The Galileo mission to Jupiter revealed that Europa is an ocean world. The Galileo magnetometer experiment in particular provided strong evidence for a salty subsurface ocean beneath the ice shell, likely in contact with the rocky core. Within the ice shell and ocean, a number of tectonic and geodynamic processes may operate today or have operated at some point in the past, including solid ice convection, diapirism, subsumption, and interstitial lake formation.
View Article and Find Full Text PDFThe distribution of impact craters on the ejecta of Giordano Bruno, a recent (<10 Ma) 22-km diameter crater within the lunar highlands, exhibits substantial variations. We surveyed craters ≥ 10 m across a 1,323 km area of Giordano Bruno's ejecta and compared the distribution of craters with variations in thermophysical properties derived from the Lunar Reconnaissance Orbiter Diviner instrument. We used Diviner-derived rock abundance and nighttime regolith temperatures along with thermal model-predicted surface temperatures for a diversity of terrains to identify and isolate areas of the ejecta based on thermophysical properties such as bulk density and thermal conductivity.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2018
Water ice may be allowed to accumulate in permanently shaded regions on airless bodies in the inner solar system such as Mercury, the Moon, and Ceres [Watson K, et al. (1961) 66:3033-3045]. Unlike Mercury and Ceres, direct evidence for water ice exposed at the lunar surface has remained elusive.
View Article and Find Full Text PDFWe find that the reflectance of the lunar surface within 5 ° of latitude of the South Pole increases rapidly with decreasing temperature, near ~110K, behavior consistent with the presence of surface water iceThe North polar region does not show this behavior, nor do South polar surfaces at latitudes more than 5° from the pole. This South pole reflectance anomaly persists when analysis is limited to surfaces with slopes less than 10° to eliminate false detection due to the brightening effect of mass wasting, and also when the very bright south polar crater Shackleton is excluded from the analysis. We also find that south polar regions of permanent shadow that have been reported to be generally brighter at 1064 nm do not show anomalous reflectance when their annual maximum surface temperatures are too high to preserve water ice.
View Article and Find Full Text PDFCancer fatalism may impact outcomes, particularly for African American (AA) women with breast cancer (BrCa). We examined the psychometrics of the modified Powe Fatalism Inventory in sample of AA women with BrCa from two studies. Only the predetermination and God's will items satisfy the conditions to be classified as a strong subscale.
View Article and Find Full Text PDFThe intervention Sisters Tell Others and Revive Yourself (STORY) is a teleconference intervention for African-American women with breast cancer that was studied with a randomized, non-blinded, intention-to-treat trial between 2006 and 2010 in the southeastern United States. This secondary data analysis research measured the impact of STORY on depression and fatigue in African-American women (N = 168) with breast cancer. The were no significant differences in depression or fatigue found between the intervention and control groups based on the Wilcoxon signed-rank test.
View Article and Find Full Text PDFLunar swirls are high-albedo markings on the Moon that occur in both mare and highland terrains; their origin remains a point of contention. Here, we use data from the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer to support the hypothesis that the swirls are formed as a result of deflection of the solar wind by local magnetic fields. Thermal infrared data from this instrument display an anomaly in the position of the silicate Christiansen Feature consistent with reduced space weathering.
View Article and Find Full Text PDFDiviner Lunar Radiometer Experiment surface-temperature maps reveal the existence of widespread surface and near-surface cryogenic regions that extend beyond the boundaries of persistent shadow. The Lunar Crater Observation and Sensing Satellite (LCROSS) struck one of the coldest of these regions, where subsurface temperatures are estimated to be 38 kelvin. Large areas of the lunar polar regions are currently cold enough to cold-trap water ice as well as a range of both more volatile and less volatile species.
View Article and Find Full Text PDFThe Lunar Reconnaissance Orbiter (LRO) Diviner instrument detected a thermal emission signature 90 seconds after the Lunar Crater Observation and Sensing Satellite (LCROSS) Centaur impact and on two subsequent orbits. The impact heated a region of 30 to 200 square meters to at least 950 kelvin, providing a sustained heat source for the sublimation of up to ~300 kilograms of water ice during the 4 minutes of LCROSS post-impact observations. Diviner visible observations constrain the mass of the sunlit ejecta column to be ~10(-6) to 10(-5) kilograms per square meter, which is consistent with LCROSS estimates used to derive the relative abundance of the ice within the regolith.
View Article and Find Full Text PDFWe obtained direct global measurements of the lunar surface using multispectral thermal emission mapping with the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment. Most lunar terrains have spectral signatures that are consistent with known lunar anorthosite and basalt compositions. However, the data have also revealed the presence of highly evolved, silica-rich lunar soils in kilometer-scale and larger exposures, expanded the compositional range of the anorthosites that dominate the lunar crust, and shown that pristine lunar mantle is not exposed at the lunar surface at the kilometer scale.
View Article and Find Full Text PDFComparison was made of the seed production of two species of burdock, Arctium minus (Hill) Bernh. and A. lappa L.
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