[mojosam]

I don't see how that's an apt analogy. Geocentrism put the Earth at the center of the universe, around which the rest of the universe rotated. But saying life on Earth originated on Earth does not in any way put the Earth at the center of anything. Nor does it in any way mean that Earth is unique.

The bottom line is that -- because we don't know how abiogenesis occurred, whether here or somewhere else -- we have no way to judge how common it is. It could be that, given enough time, life spontaneously forms on any planet or moon that offers a certain set of conditions, and Earth just happens to be one of those planets, meaning it is still not "the center" of anything.

In fact, in the extreme case, panspermia is much more geocentric, saying that life formed in just one very special place -- maybe not the Earth, but somewhere, the "center of life in the universe" -- and then spread by diffusion to all the other locations in which life existed. But that seems like an unlikely and unnecessary model; if life can spontaneously begin somewhere, why should we assume it can't begin in many places, and if that's true, why not also on Earth?

[kyleyeats]

The idea is that it puts Earth at the center of the biological universe.

Generally the idea is that abiogenesis is very rare. I don't think any panspermists are saying that it only happened in one spot. As you pointed out that's basically the same belief as thinking it happened just once on Earth. The two 'versions' (they're not mutually exclusive) I'm familiar with are spreading via waterbears on comets or whatever, and also seeding by intelligent life. I think we have evidence for both in our own solar system, although the life we've seeded probably didn't take hold for very long.