Since we don't have a great idea how life originated, preferring Earth to these small bodies seems to me to be mere prejudice. This is especially the case when early Venus and Mars were likely more habitable than early Earth.
It wouldn't be necessary for a life bearing asteroid to hit Earth in order to seed Earth. Rather, a collision of a life-bearing asteroid (perhaps since frozen) in space would create a large number of fragments, any one of which could seed Earth. This strikes me as the most certain part of the scenario. After all, this is how meteorites are created.
preferring Earth to these small bodies seems to me to be mere prejudice.
I really don't think it is. For any favorable condition you might find in asteroids, early planets can probably match it, and a bunch of other possible conditions besides, with the additional benefit of not requiring a stage where the nascent life has to survive an impact at orbital speeds, subsequent flight through cold irradiated vacuum, and then re-entry through a dense planetary atmosphere. I'm not saying it's impossible, but I'm saying it needs a lot more evidence to take it seriously.
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Since we don't have a great idea how life originated, preferring Earth to these small bodies seems to me to be mere prejudice. This is especially the case when early Venus and Mars were likely more habitable than early Earth.
It wouldn't be necessary for a life bearing asteroid to hit Earth in order to seed Earth. Rather, a collision of a life-bearing asteroid (perhaps since frozen) in space would create a large number of fragments, any one of which could seed Earth. This strikes me as the most certain part of the scenario. After all, this is how meteorites are created.
I really don't think it is. For any favorable condition you might find in asteroids, early planets can probably match it, and a bunch of other possible conditions besides, with the additional benefit of not requiring a stage where the nascent life has to survive an impact at orbital speeds, subsequent flight through cold irradiated vacuum, and then re-entry through a dense planetary atmosphere. I'm not saying it's impossible, but I'm saying it needs a lot more evidence to take it seriously.