
Personally, I think the sun will simply grow to an enormous size and die like some other stars in the sky and earth will either be engulfed by the sun or it would become too hot for anything to survive. That is not my only theory though, the same thing that wiped out the dinosaurs could happen to us as well. A huge meteor could strike the earth causing and a vast majority of the earth's volcanoes to erupt causing lava to engulf the earth killing all life as we know it. This is what i think however and if you agree than god for you but if you do not then well believe what you want. Computers will rise up or a solar flare will hit the earth could be what you believe but if i remember right, in Terminator and Knowing, don't we usually have someone stopping it or surviving it in the end?