panspermia

Unless of course the panspermia hypothesis is correct and that is indeed where life on Earth came from.

Whether through panspermia or ab initio, it appears difficult neither for life to get started nor to keep hanging around.

Sounds like you're talking about panspermia, which does seem very likely to me as well.

Expanding on this is the concept of panspermia, life spreading across worlds on its own.

That's fine (although panspermia might have played a role bringing our cells from elsewhere).

Ideal for the first iteration of life and perhaps for an initial panspermia event that seeded all parts of the expanding universe.

Hell, they could be here already; panspermia is still a totally valid theory.

I put it at well under 1%, even if we were to assume that the panspermia hypothesis is true.

First time I heard the idea but it's intriguing, and segues into the whole idea of panspermia.

Finding life on Mars could also lend support to the panspermia hypothesis.

My money's on extraterrestrial origin, aka 'exogenesis', and probably 'panspermia' as well.

On the other hand, assuming panspermia, there's enough of a chance for life to be on Mars given the fact that its neighbor has life.

(This is the theory of "panspermia".) Or, the same collision processes that brought the Martian-meteor with maybe-fossils to Earth, could have carried live spores between the planets – so a single microbial-evolution inside our solar system could reach multiple planets.

Panspermia has nothing to with where the water came from.

Panspermia may well be a much simpler vector.

Panspermia simply defers the origin of life elsewhere and now you have to explain how seeds survived travelling through the hostile environment of space and impacting on Earth, which complicates it quite a bit.