I don't believe in it either, if there were aliens they wouldn't come to our planet just to disappear a few seconds later. They would either kill us and get it over with, or organise a meeting with the worlds leaders and say "we come in peace". And if there is life out there I don't think its the big, disgusting, man- eating monsters hollywood has made us to believe, I think it would be like a small plant or insect. (bit anti- climactic, huh?)