The universe may have first existed in only one or two dimensions. How are we supposed to understand that? "The thinking goes like this: Shortly after the Big Bang, the Universe possessed only one dimension of space and one dimension of time. It was basically a straight line. As the Universe began to cool, and expanded, this one dimension of space became 'wrapped up' in such a way to create two dimensions of space and one of time—a plane, like a sheet of flat paper. The transition from one to two dimensions of space was calculated by the researchers to occur when the Universe 'cooled' to an energy level of 100 TeV."