I've written it before and I'll write it again: modern physics is weird.
The universe we live in may not be the only one out there. In fact, our universe could be just one of an infinite number of universes making up a "multiverse."
Though the concept may stretch credulity, there's good physics behind it. And there's not just one way to get to a multiverse— numerous physics theories independently point to such a conclusion. In fact, some experts think the existence ofhidden universes is more likely than not.