Showing posts from January, 2019

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....