Don't put that there!

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Planet X'd in the Face

Space collisions occur all the time in our universe. Particles slam into each other and eventually form planets, moons and stars. Meanwhile, astronomers have observed galaxies in the midst of colossal, head-on smashups. So, can planets collide? Certainly. Will Earth crash into a mysterious Planet X on Dec. 21, 2012? Well, you can choose to believe either conspiracy Web sites or NASA.

The conspiracy theorists arrive at this cataclysmic conclusion based on a few highly dubious sources, but mainly seem to depend on an outdated astronomical discrepancy. For much of the 20th century, differences in the orbits of Uranus and Neptune led some astronomers to suspect an undiscovered planet in the solar system's midst. In reality, they were merely overestimating Neptune's mass, but it caused many people to theorize the existence of Planet X.

According to NASA, anything you read online about Planet X, or Nibiru, smacking into Earth is pure nonsense. So really, don't lose any sleep over this one.

How to Prepare: Planetary collisions aren't generally the sort of thing you bounce back from, so the best you can hope for is to spend your final moments in a comfortable pair of shoes. In fact, FEMA suggests keeping a comfortable pair of walking shoes at work so that in the event of an emergency evacuation, you won't have to hoof it in a pair of painful loafers.

What's next on the apocalypse buffet? Prepare for the Fifth World Order.