I think the panspermia idea is fascinating, but I doubt it is true.
First, even if true, it doesn't explain the origin of life on the alien planet. All it does is change the physical location of the unknown occurrence. You still have to address the question "OK, if life on earth came from microbes on a planet in the Milky Way that were transported to earth on an asteroid, then how did the microbial life get started on the alien planet"?
The odds of life being spontaneously created on the alien planet would STILL be about 1 in X, where X is a number with 40,000 zeros behind it. But then, that planet gets blown apart and the microbes on the asteroid would somehow have to survive for millions of years drifting in the ice-cold vacuum of space with no oxygen and then surviving the blast of heat when it collided with the earth's atmosphere. Those odds are probably just as small as life being crated in the first place.
Originally Posted by ExNYer
I agree with the idea that the odds of life spontaneously forming elsewhere would be the same as here. Unless there is some other place in the universe where conditions are more conducive. Clearly, I have no idea where that might be. Nor does anyone else for that matter. It is truly a fascinating subject.
As for the idea of organisms surviving the coldness of space, remember that after the emergence of life on the planet, earth went through the period geologists refer to as "snowball earth" so it is possible.
It's more of the same old story. The more we know the less we know.
I'm sure it's been said in this thread already but the plain truth is that science can tell us how but not why in many cases.
Einstein said that "Science without God is lame and God without science is blind."
Sums it up nicely for me.