A5083776988- Astro and Planetary Science
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Geology and Paleoclimatology Research
- Geological and Geochemical Analysis
- Space Exploration and Technology
- High-pressure geophysics and materials
- Stellar, planetary, and galactic studies
- Spacecraft and Cryogenic Technologies
- Methane Hydrates and Related Phenomena
- Space Science and Extraterrestrial Life
- Space Satellite Systems and Control
- Geophysics and Gravity Measurements
- Astrophysics and Star Formation Studies
- Isotope Analysis in Ecology
- earthquake and tectonic studies
- Solar and Space Plasma Dynamics
- Paleontology and Stratigraphy of Fossils
- Marine and environmental studies
- Hydrocarbon exploration and reservoir analysis
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
- Atmospheric Ozone and Climate
- Spacecraft Design and Technology
- History and Developments in Astronomy
University of California, Santa Cruz
2016-2025
Planetary Science Institute
2008-2022
Jet Propulsion Laboratory
2021
Peking University
2018
Southwest Research Institute
2016
Johns Hopkins University Applied Physics Laboratory
2016
Charles River Laboratories (Netherlands)
2015
Zero to Three
2014
John Wiley & Sons (United States)
2014
University of California System
2014
High-resolution gravity data obtained from the dual Gravity Recovery and Interior Laboratory (GRAIL) spacecraft show that bulk density of Moon's highlands crust is 2550 kilograms per cubic meter, substantially lower than generally assumed. When combined with remote sensing sample data, this implies an average crustal porosity 12% to depths at least a few kilometers. Lateral variations in correlate largest impact basins, whereas lateral composition. The low-bulk allows construction global...
New Horizons' views of Pluto The flyby and its moon Charon by the Horizons spacecraft generated news coverage around world. Now Stern et al. report first scientific results from high-speed encounter. surface is surprisingly diverse, with large regions differing brightness composition. There ample evidence for ongoing rich geological processes that act to sculpt surface. Charon's similarly complex, numerous relief structures varied coloration. Pluto's atmosphere extensive but less dense than...
In November and December 2012, the Hubble Space Telescope (HST) imaged Europa's ultraviolet emissions in search for vapor plume activity. We report statistically significant coincident surpluses of hydrogen Lyman-α oxygen OI 130.4-nanometer above southern hemisphere 2012. These were persistently found same area over 7 hours observation, suggesting atmospheric inhomogeneity; they are consistent with two 200-km-high plumes water line-of-sight column densities about 10(20) per square meter....
Inside Enceladus Saturn's moon has often been the focus of flybys Cassini spacecraft. Although small—Enceladus is roughly 10 times smaller than largest moon, Titan—Enceladus shown hints having a complex internal structure rich in liquid water. Iess et al. (p. 78 ) used long-range data collected by spacecraft to construct gravity model Enceladus. The resulting field indicates presence large mass anomaly at its south pole. Calculations moment inertia and hydrostatic equilibrium from suggest...
In order to test planetary accretion and differentiation scenarios, we integrated a multistage core-mantle model with N-body simulations. Impacts between embryos planetesimals result in magma ocean formation episodes of core formation. The combines rigorous chemical mass balance metal-silicate element partitioning data. primary constraint on the combined is composition Earth's primitive mantle, Martian fractions metallic cores Earth Mars. refined by least squares minimization up five fitting...
New Horizons unveils the Pluto system In July 2015, spacecraft flew through at high speed, humanity's first close look this enigmatic on outskirts of our solar system. a series papers, team present their analysis encounter data downloaded so far: Moore et al. complex surface features and geology its large moon Charon, including evidence tectonics, glacial flow, possible cryovolcanoes. Grundy analyzed colors chemical compositions surfaces, with ices H 2 O, CH 4 , CO, N NH 3 reddish material...
