(PhysOrg.com) -- Did the early universe have just one spatial dimension? That
(PhysOrg.com) -- Several speculative theories in physics involve extra dimensions beyond our well-known four (which are broken down into three dimensions of space and one of time). Some theories have suggested 5, 10, 26, or more, with the extra spatial dimensions "hiding" within our observable three dimensions. One thing that all of these extra dimensions have in common is that none has ever been experimentally detected; they are all mathematical predictions.
