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Space/Science » in reply to re: Getting straight

re: Getting straight
Greg — (archived)

None of the Martian meteorites found so far have contained Martian life. This can be looked at two ways. One is that there was no life when the meteor was formed, and so there is no danger in MSR. The other is that if there was life there at the time that it doesn't get into meteors, for example that they come from rock that doesn't contain life, or its melted to the point of being undetectible. In that case then meteors could not have seeded Earth with life, and so that can't be used against the dangers of MSR. I recall reading that meteors typically are from rock unlikely to contain life signs anyway.
All the evidence we have seems to point to one of these possibilities, either life doens't ecist there or life can't get here from there. The only other alternative is that meteors in the past acted differently from those today. For example the 4 main impacts on Mars were Utopia, Isidis, Argyre, and Hellas, with possibly an earlier one at Chryse. Schiaparelli is a smaller possibility and from there the impact sizes continue to shrink.
Probably the best candidate for an earlier contamination is from Hellas which was the most recent. Interestingly this might have been about the time the dinosaurs were wiped out, it is even conceivable though very unlikely that that impact came from a piece from Hellas. If so then some case might be made that a contamination occured from Mars then, though we of course don't know if there was life on Mars at the time.

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