More recent models sometimes involve extra dimensions of space, beyond the three that we know and experience. Within these theories, the forms of matter that we experience are confined to what is known as a brane—a three-dimensional space that is, in reality, a subset of the greater multidimensional space. Our world appears to us to be three-dimensional solely because electrons, photons, and the other known forms of matter can travel only within the brane’s limits. The brane itself, however, can move through the full dimensionality of space. Within this kind of picture, something that looks
...more
