A series of viral articles claimed that NASA had discovered particles from another parallel universe in which time runs backward. These claims were incorrect. The true story is far more exciting and strange, involving a journey into the Big Bang and out the other side.
The sensational headlines had muddled the findings of an obscure 2018 paper, never published in a peer-reviewed journal, which argued that our universe might have a mirror reflection across time, a partner universe that stretches beyond the Big Bang. If that’s the case, and a series of other extremely unlikely and outlandish hypotheses turn out to be true, the paper argued, then that in turn could explain a mysterious signal hinting that a completely new particle is flying out of the ice in Antarctica.
The claim that NASA discovered a parallel universe seemed to have been first dreamed up by British tabloid The Daily Star, and the story was then picked up by British and American outlets, including The New York Post.