Now I don't want to sound like some type of a nay sayer, so to I'll make my stand clear. Yes, I believe that there is other life in the universe, and I hope that someday we will come in contact with them. This will likely be by detecting their radio transmissions, or some such as opposed to having a little green man knock on your door one morning and asking for a cup of anti-matter. But I don't believe they have ever visited us. Why? Read on for the first of my objections.
For those of you who have been weaned on a diet of "Close Encounters of the Third Kind", "Independence Day" and various other gems from Hollywood the chances of aliens having visited us are pretty slim, in fact they are essentially non-existant. Why? I knew you ask so I here goes:
"Space, is big. Really big. You just won't believe how vastly hughly mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space."
Douglas Adams (1952-2001)