Here’s what you’ll learn when you read this story:A backward, mirror universe could explain the existence of dark matter. If an anti-universe exists, it would run backward in time, before the Big Bang. Could it be that what we call the Big Bang was the inflection point of an even bigger bounce in progress? Dark matter forms the bulk of the matter in the universe, but we’ve never been able to see it anywhere. But we can measure the physical (not visual) effects of dark matter in things like gravitational waves.