It should be noted that even if the Mayan calendar or Nibiru doesn't get us, there's still plenty to be worried about. Have you heard of the The Big Rip? It's the point in time when the universe has expanded so much that it tears itself asunder and anything caught in the riff will blink out of existence!

Still not convinced? Well then, how about The Big Freeze or The Big Bounce or The Big Crunch? There's no way to know the Ultimate Fate of the Universe but it sure is fun theorizing, right?