[Stolpe]

That last point is interesting. Do you have a source on that?

[Symmetry]

Here's an example. The structures inside the meteorite were't proved to be life but if they had been alive they would have survived the trip from Mars to Earth.

http://en.wikipedia.org/wiki/Allan_Hills_84001

[Luc]

That trip took 17 million years according to the Wikipedia article. Seems a bit long for anything to survive, surely?

[danieltillett]

I can't find the original source for this but this does talk about it [1].

1. http://www.nap.edu/openbook.php?record_id=5563&page=17