The end of the world is near—December 21, 2012, to be exact—according to theories based on an purported ancient Maya calendar. Scientists, though, are tripping over themselves to deflate the ballooning hype as the new year dawns. (NASA itself recently felt compelled to issue a comprehensive 2012 fact check.)
(Related: "End of World in 2012? Maya 'Doomsday' Calendar Explained.")
In some 2012 doomsday prophecies, the Earth becomes a deathtrap as it undergoes a "pole shift," courtesy of an asteroid impact (illustrated above), a rare alignment with the center of the Milky Way, and/or massive solar radiation destabilizing the inner Earth by heating it.
The planet's crust and mantle will suddenly shift, spinning around Earth's liquid-iron outer core and sending cities crashing into the sea, the story goes. (Interactive: pole shift theories illustrated.)
Princeton University geologist Adam Maloof has extensively studied pole shifts, and tackled this myth in a 2009 National Geographic Channel documentary called 2012: Countdown to Armageddon (video).
Maloof says magnetic evidence in rocks confirms that continents have undergone such drastic rearrangement, but the process took millions of years—slow enough that humanity wouldn't have felt the motion (quick guide to plate tectonics).