I’'m a molecular biologist, so this is tangentially related to my field. I think there’s even odds life originated on mars then hopped to earth. NASA has been laying the ground work for a sample return mission for a while now to prove this one way or the other, but apparently the evidence has been mounting for decades.

It’ll be pretty easy to tell once they get some uncontaminated mars rocks. While a lot of life works the way it does because it has to or because it’s optimal for evolution, there’s no accounting for chirality in amino acids (though amino acids in general are arguably inevitable) and nucleic acids are also probably unique to our form of life – at least I haven’t heard or thought of a reason nucleic acids specifically (not some other folding semi-dimer molecule) would be inevitable. There’s also certain amino acid side chains that seem unlikely to be shared; though, unshared side chains would mean little.

It’d actually be a bit sad if life originated on mars as people would suddenly be a lot more interested in searching the stars for life, but the chances of finding it would dramatically drop as a single panspermia event would strongly suggest that complex life requires much more time to evolve than most planets have as a habitable lifespan. I suppose an optimist could argue that humanity is early and/or lucky.

Someone fucked that rock?

That chemical elements were fused in stars?

Nothing?