Taken from
here.
Read the article. All of these reasons seem logical enough as reasons the world would end. Which one seems the most likely to you?
I would have to say that as unlikely as it sounds, the Strange Matter theory does hold a place in my mind. Seriouly, EVERYTHING turns into it? That just creeps the shit out of me. It's even more surprising that we have the technology to fuck up like that (Large Hadron Collider, anyone?)
Nanotchnology seems unlikely, because we can counter that somehow. But friggen particles? You can't do fuck about that shit.
The Time Travel theory seems a bit weird too, however much sense it makes.