Scientists these days are exploring all kinds of fascinating ideas, ideas I've found fascinating since first reading about them in new age books many years ago. One of the most fascinating to me is the idea of multiple universes. A sci-fi movie or two has also touched on this idea of multiple universes.
It's just an idea, an idea scientists talks about as a 'multiverse.' There is no proof that other universes besides ours exist, yet scientists can apply laws of physics to the possibility and, at this time anyway, that possibility seems just as likely true as any other possibility they're exploring.
Mindy Weisberger's June 19, 2017 Live Science article (link to article below) nicely overviews the idea along with several versions of how it might work. She describes a multiverse as 'worlds that invisibly coexist alongside us, perhaps representing versions of reality that are near-identical to our own….'
My personal favourite among possible versions of how this might work: quantum universes. Sci-fi movies have explored this idea as have new age books. Think of it as different universes infinitely spreading out to cover all possible lives you might live, if you made different choices at major choice points throughout your life example.