Showing posts from 2019

Parker probe traces solar wind to its source on sun’s surface Source:    By Robert Sanders, UC Berkeley News. Excerpt: A year ago, NASA’s Parker Solar Probe flew closer to the sun than any satellite in history, collecting a spectacular trove of data from the very edge of the sun’s million-degree corona. ...that data has allowed solar physicists to map the source of a major component of the solar wind that continually peppers Earth’s atmosphere, while revealing strange magnetic field reversals that could be accelerating these particles toward our planet. These accelerated particles interact with Earth’s magnetic field, generating the colorful northern and southern lights. But they also have the potential to damage the electrical grid and telecommunications networks on Earth’s surface, threaten orbiting satellites and perhaps endanger astronauts in space. ...“There was a major space weather event in 1859 that blew out telegraph networks on Earth an

Meet Hygiea, the Smallest Dwarf Planet in Our Solar System Source:   By Javier Barbuzano, Eos/AGU. Excerpt: Around 2 billion years ago, two large rock bodies hit each other in the main asteroid belt, a region between the orbits of Mars and Jupiter populated by fragments of rocks of various sizes. The impactor, with a size ranging from 75 to 150 kilometers in diameter, hit a body at least 4 times larger. Astronomers have known about this impact for a long time because it created a whole family of asteroids in the main asteroid belt, formed by the celestial body Hygiea and almost 7,000 smaller asteroids that have similar orbits. Hygiea itself has been considered an asteroid since it was discovered in 1849 by Italian astronomer Annibale de Gasparis. With a diameter just over 430 kilometers, it is the fourth-largest object in the main asteroid belt. New observations obtained with the Very Large Telescope (VLT), located in Chile and operated by the European Sout

Curiosity Rover Reveals Oxygen Mystery in Martian Atmosphere Source:   By Sarah Stanley, Eos/AGU. Excerpt: The Martian atmosphere is thin and cold and consists mostly of carbon dioxide. Although certainly unsuitable for humans, Martian air could hold clues to whether other life-forms live—or once lived—on the Red Planet. Now Trainer et al. report the first measurements of the five major components of the Martian atmosphere captured over several seasonal cycles. ...On average, the data revealed, the equatorial Martian atmosphere consists of 95% carbon dioxide, 2.59% nitrogen, 1.94% argon, 0.161% oxygen, and 0.058% carbon monoxide. However, throughout the year, some of these concentrations vary widely because of seasonal freezing of carbon dioxide at the planet’s poles, which periodically removes much of this gas from the atmosphere. Seasonal polar freezing—and subsequent thawing—of carbon dioxide also causes atmospheric pressure to rise and fall t

How Enceladus got its water-spewing tiger stripes Source:   By Adam Mann, Science Magazine. Excerpt: Researchers say they have solved a long-standing mystery about Saturn’s tiny, frozen moon Enceladus: why its south pole features long, water-spewing geysers known as tiger stripes. The study could also help explain why these unique formations aren’t seen on any other satellite in the solar system. Enceladus became a star attraction in 2005, when NASA’s Cassini mission photographed enormous jets of water ice and vapor emanating from four parallel slashes near its south pole. Since then, researchers have detected organic molecules and hydrogen in the jets—potential food for microbes—making Enceladus one of the top destinations in the search for life elsewhere in the Solar System. ...As it orbits around Saturn, Enceladus experiences gravitational tidal forces that squeeze and heat it. ...According to the new study, led by Douglas Hemingway of the

Voyager 2’s Discoveries From Interstellar Space Source:   By Kenneth Chang. The New York Times. Excerpt: The Voyager 2 spacecraft burst out of the bubble of gases expanding from the sun and into the wild of the Milky Way a year ago. It was the second spacecraft to cross that boundary and directly observe the interstellar medium. Its faster-moving twin, Voyager 1, made the crossing six years earlier, in August 2012. Launched 42 years ago, when Jimmy Carter was president, the twin spacecraft have persisted far longer than envisioned, as has their ability to send scientific findings home to Earth. In a series of papers published on Monday in Nature Astronomy [], scientists report what Voyager 2 observed at the boundary of the solar wind’s bubble and beyond....

