Originally Posted By: Compugeek
Given the many random chances that seem to be necessary for sentient life to develop -- a star that's not too hot or too cold, ... -- I think intelligent life is going to be very, very rare.

The Drake Equation may be of interest - it turns out that "very, very rare" is still a significant number in a galaxy of a few hundred billion stars. And the Fermi Paradox is about the problem that since they _should_ be out there but aren't, why not?

Some possible answers to the Fermi Paradox are scary considering that our present technology is very close to being able to leave considerable evidence of us (robotic probes to distant stars) in a way that B.E.M.s have not.