Unlocking Earth's ancient magnetic past The field protects surface from deadly cosmic radiation and provides clues about the planet's interior. Tarduno et al. found that some of oldest minerals on Earth, Jack Hills zircons, preserved a record over 4 billion years ago (see Perspective by Aubert). appears to have been fully operational mere few hundred million after planet formed. This suggests an early start for plate tectonics shield was important habitability Science , this issue p. 521 ; see also
The Gravity Recovery and Interior Laboratory (GRAIL) mission has sampled lunar gravity with unprecedented accuracy resolution.The GM, the product of gravitational constant G mass M, is very well determined.However, uncertainties in mean density, 3345.56 ± 0.40 kg/m 3 , are limited by G. Values spherical harmonic degree-2 coefficients J 2 C 22 as Love number k describing elastic response to tidal forces, come from two independent analyses month GRAIL Primary Mission data at Jet Propulsion...
Observations from the Gravity Recovery and Interior Laboratory (GRAIL) mission indicate a marked change in gravitational signature of lunar impact structures at morphological transition, with increasing diameter, complex craters to peak-ring basins. At crater diameters larger than ~200 km, central positive Bouguer anomaly is seen within innermost peak ring, an annular negative extends outward this ring outer topographic rim crest. These observations demonstrate that basin-forming impacts...
Abstract Many outer solar system bodies are thought to harbor liquid water oceans beneath their ice shells. This article first reviews how such detected. We then discuss they maintained, when formed, and what the oceans' likely characteristics are. focus in particular on Europa, Ganymede, Callisto, Titan, Enceladus, for which there is direct evidence of subsurface oceans. also consider candidate ocean worlds as Pluto Triton.
The isotopic composition of meteorites reveals a fundamental dichotomy between non-carbonaceous (NC) and carbonaceous (CC) meteorites. However, the origin this dichotomy—whether it results from processes within solar protoplanetary disk or is an inherited heterogeneity system's parental molecular cloud—is not known. To evaluate NC–CC dichotomy, we report Ni data for comprehensive set iron meteorites, with special focus on groups that have been analyzed before belong to CC group. new...
Abstract The isotopic dichotomy between non-carbonaceous (NC) and carbonaceous (CC) meteorites indicates that meteorite parent bodies derive from two genetically distinct reservoirs, which presumably were located inside outside the orbit of Jupiter remained isolated each other for first few million years solar system. Here we review discovery NC–CC its implications understanding early history system, including formation Jupiter, dynamics terrestrial planet formation, origin nature Earth’s...
Abstract Analyses of seismic data from the InSight mission have provided first in situ constraints on thickness crust Mars. These crustal are currently limited to beneath lander that is located northern lowlands, and we use gravity topography construct global models satisfy data. consider a range possible mantle core density profiles, densities, low‐density surface layer, possibility lowlands greater than southern highlands. Using preferred three‐layer model crust, average planet found lie...
Abstract The goal of NASA’s Europa Clipper mission is to assess the habitability Jupiter’s moon Europa. After entering Jupiter orbit in 2030, flight system will collect science data while flying past 49 times at typical closest approach distances 25–100 km. mission’s objectives are investigate Europa’s interior (ice shell and ocean), composition, geology; also search for characterize any current activity including possible plumes. be accomplished with a payload consisting remote sensing...
Abstract In order to improve our understanding of the interior structure Saturn's small moon Enceladus, we reanalyze radiometric tracking and onboard imaging data acquired by Cassini spacecraft during close encounters with moon. We compute global shape, gravity field, rotational parameters Enceladus in a reference frame consistent International Astronomical Union's definition, where center Salih crater is located at −5° East longitude. recover quadrupole field J 3 forced libration amplitude...
▪ Abstract The bulk of the ∼50-km-thick Martian crust formed at ∼4.5 Gyr B.P., perhaps from a magma ocean. This is probably basaltic andesite or and enriched in incompatible heat-producing elements. Later additions denser basalt to were volumetrically minor, but resurfaced significant portions Northern hemisphere. A fraction total thickness was magnetized prior 4 with magnetization later selectively removed by large impacts. Early impacts also modified hemispheric contrast crustal (the...
Recent magnetic studies of Mars suggest that (1) it possessed a periodically reversing field for the first ∼500 Myr its existence and (2) plate tectonics may have been operating during this time. On Earth geodynamo is thought to occur because convection in outer core. This paper estimates amount heat Martian core can conduct absence convection. It uses parameterized, variable‐viscosity thermal evolution models show flux increases if planet's surface increased above value required eliminate...