Veil of dust from ancient asteroid breakup may have cooled Earth Source:   By Joshua Sokol, Science Magazine. Excerpt: Faced with a dangerously warming world, would-be geoengineers have dreamed up ways to quickly turn down the heat. One proposed technique: spreading a veil of dust that would sit in space or Earth's atmosphere and reflect sunlight. Researchers say they have now found evidence for a similar experiment that played out naturally, 466 million years ago, when an asteroid out in space exploded into bits. Dust from the breakup blanketed the planet, says Birger Schmitz, a geologist at Lund University in Sweden, plunging it into an ice age that was soon followed by an explosion in animal life. The ancient episode offers both encouragement and caution for geoengineers. If Schmitz is right, it dramatically demonstrates how dust can cool the planet. But the deep freeze is a lesson in potential unintended consequences....

Water found for first time on potentially habitable planet Source:   By Pallab Ghosh, BBC News. Excerpt: Astronomers have for the first time discovered water in the atmosphere of a planet orbiting within the habitable zone of a distant star. The finding makes the world - which is called K2-18b - a plausible candidate in the search for alien life. ...Details were published in the scientific journal Nature Astronomy [ ]. ...K2-18b is 111 light-years - about 650 million million miles - from Earth, too far to send a probe. ...The team behind the discovery looked through the planets discovered by the Hubble Space Telescope between 2016 and 2017. The researchers determined some of the chemicals in their atmosphere by studying the changes to the starlight as the planets orbited their suns. The light filtered through the planets' atmospheres was subtly altered by the composition of the atmosphere.Only K2-18b revealed  the molecular signature

A Supernova Was Hiding in Antarctica’s Snow Source:   By Katherine Kornei, The New York Times. Excerpt: Earth is continuously plowing through extraterrestrial dust. Tens of thousands of tons of the stuff, mostly from asteroids and comets, settles all over the planet every year. ...Recently, scientists analyzed dust collected from Antarctic snow and found an excess of radioactive iron. After ruling out contamination from nuclear weapons testing and other sources, the team concluded that the iron was produced by supernovas, fleeting explosions of stars more massive than the sun. This discovery suggests that stellar blasts might have rocked Earth and the rest of the solar system in the not-too-distant past. The results were published on Aug. 12 in Physical Review Letters [ ]. Meteorite hunters are drawn to Antarctica because the space rocks, which are dark, stand out against the snow. Do

Artemis 1 Mission to the Moon Source:   NASA.

Jupiter’s annual portrait is a beaut Source:   By Robert Sanders, UC Berkeley News. Excerpt: Just as families record the changing faces of their kids as they grow older, the Hubble Space Telescope each year captures the changing faces of the solar system’s four colorful gas-giant planets. The newest photo in that yearbook is a portrait of Jupiter taken June 27 that reveals clouds swirling in the planet’s turbulent atmosphere that are painted with a color palette more intense than seen in previous years. Mike Wong, an associate researcher in UC Berkeley’s Department of Astronomy and one of three members of the Hubble team taking the photos, was most intrigued by a mysterious color change around Jupiter’s equator: The formerly white equatorial belt has become orangish. And, surprisingly, Red Spot Jr., a planet that was red the last time it was photographed, has turned white. It is now back to the way it looked at its formation in 2000, before it f

When a Mega-Tsunami Drowned Mars, This Spot May Have Been Ground Zero Source:   By Robin George Andrews, New York Times.   Excerpt: A new study, published last month in the Journal of Geophysical Research: Planets, suggests that a 75-mile-wide impact scar in the Martian northern lowlands is to the red planet what the Chicxulub crater is to Earth: the mark of a meteor that generated a mega-tsunami when the planet was relatively young. If accurate, the finding adds evidence to the hypothesis that Mars once had an ocean, and would have implications for our search for life there....

NASA’s TESS Satellite Spots ‘Missing Link’ Exoplanets See also Newly discovered exoplanet trio could unravel the mysteries of super-Earth formation in Science Magazine . [ ] Source:   By Dennis Overbye, New York Times. Excerpt: NASA’s new planet-hunting spacecraft, the Transiting Exoplanet Survey Satellite, is now halfway through its first tour of the nearby universe. It has been looking for worlds that might be fit for you, me or some other form of life, and as usual, nature has been generous in its rewards. Since its launch in April 2018, TESS has already discovered 21 new planets and 850 more potential worlds that have yet to be confirmed, all residing within a few dozen light years of the sun and our own solar system, according to George Ricker, an M.I.T. researcher who heads the TESS project. So far, he said, TESS “has far exceeded our

