We don’t know. We can only theorize, but can not prove. A theory is an educated guess. So I guess a black hole would be super, super compressed matter to be ejected from the other side of the black hole. Supposedly nothing(energy) is ever lost but transmutes into something else. We are not designed to find all the answers. We can only go so far and then we hit a wall. To think we will know or understand “The theory of Everything” would render us God-Like." If anyone comes up with a better conception please let me know as quickly as possible. I would like to know…up to a point. Peace.