That said, I do suspect that there may be a core of truth to the idea that our planet was visited by something or someone in the distant past. This comes back to the old "absence of proof is not proof of absence" issue, though.
So, who knows? I don't see any grounds to dismiss the idea out of hand.
"There are known knowns. There are known unknowns and there are unknown unknowns."
Every logician will agree that he forgot the unknown knowns, but that is another story.
"The first thing Fascists usually try to do is silencing the opposition."