NASA Rover on Mars Detects Puff of Gas That Hints at Possibility of Life Source:   By Kenneth Chang, The New York Times. Excerpt: Mars, it appears, is belching a large amount of a gas that could be a sign of microbes living on the planet today. In a measurement taken on Wednesday, NASA’s Curiosity rover discovered startlingly high amounts of methane in the Martian air, a gas that on Earth is usually produced by living things. The data arrived back on Earth on Thursday, and by Friday, scientists working on the mission were excitedly discussing the news, which has not yet been announced by NASA. ...Methane, if it is there in the thin Martian air, is significant, because sunlight and chemical reactions would break up the molecules within a few centuries. Thus any methane detected now must have been released recently. On Earth, microbes known as methanogens thrive in places lacking oxygen, such as rocks deep underground and the digestive tracts of animals, and they release methane as a was

Jupiter's Great Red Spot (GRS) is shrinking

• comparison image between Pioneer’s visit(s) and a more recent ground-based image - • HST images - • animation of GRS shrunk another 20% or so - • Christopher Go - • Anthony Wesley (see 2019 Apr) - • Damian Peach (2019) -

The Quaking, Shrinking Moon Source:   By Rachel Crowell, Eos/AGU. Excerpt: New evidence suggests that the Moon may still be tectonically active. Between 1969 and 1977, lunar seismometers at four Apollo landing sites recorded 28 shallow moonquakes. However, the data transmitted by those seismometers were low resolution by current standards, making it difficult to locate the moonquakes’ epicenters. ...The orbital timing of these quakes was also significant. Seven of them occurred at near apogee, when compression of the Moon is near its maximum and fault slip events are likely to occur, according to the study. ...Although these results illustrate an exciting discovery, they also show the need for putting modern seismometers on the Moon....  

A Violent Splash of Magma That May Have Made the Moon Source:   By Robin George Andrews, The New York Times. Excerpt: ...A study [ ] published on Monday in Nature Geoscience suggests that the moon was forged from the fires of an ocean of magma sloshing over baby Earth’s surface. If correct, this model may solve a longstanding paradox. Lunar meteorites and samples collected during the Apollo missions show that the moon and Earth have remarkably similar geochemical fingerprints. Scientists suspect that this was likely the result of a giant impactor the size of Mars, known as Theia, that slammed into a young Earth and sent into orbit a spiral of material that coalesced into the moon. Countless computer simulations show that this is possible, but there’s a problem. Such an impact on a relatively solid Earth would have created a moon made mostly out of Theia, not Earth (at least in simulations resulting in the Earth-moon s

First marsquake detected by NASA’s InSight mission Source:   By Paul Voosen, Science Magazine. Excerpt: After several months of apprehensive waiting on a quiet surface, NASA’s InSight lander has registered a sweet, small sound: the first marsquake ever recorded. On 6 April, the lander’s seismometer detected its first verifiable quake, NASA and its European partners announced today. The quake is tiny, so small that it would never be detected on Earth amid the background thrum of waves and wind. But Mars is dead quiet, allowing the lander’s sensitive seismometer to pick up the signal, which resembles similar surface ripples detected traveling through the moon’s surface after moonquakes. The quake is so small that scientists were unable to detect any waves tied to it that passed through the martian interior, defying efforts to estimate its exact location and strength, says Philippe Lognonné, a planetary seismologist at Paris Diderot University who l

How the Moon Got Its Concentric Rings Source:   By Emily Underwood, Eos/AGU. Excerpt: The Moon is pockmarked with impact craters from collisions with meteorites and asteroids, some as big as 1,000 kilometers in diameter. These massive impact craters contain three or more concentric rings, a mysterious feature that has long intrigued scientists interested in how Earth’s early surface and those of other planets evolved. Now a new study, in which scientists simulated an asteroid bigger than New York City slamming into a Moon-like object, explores how such rings form. ...To get a fresh perspective on this complex crater structure, Johnson et al. took advantage of data from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission: two washing machine–sized spacecraft that orbit the Moon and produce a high-resolution map of its gravitational field. Using this new, 10-kilometer-scale data, the authors were able to build a high-resolution computer

