Of all the most fantastic things science has predicted, perhaps the most head-spinning is the idea that the universe we live in may not be the only one out there.First proposed by Hugh Everett in 1957, the theory tries to make sense of how to pinpoint the location of particles like electrons, as they appear to be in more than one place at one time. One explanation is that the particles don’t just exist in our universe, they flit into existence in other universes too. And there are an infinite number of these parallel universes, all of them slightly different. In theory, this means there could be a parallel universe in which dinosaurs are not extinct, one in which you were never born, and one in which Elvis Presley is still alive.This many-worlds idea is not universally accepted, but variations on this theme have emerged – the most recent of which was published earlier this month, where Australian and US physicists have proposed that parallel universes not only exist but they also interact with one another, and that this could explain oddities like how particles can exist in two places at the same time.How do particles have the potential to be in more than one place at more than one time? Watch this clip from the BBC programme Parallel Universes to find out more. -BBC
