I have absolutely no doubt whatsoever that life, including intelligent life, exists elsewhere in this galaxy much less in the entire universe. It may very well have visited, even be watching, this insignificant planet located in the boondocks of a wing of a spiral galaxy.

The question is: Why?

A civilization advanced enough to develop an interstellar drive -- and that isn't an easy task (ask any physicist or aerospace engineer) -- would be advanced enough to do any number of other things, including some very unpleasant ones (for us).

Perhaps the Vogan bulldozers are waiting...or "Childhood's End" is correct. I don't have enough evidence to decide.