https://phys.org/news/2022-04-theoretic ... ation.html
by Ingrid Fadelli , Phys.org
Black holes are regions in space characterized by gravitational fields so intense that no matter or radiation can escape from them. They are solutions to Einstein's field equations, with a point of unphysical infinite density at their center.
Based on the classical theory of general relativity, all the matter that went into forming a black hole ultimately ends up at its center. This specific prediction is known as the "singularity problem."
In one of his seminal works, Stephen Hawking showed that black holes radiate energy and that they slowly disappear. However, his work suggests that the radiation emitted by black holes does not contain all the information about the matter that went into its formation. In astrophysics, this is referred to as the "information loss problem."