The many worlds interpretation of quantum mechanics is the idea that all possible alternate histories of the universe actually exist. At every point in time, the universe splits into a multitude of existences in which every possible outcome of each quantum process actually happens.
So in this universe you are sitting in front of your computer reading this story, in another you are reading a different story, in yet another you are about to be run over by a truck. In many, you don't exist at all.
This implies that there are an infinite number of universes, or at least a very large number of them.
To read the rest of the article, click here."This new paper by Lenny is deep and I will ponder it in the next few days." Jack Sarfatti 5/23/2011