Sometimes proof is met by looking at things with a different point of view.
In the bible and other holy books it wouldn't say "Aliens from a different planet came and visited us and they gave us technology"
Of course not they would have no idea what a alien is so they would assume they where gods because of the way they travelled and looked.
Why do gods come from the sky?
Why don't the gods come from inside of trees or flowers.
Just as another poster said "We used to think the world being round was ridiculous" But hey look now we have found out it is round, maybe in 200 years time this theorey might be accepted, but untill then people who beleive this theorey would just have to wait and either get proved wrong or possibly proved right.
But there is no need to continously argue about it, lets just accept it as a possbility.
We could say a distant planet is made of cheese, untill all the planets in the universe have been discovered there might well be a cheese planet..