Eventually, probably thousands of years from now, Earth may be hit by an asteroid large enough to wipe everything out. If the planet survives in one piece, life will (if there is enough time) probably start up again. Further into the future than that, million of years from now, the sun will swell up to huge proportions and "swallow" the Earth. If we have survived that long, and not been stupid enough to trash our civilization, we will (well, I THINK we will) have moved on to other planets and started civilizations there. Neither of these things will happen because someone "foretold" it. It will happen because the universe moves according to certain rules of physics and that's the only reason. Anyone, in our current level of technology, who says they know the date and time of the end of the world is full of . . . organic fertilizer.
Well if you read in revelations it tells you about 7 tribulations before the world ends. No body knows if the rapture will come before the 7 year reign tho. The rapture is when all the Christians who have Jesus in their heart go to heaven. I personally can't wait! Heaven will be awesome!!! :)