I was sitting in my doctor's office this morning, waiting for a confirmation of my strep throat (which I got), reading the March issue of Scientific American. I learned something there that I did not know. Astronomers living in the very distant future will likely have very different beliefs about the cosmos than we do today.
Apparently, the galaxies and clusters in our local supergroup (which includes the Milky Way and the Andromeda Galaxy) are slowly being drawn together by gravity and will eventually collide to form a supergalaxy. Meanwhile, the galaxies outside this local group are moving away from us at a high rate of speed. (This is, of course, relative -- a resident of one of those galaxies would perceive us as moving away at the same rate.) In, say, 100 billion years, those other galaxies will be imperceptible from Earth. They will have moved too far away, and their radiation signature will have red-shifted, I think, to the point that they are indistinguishable from background radiation. So an astronomer living 100 billion years from now will only know of one giant supergalaxy sitting amidst a cosmic void. They'll truly think that their galaxy is the center of the universe and is the only thing out there. Unless we can preserve some information for them, which I kinda doubt we can do.
Oh, and about 10 trillion years from now, our supergalaxy will collapse into a giant black hole. You don't want to be around then.
Of course, Earth will likely only last another 5 billion years (maybe less if McCain is elected), at which point the sun will burn out. So this is all academic. But I still found it a bit bleak.