Your second sentance is irrelevant, it's not like every living thing on earth is believed to go to heaven.
1) They can't be absolved of their sins, since Jesus didn't die for them.
2) The Earthly Jesus died for all sentient beings across the universe, but the fact that he did so on Earth demonstrates that Earthlings have a special place in God's creation (also, note that the Old Testament Jews were God's chosen people).
In a religious context, no good can come of this.
3) Extraterrestrials did not necessarily experience The Fall, and therefor have no need of a savior.
I'm not aware of Lewis's argument, but I did think about this. It seems to me that we'd be able to determine this by simple inspection.
I assume that when we met these aliens, we'll be able to observe that they are sinful creatures: they will lie, steal, murder, etc., just like we do. This being the case, they'll need some mechanism for unloading those sins, won't they?
But: (1) maybe they won't be sinful; or (2) maybe there's some theological point that makes "The Fall" as such pivotal, so that other sins can be freely absolved, so long as one (or one's ancestors) haven't eaten from the tree of knowledge?
EDIT: As already referenced elsewhere in this thread, C.S. Lewis hypothesized -- a search through the thread for "Lewis" shows our interchange, and one other mention that doesn't reference aliens directly, but only the evil that humans could bring to them. And searching for "Fall" shows it nowhere else as a single word. So I think you're unfair in suggesting that my post was redundant.
I suppose people sooner call the aliens soulless demons or rethink their whole religion than go half way in one direction and then stop in the middle.
Also; the existence or lack of existence of any alien life form would have no theological bearing on the western church. (That’s not to say that it would in the east. I just am ignorant of the details -- though if I was a betting man I would say that it is the same in that case also.) Wouldn’t change a thing; and not because it would get “swept under the carpet” but because it really changes nothing core to the dogma deemed necessary for the western church (i.e. the Ecumenical creeds).
And, just as an even further aside, some prominent Christian theologians believe that aliens might exist.
And I think this news is still no proof for skeptical people (like myself). They found molecules that are very rare on earth and are now suggesting they originated in space:
"...but were unsure whether these materials actually originate in space. The presence of these three molecules, however, suggest that they do, potentially raising new questions..."
So just new questions and suggestions. No proof of alien life for me. But interesting!
Sure, an agnostic might be put into a further tailspin, but so what? Most of the world's faithful have already demonstrated the enviable ability to suspend any desire to investigate the mechanics of their belief system. What difference will it matter that aliens were thrown into the equation?