The sun eventually will fuck out on us... one day were all gonna be sitting in our houses, working, or walking in the park, then all of a sudden the tempature will rise greatly... the sky will turn a blinding white, our gravity will reverse itself, the world will have a massive shaking from being pulled out of orbit by the suns gravatational feild, that will feel like an earthquake, and we will all be obliterated in the suns heat.
This will all happen within 5 minutes, and no one will survive. and this could happen any time from now to a million years in the future.