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Geologic studies of outer solar system satellites: Iapetus and EuropaA model of regolith evolution on bodies subjected to an asymmetric impact flux is presented. The general effect of an asymmetric impact flux is ballistic diffusion of regolith from areas of high impact flux to areas of lower flux. The effect is most pronounced on low gravity bodies where ejecta travel distances are large, and on bodies with strong flux asymmetries. It may be especially important on Iapetus, where retrograde debris from Phoebe striking the leading hemisphere may produce a flux asymmetry as large as 100 to 1 from apex to antapex. We find that the net amount of material transported by ballistic diffusion is inversely proportional to satellite density. Theoretical calculations and Voyager observations support the view that tidal heating is sufficient to maintain a liquid layer throughout the history of Europa. Photosynthetic, thermal, electrical, and chemical energy sources are considered. The calculations suggest that there may be regions on Europa, very limited in space and time, with physical conditions that are within the range of adaptation of life on Earth. Calculations for the electrical currents within Europa for a thick ice crust are very small.
Document ID
19840015380
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Squyres, S. W.
(NASA Ames Research Center Moffett Field, CA, United States)
Reynolds, R. T.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1984
Publication Information
Publication: NASA. Washington Repts. of Planetary Geol. Program
Subject Category
Lunar And Planetary Exploration
Accession Number
84N23448
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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