A5043031191- Astro and Planetary Science
- Planetary Science and Exploration
- Geology and Paleoclimatology Research
- Space Exploration and Technology
- Space Science and Extraterrestrial Life
- Geological and Geochemical Analysis
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- High-Velocity Impact and Material Behavior
- Spacecraft and Cryogenic Technologies
- earthquake and tectonic studies
- Geomagnetism and Paleomagnetism Studies
- Methane Hydrates and Related Phenomena
- Computational Fluid Dynamics and Aerodynamics
- Marine and environmental studies
- Spaceflight effects on biology
- Fluid Dynamics Simulations and Interactions
- Solar and Space Plasma Dynamics
- Geological formations and processes
- Landslides and related hazards
- Hydrocarbon exploration and reservoir analysis
- Scientific Research and Discoveries
- Stellar, planetary, and galactic studies
- Gas Dynamics and Kinetic Theory
- Plasma and Flow Control in Aerodynamics
Purdue University West Lafayette
2015-2024
Planetary Science Institute
2023
ORCID
2021
University of Arizona
1983-2007
State University of New York
1980
Stony Brook University
1980
HRL Laboratories (United States)
1969
Spectral modeling of the large infrared excess in Spitzer IRS spectra HD 172555 suggests that there is more than 10^19 kg sub-micron dust system. Using physical arguments and constraints from observations, we rule out possibility being created by a magma ocean planet or circumplanetary disk torus. We show consistent with circumstellar debris torus, located at approximately 6 AU, was planetary scale hypervelocity impact. find radiation pressure should remove submicron less one year. However,...
Research Article| February 01, 2012 The Impact-Cratering Process Gareth S. Collins; Collins 1Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, United KingdomE-mail: g.collins@imperial.ac.uk Search for other works by this author on: GSW Google Scholar H. Jay Melosh; Melosh 2Department Atmospheric Sciences, Purdue University, West Lafayette, IN 47907, USAE-mail: jmelosh@purdue.edu Gordon R. Osinski 3Depts. Sciences Physics & Astronomy, University Western Ontario,...
Abstract Intact lunar lava tubes offer a pristine environment to conduct scientific examination of the Moon's composition and potentially serve as secure shelters for humans instruments. We investigated SELENE Lunar Radar Sounder (LRS) data at locations close Marius Hills Hole (MHH), skylight leading an intact tube, found distinctive echo pattern exhibiting precipitous decrease in power, subsequently followed by large second peak that may be evidence existence tube. The search area was...
Abstract NASA's GRAIL mission employed twin spacecraft in polar orbits around the Moon to measure lunar gravity field at unprecedentedly high accuracy and resolution. The low altitude extended enables detection of small‐scale surface or subsurface features. We analyzed these data for evidence empty lava tubes beneath maria. developed two methods, gradiometry cross correlation, isolate target signal long, narrow, sinuous mass deficits from a host other features present data. Here we report...
Models are proposed to account for the formation of slump terraces, central peaks, peak rings, and concentric rings in large impact structures. Crater slumping is attributed process acoustic fluidization, which endows a volume target surrounding crater with Bingham plastic rheology short time after impact. The parameters this model remarkably constant throughout solar system yield stress ranges from maximum 80 bars on Mercury minimum 7 Callisto. viscosity between 10 9 P at onset all bodies...
On the origin of Orientale basin is a major impact crater on Moon, which hard to see from Earth because it right western edge lunar nearside. Relatively undisturbed by later events, serves as prototype for understanding large craters throughout solar system. Zuber et al. used Gravity Recovery and Interior Laboratory (GRAIL) mission map gravitational field around in great detail flying twin spacecraft little 2 km above surface. Johnson performed sophisticated computer simulation its...
Abstract The megaregolith of the Moon is upper region crust, which has been extensively fractured by intense impact bombardment. Little known about formation and evolution lunar megaregolith. Here we implement Grady‐Kipp model for dynamic fragmentation into iSALE shock physics code. This implementation allows us to directly simulate tensile in situ crust. We find that fragment sizes are weakly dependent on impactor size velocity. For impactors 1 km diameter or smaller, a hemispherical zone...
Abstract Major impact events have shaped the Earth as we know it. The Late Heavy Bombardment is of particular interest because it immediately precedes first evidence life. reentry ejecta creates numerous chemical by‐products, including biotic precursors such HCN. This work examines production HCN during in more detail. We stochastically simulate range impacts on early and use models developed from existing studies to predict corresponding properties. Using multiphase flow methods finite‐rate...
Abstract The South Pole‐Aitken basin is a gigantic impact structure on the far side of Moon, with an inner rim extending approximately 2,000 km in long axis dimension. and history this are illuminated by gravity topography data, which constrain subsurface distribution mass. These data point to existence large excess mass Moon's mantle under basin. This anomaly has minimum 2.18 × 10 18 kg likely extends depths more than 300 km. Plausible sources for include metal from core differentiated...
Abstract The impact of asteroids and comets with planetary surfaces is one the most catastrophic, yet ubiquitous, geological processes in solar system. Chicxulub event, which has been linked to Cretaceous-Paleogene (K-Pg) mass extinction marking beginning Cenozoic Era, arguably significant singular event past 100 million years Earth’s history. occurred a marine setting. How quickly seawater re-entered newly formed basin after impact, its effects it on cratering process, remain debated. Here,...
Abstract Double ridges are sprawling features observed globally across the icy surface of Europa. They consist two topographic highs flanking a trough. The relief is approximately 100 m, and extend up to hundreds kilometers in length. interior structure dynamics Europa's ice shell currently poorly constrained. Therefore, accurate models for formation these prominent can be useful determining how operates. We hypothesize that double form as result incremental wedging. use both analytical...