Posts

Ancient beaches testify to long-ago ocean on Mars

By -
By Robert Sanders , UC Berkeley News.  Excerpt: Mars today is a cold, dry, dusty planet with its only obvious water locked up in frozen polar ice caps. But billions of years ago, it appears to have had sandy beaches lapped by waves along the shoreline of a vast ocean. The evidence for beaches on Mars comes from a Chinese rover, called Zhurong, that landed on the planet in 2021. During its short life it detected evidence of underground beach deposits in an area thought to have once been the site of an ancient sea, bolstering the idea that the planet long ago had large bodies of water. ...between May 2021 and May 2022, Zhurong traveled 1.9 kilometers (1.2 miles) roughly perpendicular to escarpments thought to be an ancient shoreline from a time — 4 billion years ago — when Mars had a thicker atmosphere and a warmer climate. Along its path, the rover used ground penetrating radar (GPR) to probe up to 80 meters (260 feet) beneath the surface. ...“The structures don’t look like sand du...
Read more

Jupiter’s Moon Callisto Is Very Likely an Ocean World

By -
By Sarah Stanley , Eos/AGU.  Excerpt: A closer look at previously disregarded observations reveals stronger evidence that a deep ocean lies beneath Callisto’s icy surface. ... Cochrane et al.  have revisited the Galileo data in more detail. Unlike in prior studies, this team incorporated all available magnetic measurements from Galileo’s eight close flybys of Callisto. Their expanded analysis much more strongly suggests that Callisto hosts a subsurface ocean....  Full article at https://eos.org/research-spotlights/jupiters-moon-callisto-is-very-likely-an-ocean-world . 
Read more

Climatic and ecological responses to Bennu-type asteroid collisions

By -
By Lan Dai  and  Axel Timmermann , ScienceAdvances.  Abstract summary: Asteroid Bennu has a 0.037% chance of colliding with Earth in 2182 CE.  The potential collision of such medium-sized asteroids would inject dust into the atmosphere and disrupting climate, vegetation, and marine productivity. Simulations show global temperature drop of 4°C, reduced precipitation, and significant decreases in terrestrial and marine net primary productivity....  Full article at https://www.science.org/doi/10.1126/sciadv.adq5399 .  See also Life’s Building Blocks Found in Bennu Samples (Eos/AGU)
Read more

Asteroid 2024 YR4 reaches level 3 on the Torino Scale

By -
By Center for NEO Studies (CNEOS), JPL/CalTech.  Excerpt: CNEOS analysis of near-Earth asteroid 2024 YR4, which is estimated to be about 40 to 90 meters wide, indicates it has a more than 1% chance of impacting Earth on Dec. 22, 2032 — which also means there is almost a 99% chance this asteroid will not impact. These analyses will change from day to day as more observations are gathered. The CNEOS analyses are used for NASA’s contribution to the  International Asteroid Warning Network (IAWN) . After the impact probability for this asteroid reached 1%, IAWN issued its official  notification  for the potential impact....  Full article at https://cneos.jpl.nasa.gov/news/news210.html .  See also: International Asteroid Warning Network - https://iawn.net/obscamp/2024YR4/index.shtml , explanation of the Torino Scale on Wikipedia - https://en.wikipedia.org/wiki/Torino_scale , European Space Agency Near-Earth Objects Coordination Center - https://neo.ssa.esa.int/-...
Read more

Abundant ammonia and nitrogen-rich soluble organic matter in samples from asteroid (101955) Bennu

By -
By Daniel P. Glavin et al, Nature Astronomy.  Abstract Excerpt: Organic matter in meteorites reveals clues about early Solar System chemistry and the origin of molecules important to life.... Samples returned from the B-type asteroid Bennu by the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer mission ...show that Bennu samples are volatile rich, with more carbon, nitrogen and ammonia than samples from asteroid Ryugu and most meteorites. ...Bennu’s parent asteroid developed in or accreted ices from a reservoir in the outer Solar System where ammonia ice was stable. ...The transport and delivery of organic compounds from these bodies could have been a source of molecules available for the emergence of life on Earth and potentially elsewhere....  Full article at https://www.nature.com/articles/s41550-024-02472-9 .  See also Nature article An evaporite sequence from ancient brine recorded in Bennu samples [Brines ...are environment...
Read more

Scientists Finally Get a Good Look at a Disintegrating Exoplanet

By -
By Javier Barbuzano , Eos/AGU.  Excerpt: The James Webb Space Telescope offers astronomers a rare glimpse into the chemical composition of a rocky planet’s interior—and the results are “very surprising.” ...disintegrating planet, K2-22b, ...Discovered in 2015, ...orbits a small star 787 light-years away, completing one orbit every 9 hours. ...The spectroscopic results are “very surprising,” said University of Leeds astronomer  Richard Booth , who wasn’t involved with the study. “We expected to see a composition akin to Earth’s mantle with minerals like magnesium silicate, and they see hints of that,” Booth said. “You just wouldn’t expect any icy material surviving at these temperatures.”....  Full article at https://eos.org/articles/scientists-finally-get-a-good-look-at-a-disintegrating-exoplanet . 
Read more

Astronomers just deleted an asteroid because it turned out to be Elon Musk’s Tesla Roadster

By -
By Mark Zastrow , Astronomy.  Excerpt: On Jan. 2, the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, announced the  discovery of an unusual asteroid , designated 2018 CN41. First identified and submitted by a citizen scientist, the object’s orbit ...came less than 150,000 miles (240,000 km) from Earth, closer than the orbit of the Moon. That qualified it as a near-Earth object (NEO) — one worth monitoring for its potential to someday slam into Earth. But less than 17 hours later, the Minor Planet Center (MPC) issued an  editorial notice : It was deleting 2018 CN41 from its records because, it turned out, the object was not an asteroid. It was a car. To be precise, it was  Elon Musk’s Tesla Roadster  mounted to a Falcon Heavy upper stage, which boosted into orbit around the Sun on Feb. 6, 2018....  Full article at https://www.astronomy.com/science/astronomers-just-deleted-an-asteroid-because-it-turned-out-...
Read more