End Times Math: The Equation That Predicts May 21 Judgment Day

The May 21 Judgment Day meme is the brainchild of an 89-year-old radio evangelist named Harold Camping. Using a mathematical system of his own creation to interpret obscure prophecies in the Bible, Camping originally predicted that Sept. 6, 1994 would be Judgment Day, or the day of the "Rapture" when Christian believers will ascend to heaven, leaving the rest of humanity to its deservedly dreary fate.

But 1994 came and went relatively uneventfully, and Camping has since reworked his equations in such a way that they now point to a May 21, 2011 Rapture. Once the 200 million true Christians (in Camping's estimation) have been whisked away this coming Saturday, he says hell on Earth will ensue and last for 5 months, until Oct. 21, at which point the world will end. [Infographic: Doomsdays Past & Present]

Here's the gist of Camping's calculation: He believes Christ was crucified on April 1, 33 A.D., exactly 722,500 days before May 21, 2011. That number, 722,500, is the square of 5 x 10 x 17. In Camping's numerological system, 5 represents atonement, 10 means completeness, and seventeen means heaven. "Five times 10 times 17 is telling you a story," Camping said on his Oakland-based talk show, Family Radio, last year. "It's the story from the time Christ made payment for your sins until you're completely saved."

He added, "I tell ya, I just about fell off my chair when I realized that." [End of the World: Top Doomsday Fears]

Over the past few months, Camping's prophecy has gained considerable traction with Christian fundamentalists. Signs, billboards, and volunteer evangelists around the country have helped spread the word.

Christian naysayers point out that, in the gospel of Matthew, Jesus says Judgment Day cannot be foreseen: "Watch therefore, for you know neither the day nor the hour wherein the Son of man comes."

This article was provided by Life's Little Mysteries, a sister site to LiveScience. Follow Natalie Wolchover on Twitter @nattyover.