ColonelHardisson
What? Me Worry?
I have to admit, I'm not really getting the folks who don't like "a billion".
Same here. As some of those same people point out, we've come this far in only a few tens of thousands. Who knows what will happen in an even greater, geometrically greater, amount of time? Maybe the human race will branch off and each branch develop or regress independently. Maybe some will evolve beyond the need for physical bodies, maybe some will choose to return to human form. I could see us engineering on a planetary scale in a century or two; a billion years may see galactic-scale engineering like in Carl Sagan's book, Contact. Maybe some branch of mankind's descendants preserved the home system for nostalgia's sake. It seems strange to me that people can see us go from animal power to nuclear fission in less then a century, but think it's too optimistic that humans or their descendants could be moving planets and rejuvenating stars in a billion years. Sure, the Sun may burn out or the Earth die or Saturn lose its rings in a billion years...if we let them. Maybe some Vorlon-like descendant of ours will make it his pet project to bring the old homestead back to life.