We don't even know that black holes even exist, it's all a theory based on physics that has been speculated that there must be something in the center of our universe pulling everything together
The theory is based on the movement of stars and planets in the galaxy and has been the only way to describe how it all works, black holes might not even exist, but if they do, then they're one of the things we have the least amount of knowledge about in the entire universe.
There's even a theory that states that white holes exist, white holes being the opposite to black holes where it spews out mass at all directions rather than taking it in.
As of today we only know what is in the center of the universe because of what must be there, not what actually is there. Must being the word emphasized here, because we calculate everything observable first only then to try and theorize what isn't observable, such as black holes.
