thers also a cool one I saw in nature last year...bascially the reasoning is, if the universe is infinite, or even just incredibly big, which looking at movement of plantes and running off big bang theory we can assume it is (not infinte...jsut big enough) then some incredibly far distance away from here, like ten or twelve times as far as light has every travelled to the earth. so something like 10 billion years away travelling at the speed of light, by mathamatical probablility, if there is uniform elemental composition of the univers, then after that difference there will be a totally parallel universe, perfect to every last detail. why? because in our "univers" there are a finite number of atoms (qirks, quarks etc...), and theres a finite number of ways those atoms can be arranged. therefore, you go far enough, and you will eventually find another palce where all other possible arrangments have been used, and the first one is duplicated. bingo, parallel universe.