No one knows when the world is going to end, not even scientists. I remember a couple years back there was some sort of atom smasher experiment going on and there was a plausible chance that it would fail and this world would be sucked into a black hole.
This shit comes up every year (remember Y2K?) and it's unfortunate because it actually freaks some people out. I used to freak myself out about it. The world isn't going to end, and for someone to pinpoint that exact day for all of these cataclysmic occurrences they have to be given the Nobel Prize of being an ignorant asshole.
Oh and by the way, the movie 2012 SUCKED.