I saw the Naked Science special last night about black holes, and one of the scientists said that the idea that compact matter existing inside the blackhole is wrong. The matter exists in a 0 dimensional point = it has been crushed out of existence. So what keeps the black hole going? If the matter in the singularity doesn't exist anymore, why doesn't the spacetime that makes up the black hole simply "flatten" back out? Doesn't a massive object have to exist for the spacetime to bend?