Why Does Our Universe Have Three Dimensions?
Why does our universe look the way it does? In particular, why do we only experience three spatial dimensions in our universe, when superstring theory, for instance, claims that there are ten dimensions — nine spatial dimensions and a tenth dimension of time? Japanese scientists think they may have an explanation for how a three-dimensional universe emerged from the original nine dimensions of space. They describe their new supercomputer calculations simulating the birth of our universe in a forthcoming paper in Physical Review Letters.