[ZX12R]

What about the possibility of life being seeded on Earth from a celestial collision?

If I understand your question, I think it would have had to be a collision with something (rogue/life bearing) encountering our solar system.

[wendy1946]

What about the possibility of life being seeded on Earth from a celestial collision?

Any sort of an ancient alien theory as to life getting onto Earth originally just kicks the can a block or two down the road as far as evolution/evoloserism goes. No such theory can answer the mail for the Haldane dilemma or the amounts of time it would actually take for our present biosphere to arise ala Darwin/Gould if that were possible (it isn't).

[numberonepal]

If I understand your question, I think it would have had to be a collision with something (rogue/life bearing) encountering our solar system.

Exactly. See the link to my explanation in post #15 above - Earth: Rock of Ages or Young Planet?