Well, the string theory talks about multiverse, unlike the Big Bang theory. Michio Kaku explains it by comparing it with bubbles. There are many universes. These universes are like bubbles floating around, and when they collide, they form a single bubble- a universe. When a single bubble, universe, separates, it forms two universes. My questions is- What is in between these universes? What is the beginning of these universes? Does that question ask for another big bang? The multiverse big bang? And plus, in the big bang theory too, what's outside the expanding universe? I assume it's dark matter. But how did that come into existence? Bottom line: None of these theories talk about the beginning of everything. Do you have any ideas?