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The Age of the Surface of VenusImpact craters on Venus appear to be uniformly and randomly scattered over a once, but no longer, geologically active planet. To first approximation, the planet shows a single surface of a single age. Here we use Monte Carlo cratering simulations to estimate the age of the surface of Venus. The simulations are based on the present populations of Earth-approaching asteroids, Jupiter-family, Halley-family, and long period comets; they use standard Schmidt-Housen crater scalings in the gravity regime; and they describe interaction with the atmosphere using a semi-analytic 'pancake' model that is calibrated to detailed numerical simulations of impactors striking Venus. The lunar and terrestrial cratering records are also simulated. Both of these records suffer from poor statistics. The Moon has few young large craters and fewer still whose ages are known, and the record is biased because small craters tend to look old and large craters tend to look young. The craters of the Earth provide the only reliable ages, but these craters are few, eroded, of uncertain diameter, and statistically incomplete. Together the three cratering records can be inverted to constrain the flux of impacting bodies, crater diameters given impact parameters, and the calibration of atmospheric interactions. The surface age of Venus that results is relatively young. Alternatively, we can use our best estimates for these three input parameters to derive a best estimate for the age of the surface of Venus. Our tentative conclusions are that comets are unimportant, that the lunar and terrestrial crater records are both subject to strong biases, that there is no strong evidence for an increasing cratering flux in recent years, and that that the nominal age of the surface of Venus is about 600 Ma, although the uncertainty is about a factor of two. The chief difference between our estimate and earlier, somewhat younger estimates is that we find that the venusian atmosphere is less permeable to impacting bodies than supposed by earlier studies. An older surface increases the likelihood that Venus is dead.
Document ID
20020047558
Acquisition Source
Ames Research Center
Document Type
Other
Authors
Zahnle, K. J.
(NASA Ames Research Center Moffett Field, CA United States)
McKinnon, William B.
(Washington Univ. Saint Louis, MO United States)
Young, Richard E.
Date Acquired
August 20, 2013
Publication Date
January 1, 1997
Subject Category
Lunar And Planetary Science And Exploration
Meeting Information
Meeting: 1997 Chapman Venus Conference
Location: Aspen, CO
Country: United States
Start Date: September 4, 1997
End Date: September 7, 1997
Funding Number(s)
PROJECT: RTOP 344-33-10-18
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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