Anyone who watches Star Trek knows that the universe has more than four dimensions (3 of space, 1 of time). Spaceships are always whisking off into hyperspace. But can we prove that more than three spatial dimensions exist?

Shu-Yuan Chu, University of California at Riverside, has shown theoretically that in a five-dimensional world (4 of space, 1 of time) electric charge need not be conserved. This opens up an experimental avenue to test for an extra spatial dimension.

For background, recall that physicists originally maintained that mass and energy had to be conserved separately. Then, Einstein came along to show that mass and energy could be interchanged, via E = mc^{2} , but that they had to be conserved together. In Shu-Yuan Chu's five-dimensional universe mass and charge can be interchanged, but their sum must be conserved. In other words, there exists an E = mc^{2} equivalent for mass and charge in five dimensions. We could look for this extra spatial dimension by looking for a particle that can be converted into another particle with the same mass + charge, but made up of a different combination of mass and charge. If such reactions exist, we may be able to explore hyperspace in fact rather than in science fiction.

(Gribbin, John; "Can Electric Charge Be Destroyed?" New Scientist, p. 16, October 5,1994.)