إضافة تسمية توضيحية Illustration courtesy Nicolle Rager-Fuller, NSF 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.) Princeto...