# How can two zero-dimensional black hole singularities have different masses? [duplicate]

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(This question is not a duplicate because it is primarily concerned with how different zero dimensional objects/singularities with zero volume, are able to contain differing information on black holes such as their differing masses.) If a non-rotating black hole singularity is a zero dimensional point with zero volume, and if different black holes have different masses, then how can the differing masses be represented by the same singularity? There would seem to be no space to encode any differences at all between black holes of different masses? This would seem to suggest that non-rotating black holes have something larger than a singularity at their cores. Perhaps there is a state of matter with non-infinite density that is denser than a neutron star, or even a theorized quark star. If the "singularity" in a rotating black hole is a ring with zero dimensional thickness, and thus again zero volume, then the question is the same. How are the differences between differing black holes stored in an object of zero volume, differences such as mass and charge. Zero volume seems to preclude the storage of any information since there is no structure in which to store information. Where have I gone wrong in my understanding?

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• Here I thought black holes were simply bigger on the inside. ; ) – candied_orange May 27 at 0:44

## 1 Answer

Do not confuse mass with mass density. Every object has a theoretical center of mass point. Newton's distance between masses in his gravitational equation refers to these points for example. The sun and earth have quite different masses, however if you could compress their mass densities down so that their spatial extensions coincided with the mass points then you would have two mass points each with zero spatial extension but with different masses. Of course neither of these objects has enough mass to allow gravity to compress them down to a single point. Quantum theory and the planck scale also throw a little wrinkle into this reasoning