Craters formed by the impact of agglomerated materials are commonly observed in nature, such as asteroids colliding with planets and moons. In this paper, we investigate how the projectile spin and cohesion lead to different crater shapes. For that, we carried out discrete element method computations of spinning granular projectiles impacting onto cohesionless grains for different bonding stresses, initial spins, and initial heights. We found that, as the bonding stresses decrease and the initial spin increases, the projectile's grains spread farther from the collision point, and in consequence, the crater shape becomes flatter, with peaks around the rim and in the center of the crater. Our results shed light on the dispersion of the projectile's material and the different shapes of craters found on Earth and other planetary environments.
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Proc Natl Acad Sci U S A
January 2025
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109.
The NASA Mars 2020 Perseverance Rover Mission has collected samples of rock, regolith, and atmosphere within the Noachian-aged Jezero Crater, once the site of a delta-lake system with a high potential for habitability and biosignature preservation. Between sols 109 and 1,088 of the mission, 27 sample tubes have been sealed, including witness tubes. Each sealed sample tube has been collected along with detailed documentation provided by the Perseverance instrument payload, preserving geological and environmental context.
View Article and Find Full Text PDFJ Geophys Res Planets
December 2024
Institut für Geophysik, ETH Zurich Zurich Switzerland.
Impact cratering is one of the fundamental processes throughout the history of the Solar System. The formation of new impact craters on planetary bodies has been observed with repeat images from orbiting satellites. However, the time gap between images is often large enough to preclude detailed analysis of smaller-scale features such as secondary impact craters, which are often removed or buried over a short time period.
View Article and Find Full Text PDFSci Total Environ
December 2024
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan; Chubu Institute for Advanced Studies, Chubu University, Kasugai, Japan. Electronic address:
There has been much interest about how to identify an ice core signal for oxidizing capacity of the troposphere. This study broadly explains the air-snow transfer/deposition process using ice core records of dicarboxylic (DCAs), ω-oxocarboxylic as well as pyruvic acids and α-dicarbonyls, which are potentially formed by atmospheric oxidation of aromatic hydrocarbons from the continent, incloud-oxidation of isoprene and unsaturated fatty acids from the western North Pacific. An ice core (~152 m long, 304 years) was collected at an ice cap on the Gorshkov crater at the summit of Ushkovsky (56° 04'N, 160° 28'E, altitude: 3903 m) in the Kamchatka Peninsula from southeastern Siberia.
View Article and Find Full Text PDFJ Environ Radioact
December 2024
1 Kiowa Lane, White Rock, NM, 87547, USA.
Glass fragments (16 green glasses and 2 red glasses) were handpicked from crushed Trinitite. X-ray diffraction studies revealed that these samples were essentially pure glass with the exception of minor amounts (less than 4 wt%) of quartz (which acts as a diluent) in some samples. The concentrations of 45 elements in the Trinity glasses were determined using Instrumental Neutron Activation Analysis.
View Article and Find Full Text PDFToxicol Rep
December 2024
Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan.
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