The first picture of a black hole opens a new era of astrophysics Source:   By Lisa Grossman and Emily Conover, ScienceNews. Excerpt: A world-spanning network of telescopes called the Event Horizon Telescope [EHT; ] zoomed in on the supermassive monster in the galaxy M87 to create this first-ever picture of a black hole.  ...“We’ve been studying black holes so long, sometimes it’s easy to forget that none of us have actually seen one,” France Córdova, director of the National Science Foundation....  ...The image also provides a new measurement of the black hole’s size and heft. ...Estimates made using different techniques have ranged between 3.5 billion and 7.22 billion times the mass of the sun. But the new EHT measurements show that its mass is about 6.5 billion solar masses. ...The team has also determined the behemoth’s size — its diameter stretches 38 billion kilometers — and that the black hole spins clockwise. “M87 is a m

A Japanese spacecraft may have just blown a crater in a distant asteroid Source:   By Dennis Normile, Science Magazine. Excerpt: Japan’s Hayabusa2 mission continued its unprecedented explorations today by apparently creating an artificial crater in an asteroid, a space exploration first. Officials confirmed that the operation to fire a projectile into asteroid Ryugu went smoothly, though as of early evening Japan time they were still trying to confirm whether a crater had actually been formed. ...Developed by the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science in Sagamihara, Hayabusa2 was launched in December 2014 and traveled 3.2 billion kilometers through space before reaching its home position 20 kilometers away from Ryugu, a diamond-shaped asteroid about 1 kilometer by 900 meters in size orbiting between Earth and Mars. The mission’s objective is to collect samples both from Ryugu’s surface and its interior and re

Astronomers spy an iron planet stripped of its crust around a burned-out star Source:   By Daniel Clery, Science Magazine. Excerpt: In a glimpse of what may be in store for our own solar system, astronomers have discovered what appear to be the shattered remains of a planet orbiting a white dwarf, the burned-out ember of a star like our sun. If the team’s calculations are correct, the orbiting object may be the iron core of a small planet that had its outer layers ripped off by the white dwarf’s intense gravity. Although astronomers know of thousands of exoplanets in the Milky Way, they struggle to see anything much smaller than Earth. The new object is by far the smallest, more of an asteroid than a planet. ...Finding the planetesimal, 400 light-years from Earth, wasn’t easy.  ...Most exoplanets can’t be seen directly, but are found when they cast a shadow crossing the face of their star or when they tug their star back and forth with the force of t

66 million-year-old deathbed linked to dinosaur-killing meteor Source:   By Robert Sanders, Berkeley News, UC Berkeley. Excerpt: The beginning of the end started with violent shaking that raised giant waves in the waters of an inland sea in what is now North Dakota. Then, tiny glass beads began to fall like birdshot from the heavens. The rain of glass was so heavy it may have set fire to much of the vegetation on land. In the water, fish struggled to breathe as the beads clogged their gills. The heaving sea turned into a 30-foot wall of water when it reached the mouth of a river, tossing hundreds, if not thousands, of fresh-water fish — sturgeon and paddlefish — onto a sand bar and temporarily reversing the flow of the river. Stranded by the receding water, the fish were pelted by glass beads up to 5 millimeters in diameter, some burying themselves inches deep in the mud. The torrent of rocks, like fine sand, and small glass beads continued for

Fossil Site Reveals Day That Meteor Hit Earth and, Maybe, Wiped Out Dinosaurs. Source:    By William J. Broad and Kenneth Chang, The New York Times.  Excerpt: Sixty-six million years ago, a giant meteor slammed into Earth off the coast of modern-day Mexico. Firestorms incinerated the landscape for miles around. Even creatures thousands of miles away were doomed on that fateful day, if not by fire and brimstone, then by mega-earthquakes and waves of unimaginable size. Now, scientists have unearthed a remarkable trove of fossils that appear to date from the very day of the impact. The burial site consists of more than four feet of sediments and organic remains that were dumped in North Dakota almost instantly and transformed into rock over the eons. It evidently captures, in unparalleled detail, the repercussions of the giant doomsday rock.... ...When the meteor smashed into waters near what is now Mexico’s Yucatán Peninsula, it left a giant crater known as Chicxulub and prompted uphe

