Hell fires, endless winters, or a planet wracked by earthquakes are a few versions of Armageddon visualized by the Vikings, Aztecs, and the rest of our ancient ancestors. But which does modern science think will be closest to the truth? Celestial phenomena--the aging of our sun, the expansion of our universe, and other potentially cataclysmic events--could trigger the kind of Armageddon the ancients feared. Which ancient prophecy do scientists believe actually foretells our doom? And how close are we to the end of the world?