So in a way, this is time travel. If you wanted to see what the world looks like in five thousand years, you could get on a spaceship, accelerate way out to whe

So in a way, this is time travel. If you wanted to see what the world looks like in five thousand years, you could get on a spaceship, accelerate way out to wherever and back, and voila! you've fast-forwarded five millennia. A fascinating thought. The ship and crew would surely be long forgotten. You may be greeted as an alien visitor, until the people of that time recognize your relatively ancient technology from fragments of historical records. Too bad you speak a language nobody else even remembers. Or perhaps you emerge as gods on a pillar of fire from the sky, witnessed by the primitive-again survivors of whatever has played out since you left. I'm strangely tempted. If you offer me a ticket on such a ship, I might just come along.