The Asteroid Was Shooting Rocks Into Space. ‘Were We Safe in Orbit?’ Source:  By Kenneth Chang and Shannon Stirone, The New York Times. Excerpt: HOUSTON — The asteroid Bennu, with the shape of a spinning top, turns out to be extremely rugged. That is going to make it difficult for a NASA spacecraft, Osiris-Rex, to vacuum up a sample to take back to Earth. It was designed to collect sand and gravel, not boulders. In addition, Bennu is shooting back. “We are seeing Bennu regularly eject material into outer space,” said Dante Lauretta, Osiris-Rex’s principal investigator.... The NASA spacecraft, which launched in 2016, entered orbit around Bennu on Dec. 31. It is not the only spacecraft from Earth exploring an asteroid. Hayabusa2, launched by Japan’s space agency in 2014, began orbiting the asteroid Ryugu last year. Its mission is also to collect samples for return to our planet for study, .... Both missions have found that the objects they are studying have terrain much more jagged

How Ultima Thule Is Like a Sticky, Pull-Apart Pastry Source:   By Kenneth Chang, The New York Times. Excerpt: ...New Horizons traveled some 4 billion miles to take a close-up look at this 22-mile-long world in the solar system’s icy Kuiper belt beyond Neptune; it is officially designated as 2014 MU69 and nicknamed Ultima Thule. ...a small shard that has been frozen and almost unchanged since it formed 4.5 billion years ago. Ultima Thule was ... full of surprises. The shape turned out to be unlike anything seen in the solar system. ...two objects that at some stage touched and stuck together, like a snowman. Then the scientists discovered that the two lobes of Ultima Thule were not spherical, but more like lumpy pancakes. The larger lobe is also flatter than the smaller one. ...a change from older ideas of planetary formation: that objects called planetesimals grew slowly and steadily in size. Ultima Thule suggests an alternative scenario in which a bunch of sim

Untouched moon samples from the Apollo missions will be studied for the first time Source:   By Ashley Strickland, CNN. Excerpt: After sitting untouched in storage for nearly 50 years, lunar samples collected during the Apollo 15, 16 and 17 missions will be studied for the first time, NASA Administrator Jim Bridenstine announced Monday. ...NASA selected nine teams to study the moon samples and awarded a total of $8 million for their research. "By studying these precious lunar samples for the first time, a new generation of scientists will help advance our understanding of our lunar neighbor and prepare for the next era of exploration of the Moon and beyond," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate, in a statement. ...The three samples from the final three Apollo missions have never been exposed to our atmosphere on Earth. Six of the nine teams will study the Apollo 17 sample, delivered to Earth in a vacuum-sealed drive tub

The first planet Kepler spotted has finally been confirmed 10 years later Source:   By Lisa Grossman, Science News. Excerpt: A decade after being found, the first exoplanet candidate spotted by the Kepler space telescope has been confirmed as a real world. The planet orbits a star initially dubbed KOI 4, for Kepler Object of Interest 4 (KOIs 1 through 3 were known before Kepler launched in March 2009). ...The Kepler team originally thought the star was about 1.1 times the width of the sun, which would make the planet about the size of Neptune. But then astronomers saw a second dip in starlight as the world passed behind the star, called a secondary eclipse. That second dip shouldn’t be visible for such a small planet, so the exoplanet candidate was dismissed as a false alarm. ...KOI 4 is actually about three times the width of the sun, meaning its planet would be about three times as large as first estimated — or a bit larger than Jupiter, the team found. That’s big

There’s probably another planet in our solar system. Source:   By MIT Technology Review. Excerpt: When it comes to exploring the solar system, astronomers have an embarrassing secret. Despite 400 years of stargazing, they have discovered only two large objects that would have been unknown to the ancients: Uranus in 1781 and Neptune in 1846. That’s not for lack of trying. The possibility of an unknown planet just beyond observational reach has attracted astronomers like moths to a flame. A few have been successful. Several astronomers together discovered Neptune after noticing that the other planets were being gravitationally nudged by an unknown mass. Neptune didn’t entirely resolve these discrepancies, and the hunt continued into the 20th century, culminating in Pluto’s discovery in 1930. But Pluto turned out to be so small that it couldn’t account for the nudging. Indeed, it was later humiliatingly demoted to a “dwarf planet.” ...  

