"Fascinating, Captain."
This is interesting stuff. It's funny, when I was about 14, I saw that documentary called Chariots of the Gods, and ever since (even as a JW), I have felt there is no way we are the only 'intelligent life forms' around. I mean, just because WE can't prove there are other civilizations on other planets in other galaxies, doesn't mean they don't exist.
To me, it is the biggest conceit of humanity; to think that in all the limitless (as far as we know) reaches of space, we are the only life forms. Yes, scientists and academics can pontificate all they want, explaining why this and that isn't possible, but how do we really 'know'? We don't - we only know the science that we have, to date, figured out.
A hundred or so years ago, science had not 'discovered' germs, and the medical profession was not aware of the importance of a sterile environment. Does that mean germs did not exist? No, just that we were ignorant of said existence.
Who knows, maybe we were 'planted' here. The possibilities, just like the universe, are endless. And fascinating.