The world will end in 7.5 billion years when our sun, Sol, runs low on fuel and turns into a red giant star whose diameter will be greater than the earth's orbit, thus consuming the entire earth in one little puff of dark smoke.
Oh, there are so many ways. I watch a lot of Discovery and Science channel just to see the reproductions of astronomical phenomena. But one thing I have tried to imagine is what it would be like to look into the night sky and see a huge asteroid with our number on it. Well, not a literal number. It's not that I want this to happen; one of the wonderful things about the universe is how life persists, and I want life here to persist. I just wonder what that would be like, to see that. Somehow, I don't think I would be frightened, just struck dumb with wonder. Long answer for a short question, but I get that way sometimes.