Tuesday, August 10, 2010

God's Number

Bet you didn't know God had a number. Well, He does, and people have been trying to figure out what it is since 1980.  Confused? Let me explain.

In 1974, the Rubik's Cube was invented.  Most people think of the cube as a brain puzzle, something you play with until you get bored and bury it in the back of a closet or drawer. Mathematicians, however, are fascinated by the puzzle. Solving the cube consists of making a certain number of "moves" to rearrange the squares and the next move always depends on the current position of the squares.  Therefore, an algorithm must exist that can achieve a solved cube.  There are actually many different algorithms that can be memorized by us humans, and most of the require at least 40 moves.  Naturally, given that we are mere mortals, if God went about solving a Rubik's Cube, he would use a much more efficient algorithm than we would.  With the rise of computers that are accessible and affordable, people have been trying to discover exactly how many moves God's algorithm would take to solve a cube.

The estimates for God's Number (the maximum amount of moves God's algorithm would take) have varied throughout the years, with the first guess being 52.  Now, in July 2010, using computer power donated by Google, a group of mathematicians has sorted through all 43,252,003,274,489,856,000 positions of the Rubik's Cube and proven that God's Number is 20.  You can read more about exactly how they did it here, but don't plan on memorizing their formula...as the name suggests - there are so many possibilities, only God could memorize them all.