BBC Horizon: Parallel Universes (Part 1)

Some scientists now believe there may really be a parallel universe — in fact, there may be an infinite number of parallel universes, and we just happen to live in one of them. These other universes contain space, time and strange forms of exotic matter. Some of them may even contain you, in a slightly different form. Astonishingly, these parallel universes may exist less than one millimetre away from us and our gravity may just be a weak signal leaking out of another universe into ours.