There would be some evidence in space of a space fairing race if that were the case. There is nothing out there but dust and ice. Untill we discover some ancient satelite or other evidence I think theroies of past inteligent life in our solar system can lay at rest.

I don't think so, but at least the idea is creative and different so, props for that.

I would be more inclined to go with a variation of your idea if there were scientific evidence. Then again, the problem with thinking scientifically is we are saying it's not possible based on what we can see, and what we know as fact today. I will not be surprized in the least when we find out the facts we know today change tomorrow, or next week, or next year.

Also have to keeping in mind that most things I learned in school turned out to be completely inaccurate... I guess anything is possible.

And yeah, I think humans would be able to adapt to just about any condition if given a long enough time and given proper resources.

Anyway... humans can and will destroy just about anything given enough time and the right motivation.