It's possible that someone has told this first so sorry if they had. Many of you probably know the parallel-universe or dimensions. So suggesting that the universe is a page of the book is it possible for the other sides ( below and above our universe) is made of anti-matter and the only thing thank link these pages are black holes? Their explosions created quasars and in-turn created our universe today. Their only escape is that quasar like a certain force keeps the matter and anti-matter within the black hole. It could explain why black holes appear to be in the middle of galaxies.This way all matter can be recycle in never ending universes. It takes long periods of time but it could be possible. I'm no expert but maybe