The world will end with our Sun comes to the end of it's life cycle and expands into a red giant stage and consumes the earth. That should be about 5 billion years from now...if you believe the science. As for man and how long he will reign....that's a different matter. He has already lasted far longer than you would expect, applying current anthropological theory, and the truth is no one really understands why he has lasted so long. 2012 is just another turn of the calendar...nothing more.