Like the first flight of an airplane by Wilbur and Orville Wright in 1903, the flight did not go far or last long, but it showed what could be done. Flying in the thin atmosphere of Mars was a particularly tricky technical endeavor, on the edge of impossible because there is almost no air to push against. NASA engineers employed ultralight materials, fast-spinning blades and high-powered computer processing to get Ingenuity off the ground and keep it from veering off and crashing…. [] See also April 22 NY Times article, NASA’s Mars Ingenuity Helicopter Completes Second Flight.
2021-03-23. Remains of impact that created the Moon may lie deep within Earth. By Paul Voosen. Excerpt: Scientists have long agreed that the Moon formed when a protoplanet, called Theia, struck Earth in its infancy some 4.5 billion years ago. Now, a team of scientists has a provocative new proposal: Theia’s remains can be found in two continent-size layers of rock buried deep in Earth’s mantle. For decades, seismologists have puzzled over these two blobs, which sit below West Africa and the Pacific Ocean and straddle the core like a pair of headphones. Up to 1000 kilometers tall and several times that wide, “they are the largest thing in the Earth’s mantle,” says Qian Yuan, a Ph.D. student in geodynamics at Arizona State University (ASU), Tempe. Seismic waves from earthquakes abruptly slow down when they pass through the layers, which suggests they are denser and chemically different from the surrounding mantle rock. …Evidence from Iceland and Samoa suggests the LLSVPs have existed since the time of the Moon-forming impact, says Sujoy Mukhopadhyay, a geochemist at the University of California (UC), Davis, who considers Yuan’s idea plausible but is open to other explanations. Seismic imaging has traced plumes of magma that feed volcanoes on both islands all the way down to the LLSVPs. Over the past decade, Mukhopadhyay and others have discovered that lavas on the islands contain an isotopic record of radioactive elements that formed only during the first 100 million years of Earth history. Moreover, a new picture of the Moon-forming impactor suggests it could have delivered a cargo of dense rock deep inside Earth. The impact theory was developed in the 1970s to explain why the Moon is dry and doesn’t have much of an iron core: In a cataclysmic impact, volatiles like water would have vaporized and escaped, while a ring of less dense rocks thrown up in the collision would have eventually coalesced into the Moon. The theory invoked an impactor the size of Mars or—in recent variants—much smaller. But recent work from Yuan’s co-author, ASU Tempe astrophysicist Steven Desch, suggests Theia was nearly as big as Earth…. [

2021-03-19. The Water on Mars Vanished. This Might Be Where It Went. By Kenneth Chang, The New York Times. Excerpt: Mars once had rivers, lakes and seas. Although the planet is now desert dry, scientists say most of the water is still there, just locked up in rocks. …most of the water, a new study concludes, went down, sucked into the red planet’s rocks. And there it remains, trapped within minerals and salts. Indeed, as much as 99 percent of the water that once flowed on Mars could still be there, the researchers estimated in a paper published this week in the journal Science. Data from the past two decades of robotic missions to Mars, including NASA’s Curiosity rover and the Mars Reconnaissance Orbiter, showed a wide distribution of what geologists call hydrated minerals…. []

2021-02-22. Martian rover sends back ‘overwhelming’ video, audio from the Red Planet. By Catherine Matacic, Science Magazine. Excerpt: Just four martian days after touching down on the Red Planet, NASA’s Perseverance rover has sent back its first video of its new home: a 1-minute arabesque of color and motion captured from four on-board cameras, as the car-size rover dangles from its rocket-propelled descent vehicle, a red-and-white parachute snaps into place, and the pitted surface of Mars comes slowly into view, dark canyons giving way to ripples of dust that look like giant, rust-colored dunes (see video, above). But perhaps even more thrilling, an unexpected gift arrived along with the video and the thousands of new images that were downloaded over the weekend: the first sound recording taken from the surface of Mars…. [] See also Perseverance’s ‘sky crane’ captures Mars descent.
2021-02-18. ‘Touchdown confirmed!’ Perseverance landing marks new dawn for Mars science. By Paul Voosen, Science Magazine. Excerpt: It’s a new day on Mars. NASA’s $2.7 billion Perseverance rover has successfully landed in Jezero crater, alighting just 35 meters away from hazardous boulders it had identified during descent. At about 3:55 p.m. EST, confirmation came back of the rover safely touching its wheels down, resulting in exuberant but socially distanced applause from double-masked engineers at the mission’s control room at the Jet Propulsion Laboratory (JPL)…. []  See also Perseverance’s ‘sky crane’ captures Mars descent; and New York Times article Perseverance’s Pictures From Mars Show NASA Rover’s New Home.

2021-02-06. Martian New Year on Sunday a second chance to start fresh, Earthling. By Chris Knight, The Telegram. Excerpt: …Feb. 7 [2021] marks the beginning of [Martian] year 36. Back at the turn of the (Earth) century …scientists decided they needed a way to count Martian years. Earth years wouldn’t do, since Mars takes 687 days to circle the sun. They picked the Martian spring equinox of 1955 as the start of year one. …Mars, like Earth, has an elliptical orbit that brings it closer to the sun at certain points of the year. It also has an axial tilt of 25 degrees. (Earth’s is just over 23.) Together this creates seasons, with variations in temperature, sunlight and even air pressure, since some of the thin carbon dioxide atmosphere freezes at the poles in the winter. …the overlap of tilt and orbit means northern Martian winters are significantly milder than in the south, with repercussions on any rovers operating in that hemisphere. …Mars has its own days, commonly called sols. …Nick Peper, a systems engineer on the team that operates the Curiosity rover, notes that a sol is almost the same length as a day, but that slight difference can cause problems. Earth’s day is 23 hours and 56 minutes long, the rounding of which gives us a leap day every four years. But a sol is 24 hours 39 minutes, or about 3% longer than a day. About once a month, the two line up briefly. …To keep Martian morning from drifting away from the actual sunrise, scientists merely lengthen each second, minute and hour on Mars by a factor of 1.02749. So a sol on Mars is 24 hours long, but every hour is a little long than its equivalent on Earth. It’s a good fix, though perhaps not as poetic as the one imagined by science-fiction author Kim Stanley Robinson, who in his Mars trilogy writes of “the timeslip,” when clocks stop every sol at midnight for 39 minutes. …“It’s just close enough to lull you into thinking they’re the same length,” Peper says of Martian time units. “And just far enough apart to mess you up.” …Curiosity recently passed its 3,000th sol on Mars…. [] See also Martian Time LookupMars clock, and EarthSky article
Upcoming Martian New Years:
37 – Dec 26 2022
38 – Nov 12 2024
39 – Sep 30 2026
40 – Aug 17 2028

See articles from 2008–2020.