With the vastness of the ether I do believe there must be life of some form elsewhere. However, the distances are so vast, that unless we discover extradimensional travel (like in Heinlein's The Time Tunnel) I think that contact of any kind has to be a very rare event, indeed. Although, over the course of hundreds of thousands of years of cognizant human existence, I believe this may very well have happened once or twice in antiquity. From all my archaeological studies, in my mind, too many signs point toward this possibility to totally ignore. One of the most notable clues the so-called Nasca lines in South America.
I also have a pet theory concerning extraterrestial life concerning the relativity of size. Since size is so relative in the universal sense of things, and so unfathomable, people tend to think in terms of largeness. Look at the size of the planet Jupiter. But what about smallness? What if there are microcosms of undetected galaxies and solar systems out there the size of a single cell, or perhaps even as small as an atom? And what if the most advanced life in the universe inhabits one of these microscopic worlds? Then they could easily be flitting their miniature spacecraft around us all the time, even into and out of our nostrils and ears, completely unsensed or unseen observers...or manipulators. The same could be said for the other relativity of size...what if the entire universe as we perceive it is just a germ on somebody else's laboratory slide?...hmmmm?