Life probably exists beyond Earth. So how do we find it? Source:  By Jamie Shreeve, Spencer Lowell, Dana Berry, National Geographic  Excerpt:  Sara...Seager, 47, is an astrophysicist. Her specialty is exoplanets, namely all the planets in the universe except the ones you already know about revolving around our sun. On a blackboard, she has sketched an equation she thought up to estimate the chances of detecting life on such a planet. Beneath another blackboard filled with more equations is a clutter of memorabilia, including a vial containing some glossy black shards. ...When Seager entered graduate school in the mid-1990s, we didn’t know about planets that circle their stars in hours or others that take almost a million years. We didn’t know about planets that revolve around two stars, or rogue planets that don’t orbit any star but just wander about in space. In fact, we didn’t know for sure that any plan

Update: Japanese spacecraft safely lands and leaves asteroid surface in effort to collect samples Source:   By Dennis Normile, Science Magazine. Excerpt: *Update, 22 February, 6:33 a.m.: Japan's Hayabusa2 spacecraft successfully executed a challenging touchdown on asteroid Ryugu today at about 7:30 a.m. Japan time. Officials from the Japan Aerospace Exploration Agency confirmed that during an autonomous operation Hayabusa2 landed momentarily within a target site just 6 meters wide and fired a steel pellet into the surface of the asteroid in hopes of scattering fragments into a collection horn. Mission planners hoped to collect 10 grams of material, but the amount won't be known for sure until the sample container is returned to Earth in 2020. Hayabusa2 could make two more touchdowns to gather additional samples. [4 January story previewing its historic touchdown plans:] YONAGO, JAPAN—Japan's Hayabusa mission made history in 2010 for bringing back to Earth the first samples e

Apollo May Have Found an Earth Meteorite on the Moon Source:   By Kimberly M. S. Cartier, Eos/AGU. Excerpt: The meteorite may have been blasted off of Earth during an impact, mixed with lunar rocks, and brought back to Earth 4 billion years later by astronauts. A rock sample brought back by Apollo 14 may contain the first evidence of Earth material on the Moon. New analysis of zircon grains in one lunar sample suggests that the zircon formed under conditions typical in Earth’s crust and not on the Moon. ...“I expect there could be a bit of controversy because this is the first of its kind,” [Jeremy] Bellucci said. “Hopefully,” he said, “it inspires a search for more Earth materials and further analyses on these samples.”...

How Long Is a Day on Saturn? Source:   By Nadia Drake, The New York Times. Excerpt: For decades, it was a nagging mystery — how long does a day last on Saturn? Earth pirouettes around its axis once every 24 hours or so, while Jupiter spins comparatively briskly, once in roughly 9.8 Earth-hours. And then there is Venus, a perplexingly sluggish spinner that takes 243 Earth-days to complete a full rotation. With Saturn, it turns out the answer rippled in plain view, in the planet’s lustrous rings. After reading small, spiraling waves in those bands, sculpted by oscillations from Saturn’s gravity, scientists reported this month in the Astrophysical Journal that one Saturnian day is a mere 10 hours, 33 minutes and 38 seconds long, measured in Earth time. ...Saturn has been stubbornly secretive about its days. Its buttery clouds don’t bear helpful markings that scientists might use to track the planet’s rotation, and they can't easily use its near

Moon’s craters reveal recent spike in outer space impacts on Earth Source:   By Paul Voosen, Science Magazine. Excerpt: It has long been thought that as the solar system grows older and stodgier, the number of asteroids and comets colliding with Earth and other planets has steadily gone down. But a new study reveals what appears to be a dramatic 2.5 times increase in the number of impacts striking Earth in the past 300 million years. ...Scientists used a thermal camera on NASA’s Lunar Reconnaissance Orbiter to examine the number of large, heat-retaining rocks in the moon’s craters; those rocks are eventually ground to dust by minute meteorite impacts. By looking at previously dated craters, these rocks have been established as a reliable dating technique—the more intact the rocks, the younger the crater. In the new study, the team found a surprising abundance of young craters, seemingly matching the number on Earth. That means, they write today in

Modeling the Climates of Worlds Beyond Earth Source:   By  Katherine Kornei, Eos/AGU. Excerpt: Climate modeling isn’t limited just to planet Earth anymore. In recent decades, researchers have begun modeling the climates of other planets in the solar system and are now simulating conditions on faraway worlds orbiting other stars in the Milky Way galaxy. ...There’s no shortage of planets to study: Nearly 4,000 extrasolar planets (exoplanets) have already been found using such instruments as the Kepler Space Telescope. The team for NASA’s Transiting Exoplanet Survey Satellite (TESS), which was just launched last year, announced the discovery of its third exoplanet at the AAS meeting last week. And an increasing number of worlds are being found that resemble our home planet in size, Shields said. “We are now in the Earth-sized regime.” ...Shields is also studying the climatic effects of ice on exoplanets. Here on Earth, the majority of the sunlight that strikes

