Babylon 5 put it best... (Score 5, Interesting)

"No. We have to stay here [Babylon 5] and there's a simple reason why. Ask ten different scientists about the environment, population control, genetics and you'll get ten different answers, but there's one thing every scientist on the planet agrees on. Whether it happens in a hundred years or a thousand years or a million years, eventually our Sun will grow cold and go out. When that happens, it won't just take us. It'll take Marilyn Monroe and Lao-Tzu, Einstein, Morobuto, Buddy Holly, Aristophanes .. and all of this .. all of this was for nothing unless we go to the stars." (Infection, season 1, ep. 4)

Sappy, yeah. But it makes the point nicely.

(quote copied from http://jdmoncada.tripod.com/babylon5.html)