Our universe began with a Big Bang some 13-15 billion years ago. On this, most physicists agree. But few theorists have ventured to explain what happened “before” the Big Bang, or how the Big Bang came to be. This is because the laws of physics break down at the point of a singularity, such as with the one that physicists claim composed pre-Big Bang reality.But a few pioneering physicists are now positing a mind-blowing new theory that could forever change our perspective on the beginnings of the universe. Perhaps, they suggest, the entire universe — all the galaxies, stars, planets, everything — exists wholly inside a massive black hole, reports National Geographic.This radical theory would imply that our universe is just one of many. It would suggest that our universe is ultimately contained within a much larger universe — a mother universe, if you will — which harbors the black hole we’re currently living in. It’s a wild theory, but it’s one that is slowly but surely garnering consideration from physicists.