Scientists Say There May Be a Mirror Universe in Which Time Runs Backwards

As Live Science reports, a recently published paper by an international team of theoretical physicists is lending credibility to the concept of such an “anti-universe” — a theory which could also help explain the existence of dark matter, a mysterious yet abundant substance filling our universe.

The theory behind the study, set to be published in the journal Annals of Physics, relies on what physicists call the three fundamental symmetries in nature. In the Standard Model of Particle Physics, they are: charge, because flipping the charge of a particle in a given interaction results in an equal and opposite charge; parity, because the mirror image of a particle interaction will look the same as the original; and time, because interactions that run backwards in time look the same as their original.