It's contingent on getting it, of course. Ideally from the planet itself.<p>There will have to be something to test, though; if there is no biological material to test for anything I'm going to have to lean in favor of unknown-but-non-life process for generating the images I've seen so far. If the structures had visible complex structure I'd buy life (clearly a skeleton, no matter how mineralized by fossilization, was not produced by a purely unliving process), but I'm logically concluding they don't have any more than what we can see in the pictures or the scientists would have (correctly) already announced it was life.<p>Small amounts of biological material can't conclusively prove origin from Earth, but might conclusively prove non-terrestrial origin if for instance all the chirality were flipped. (That would both prove biological processes were at work, since randomly created amino acids have random chirality, and that it was non-terrestrial since our entire ecosystem works on only one of the two forms; anything that exclusively used the other would satisfy me as alien.)