Astro Blog

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 curiou...

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

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

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

https://www.science.org/content/article/evidence-giant-asteroid-strike-may-be-buried-under-wyoming By Paul Voosen, Science Magazine.  Excerpt: Some 280 million years ago, before the rise of the Rocky Mountains—or even the dinosaurs—a 2.5-kilometer-wide asteroid smashed into the supercontinent of Pangaea, near the eastern border of present-day Wyoming. The impact’s heat and shock wave would have killed anything within 400 kilometers, making it one of the largest asteroid strikes in North American history. ...And there the crater may sit, kilometers down, even to this day. That’s the scenario painted in new work. Researchers haven’t found the crater itself, but they have identified a series of 31 smaller craters, each no wider than a U.S. football field. These “secondary” craters would have been formed by boulders ejected by the impact, landing up to 200 kilometers away. It is the first time a secondary crater field—commonly seen on other planetary bodies, including the Moon—has bee...

[ https://www.nytimes.com/2021/08/25/science/asteroid-deflection-collision.html ] Source: By Katherine Kornei , The New York Times.  Excerpt: There’s probably a large space rock out there, somewhere, that has Earth in its cross hairs. Scientists have in fact spotted one candidate —  Bennu, which has a small chance of banging into our planet in the year 2182 . But whether it’s Bennu or another asteroid, the question will be how to avoid a very unwelcome cosmic rendezvous. For almost 20 years, a team of researchers has been preparing for such a scenario. Using a specially designed gun, they’ve repeatedly fired projectiles at meteorites and measured how the space rocks recoiled and, in some cases, shattered. These observations shed light on how an asteroid might respond to a high-velocity impact intended to deflect it away from Earth. At the 84th annual meeting of the Meteoritical Society held in Chicago this month, researchers  presented findings from all of that high-powe...

https://eos.org/articles/an-asteroid-double-disaster-struck-germany-in-the-miocene Source:  By  Katherine Kornei , Eos/AGU.  Excerpt: A Gothic church rises high above the medieval town of Nördlingen, Germany. But unlike most churches, St. George’s is composed of a very special type of rock:  suevite , a coarse-grained breccia that’s formed only in powerful impacts. That discovery and  other lines of evidence  have helped researchers determine that Nördlingen lies within an impact crater. Now, scientists have unearthed evidence that this crater and another one just 40 kilometers away were formed by a “double disaster” of two independent asteroid impacts. ...Our planet is dotted with  nearly 200 confirmed impact structures , and a handful of them appear in close pairs. Some researchers have proposed that these apparent double craters are scars created by  binary asteroids  slamming into Earth at the same time. ...However, scientists have theo...

  https://newsroom.usra.edu/a-steaming-cauldron-follows-the-dinosaurs-demise/ Source:   By Suraiya Farukhi, Ph.D, Universities Space Research Association.  Excerpt: Houston, TX and Columbia, MD. A new study reveals the Chicxulub impact crater may have harbored a vast and long-lived hydrothermal system after the catastrophic impact event linked to the extinction of dinosaurs 66 million years ago. The Chicxulub impact crater, roughly 180 kilometers in diameter, is the best preserved large impact structure on Earth and a target for exploration of several impact-related phenomena. In 2016, a research team supported by the International Ocean Discovery Program and International Continental Scientific Drilling Program drilled into the crater, reaching a depth of 1,335 meters (> 1 kilometer) below the modern-day sea floor. The team recovered rock core samples which can be used to study the thermal and chemical modification of Earth’s crust caused by the impact. The core sam...

https://www.sciencemag.org/news/2019/09/veil-dust-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....

https://eos.org/research-spotlights/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 comp...

https://www.sciencemag.org/news/2019/01/chinese-spacraft-successfully-lands-moons-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 ...

https://www.sciencemag.org/news/2018/10/nasas-next-mars-rover-could-explore-former-mineral-springs-and-fossil-river-delta Source:   By Paul Voosen, Science Magazine. Excerpt: Update: NASA today announced the destination for its next Mars rover, due for launch in 2020. The agency said it would send the rover to the 50-kilometer-wide Jezero crater, which billions of years ago harbored a lake that half filled the 500-meter-deep basin. The crater also contains within its rim a fossilized river delta, the sediments from a river that spilled into the crater—a promising place to search for evidence of past life. [see photo in article; https://www.sciencemag.org/sites/default/files/styles/inline__699w__no_aspect/public/ca_1012NID_Delta_Jezer_Crater_online.jpg?itok=0xVirXxA ] “Getting samples from this unique area will revolutionize how we think about Mars and its ability to harbor life,”  Thomas Zurbuchen, NASA’s associate administrator for science in Washington, D.C., said in a ...