How an ancient cataclysm may have jump-started life on Earth Source:   By Robert F. Service, Science Magazine Excerpt: ATLANTA—A cataclysm may have jump-started life on Earth. A new scenario suggests that some 4.47 billion years ago—a mere 60 million years after Earth took shape and 40 million years after the moon formed—a moon-size object sideswiped Earth and exploded into an orbiting cloud of molten iron and other debris. The metallic hailstorm that ensued likely lasted years, if not centuries, ripping oxygen atoms from water molecules and leaving hydrogen behind. The oxygens were then free to link with iron, creating vast rust-colored deposits of iron oxide across our planet's surface. The hydrogen formed a dense atmosphere that likely lasted 200 million years as it ever so slowly dissipated into space. After things cooled down, simple organic molecules began to form under the blanket of hydrogen. Those molecules, some scientists think, even

Another Day, Another Exoplanet: NASA’s TESS Keeps Counting More Source:   By Dennis Overbye, The New York Times. Excerpt: NASA’s new planet-hunting machine, the Transiting Exoplanet Survey Satellite, or TESS, is racking up scores of alien worlds. Less than a quarter of the way through a two-year search for nearby Earthlike worlds, TESS has already discovered 203 possible planets, according to George R. Ricker, an astrophysicist at the Massachusetts Institute of Technology, and the leader of the project. Three of those candidates already have been confirmed as real planets by ground-based telescopes. ...All of these worlds would be located within 300 light years from here, our cosmic backyard, and close enough to be inspected by future telescopes, such as NASA’s ever-upcoming James Webb Space Telescope, for signs of atmospheres, habitability and, perhaps, life. ...In the last three decades, and aided by NASA’s planet-hunting Kepler spacecraft, astronomers have concluded that th

Chinese spacecraft successfully lands on moon’s far side and sends pictures back home Source:   By Dennis Normile, Science Magazine. Excerpt: China’s Chang’e-4 spacecraft successfully landed on the far side of the moon this morning Beijing time, accomplishing a worldwide first in lunar exploration. China’s state media confirmed that touchdown occurred at 10:26 a.m. local time; later in the day, the China National Space Administration released the first close-ups of the surface of the far side, taken by Chang’e-4 after it landed. ...Chang’e-4 was launched on 8 December 2018 from the Xichang Satellite Launch Center in Sichuan province. The landing site is in the Von Kármán crater in the South Pole-Aitken Basin. The basin was likely formed by a giant asteroid impact that might have brought material from the moon's upper mantle to the surface; studying samples taken there might offer scientists the chance to learn more about the composition of the

NASA's New Horizons Mission Reveals Entirely New Kind of World Source:  By New Horizons Mission. Excerpt: Scientists from NASA's New Horizons mission released the first detailed images of the most distant object ever explored — the Kuiper Belt object nicknamed Ultima Thule. Its remarkable appearance, unlike anything we've seen before, illuminates the processes that built the planets four and a half billion years ago. "This flyby is a historic achievement," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. "Never before has any spacecraft team tracked down such a small body at such high speed so far away in the abyss of space. New Horizons has set a new bar for state-of-the-art spacecraft navigation." The new images — taken from as close as 17,000 miles (27,000 kilometers) on approach — revealed Ultima Thule as a "contact binary," consisting of two connected spheres. End to end, the

Japan’s asteroid mission faces ‘breathtaking’ touchdown Source:   By Dennis Normile, Science Magazine. Excerpt: "By looking at the details of every asteroid ever studied, we had expected to find at least some wide flat area suitable for a landing," says Yuichi Tsuda, Hayabusa2's project manager at the Japan Aerospace Exploration Agency's Institute of Space and Astronautical Science (ISAS), which is headquartered in Sagamihara. Instead, when the spacecraft reached Ryugu in June 2018—at 290 million kilometers from Earth—it found a cragged, cratered, boulder-strewn surface that makes landing a daunting challenge. The first sampling touchdown, scheduled for October, was postponed until at least the end of this month, and at a symposium here on 21 and 22 December, ISAS engineers presented an audacious new plan to make a pinpoint landing between closely spaced boulders....