There have been countless theories throughout time about how the world will end.

 

At the turn of the 21st century, the Y2k part of the impending devastation was averted: The dooms day merchants predicted that the new century would bring about total destruction, and no one would survive. Others believe that Earth would enter another Ice age, which will kill off all living things.


According to astronomers, billions of years from now, the Sun will become a red giant, expanding to a size larger than the Earth's orbit and consuming Earth in the process. Even if the planet somehow survives, the sun will eventually shrink, becoming a white dwarf and gradually cooling off until it can no longer warm anything in the solar system.

In 2006, Mel Gibson released a movie about the Mayan civilization. "Apocalypto" follows one man's journey from slavery back to his family. During the course of the movie, a young woman prophesizes that a man will bring an end to the Mayans and wipe out their civilization. But in the real world, it's not a Mayan woman but the Mayan calendar that some speculators believe foretells an apocalyptic event. It even gives us a potential date for the theoretical downfall: Dec. 21,2012.

Scenes from the upcoming film 2012. Courtesy Columbia Pictures.Scenes from the motion picture "2012." Courtesy Columbia Pictures.

Many doomsayers hang onto the idea that this ancient calendar is a ticking time bomb that signals our fast-approaching demise during the winter solstice of 2012. While scholars pay little heed to these fervent forecasts, they're still interested in the calendar. For example, there is some lingering disagreement over which day marks the exact beginning of the Mayan calendar. One commonly referenced date is Aug. 11, 3114 B.C., although other researchers pinpoint dates such as Aug. 13, 3114 B.C. (which would actually shift the big day to Dec. 23).