https://www.nasa.gov/press-release/international-team-nasa-make-unexpected-discovery-under-greenland-ice Source:   NASA RELEASE 18-099. Excerpt: An international team of researchers, including a NASA glaciologist, has discovered a large meteorite impact crater hiding beneath more than a half-mile of ice in northwest Greenland. The crater — the first of any size found under the Greenland ice sheet — is one of the 25 largest impact craters on Earth, measuring roughly 1,000 feet deep and more than 19 miles in diameter, an area slightly larger than that inside Washington’s Capital Beltway....   See also 2019-02-12. Radar reveals a second potential impact crater under Greenland’s ice. By Paul Voosen, Science Magazine. [ https://www.sciencemag.org/news/2019/02/radar-reveals-second-potential-impact-crater-under-greenland-s-ice ]

http://www.sciencemag.org/news/2018/07/ancient-craters-mars-reveal-how-planet-s-tilt-has-changed-over-time Source:   By Katherine Kornei, Science Magazine. Excerpt: Earth is a tilted planet—it lists by 23.5°. This “obliquity” causes the North Pole to sometimes tilt toward the sun and sometimes away, giving us the seasons. Now, researchers have revealed how Mars’s obliquity has changed over the last 3.5 billion years, results that could reveal how frequently water ice and snow would have melted to liquid on the Red Planet. To conduct the study, scientists assembled computer models of Mars with different obliquities and bombarded each version of the planet with asteroids. Elliptical craters—created by asteroids hitting the planet at shallow angles—tended to be more evenly distributed over the models with larger obliquities. On more upright planets, the elliptical craters tended to cluster around the equator. By comparing their models with the distribution of more than 1500 ellipt...

Source:   By Sanna Alwmark, Matthias Meier, Scientific American Excerpt: Given the evidence that an asteroid triggered the dinosaur extinction, it makes sense to ask whether showers of asteroids could be to blame for regular extinction events.... https://www.scientificamerican.com/article/could-asteroids-bombard-the-earth-to-cause-a-mass-extinction-in-10-million-years/

Source:   By Jet Propulsion Laboratory News Excerpt:  A relatively large near-Earth asteroid discovered nearly three years ago will fly safely past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance from Earth to the moon. Although there is no possibility for the asteroid to collide with our planet, this will be a very close approach for an asteroid of this size. The asteroid, known as 2014 JO25, was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona -- a project of NASA's NEO Observations Program in collaboration with the University of Arizona. (An NEO is a near-Earth object). Contemporary measurements by NASA's NEOWISE mission indicate that the asteroid is roughly 2,000 feet (650 meters) in size, and that its surface is about twice as reflective as that of the moon. ...Small asteroids pass within this distance of Earth several times each week, but this upcoming close appr...

Source:   By Eric Hand, Science Excerpt: Today, scientists published their first results from a drilling expedition into Chicxulub crater, the buried remnants of an asteroid impact off the Yucatán Peninsula in Mexico that killed off the dinosaurs 66 million years ago. Their discovery of shocked, granite rocks from deep in the crust placed “out of order” on top of sedimentary rocks validates the dynamic collapse theory of formation for Chicxulub’s peak ring, the scientists says. Chicxulub is the only well-preserved crater on Earth with a peak ring, but they abound elsewhere in the inner solar system. Last month, scientists using instruments on a NASA lunar mission showed that the peak rings within the Orientale impact basin were likely to have formed in a similar way as at Chicxulub.... http://www.sciencemag.org/news/2016/11/update-drilling-dinosaur-killing-impact-crater-explains-buried-circular-hills

Source:   By Paul Voosen, Science Excerpt: Some 3.8 billion years ago... A 930-kilometer-wide impact basin perched on the moon’s visible edge, [Mare] Orientale resembles a bull’s-eye, with a smooth interior encircled by three rough rings. ...Do any of the rings match the original crater rim left by the striking asteroid or comet? Now, a new subsurface moon map from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission, published today in Science, suggests that the answer is no. ...GRAIL’s two spacecraft...measured Orientale from a scant altitude of 2 kilometers. At such close range, the spacecraft were exceptionally sensitive to tiny changes in the moon’s gravity caused by buried rocks of different density–giving the GRAIL team a picture of the subsurface, and a better idea of how the impact actually went down. They found that the Orientale strike hollowed out a crater some 320 to 460 kilometers wide—smaller than any of the rings. Within an hour, the crater’s steep wa...

Source:   4.1, 7.2, 8.3 Excerpt: …scientists… revealed new data uncovered by NASA's Lunar CRater Observation and Sensing Satellite, or LCROSS, and Lunar Reconnaissance Orbiter, or LRO. …evidence that the lunar soil within shadowy craters is rich in useful materials, and … has a water cycle. Scientists also confirmed the water was in the form of mostly pure ice crystals in some places. …"NASA has convincingly confirmed the presence of water ice and characterized its patchy distribution in permanently shadowed regions of the moon," said Michael Wargo, chief lunar scientist…. The twin impacts of LCROSS and a companion rocket stage in the moon's Cabeus crater on Oct. 9, 2009, lifted a plume of material that might not have seen direct sunlight for billions of years. As the plume traveled nearly 10 miles above the rim of Cabeus, instruments …made observations of the crater and debris and vapor clouds. After the impacts, grains of mostly pure water ice were lofted into...

Try out this interactive simulation for Crater Impacts. Keywords: asteroid, crater, impact, meteoroid http://simulator.down2earth.eu/