Hypervelocity Impact Experiments in the Laboratory Relating to Lunar Astrobiology |
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| Authors: | M J Burchell J Parnell S A Bowden I A Crawford |
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| Institution: | (1) School of Physical Sciences, University of Kent, Canterbury, Kent, CT2 7NH, UK;(2) School of Geosciences, University of Aberdeen, Aberdeen, AB24 3UE, UK;(3) Department of Earth and Planetary Sciences, Birkbeck College London, Malet Street, London, WC1E 7HX, UK |
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| Abstract: | The results of a set of laboratory impact experiments (speeds in the range 1–5 km s−1) are reviewed. They are discussed in the context of terrestrial impact ejecta impacting the Moon and hence lunar astrobiology
through using the Moon to learn about the history of life on Earth. A review of recent results indicates that survival of
quite complex organic molecules can be expected in terrestrial meteorites impacting the lunar surface, but they may have undergone
selective thermal processing both during ejection from the Earth and during lunar impact. Depending on the conditions of the
lunar impact (speed, angle of impact etc.) the shock pressures generated can cause significant but not complete sterilisation
of any microbial load on a meteorite (e.g. at a few GPa 1–0.1% of the microbial load can survive, but at 20 GPa this falls
to typically 0.01–0.001%). For more sophisticated biological products such as seeds (trapped in rocks) the lunar impact speeds
generate shock pressures that disrupt the seeds (experiments show this occurs at approximately 1 GPa or semi-equivalently
1 km s−1). Overall, the delivery of terrestrial material of astrobiological interest to the Moon is supported by these experiments,
although its long term survival on the Moon is a separate issue not discussed here. |
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