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> The weird thing about supermassive black holes is that their average density at the Schwarzschild radius actually goes down as they grow bigger. What does th
by Tommstein 3y ago
> The weird thing about supermassive black holes is that their average density at the Schwarzschild radius actually goes down as they grow bigger.
What does that mean? The Schwarzschild radius is just the distance at which even light can no longer escape, the only matter there is the matter that happens to be falling in at that moment. Unless you mean the average density within the Schwarzschild volume (a term I just made up as far as I know, but you know what I mean) if all the mass of the black hole were spread out evenly throughout it.
- The_Colonel 3y ago> if all the mass of the black hole were spread out evenly throughout it. That seems like a weird condition. "Average density" is pretty well-defined and doesn't need even spreading. Even more, isn't the distribution of mass within a black hole a meaningless question? There's no information coming from the black hole, for an external observer it literally doesn't matter how the matter is arranged within.
- lumost 3y agoThis assumes the mass forms a perfect sphere with no thermal oscillations or other deformities.
- The_Colonel 3y agoWhat claim needs an assumption of being perfectly spherical? A rotating (or merging) black hole can be deformed (non-spherical), but that doesn't stop you to calculate average density.
- lumost 3y agoMy comment was on the the innards of the black hole as a meaningless topic. The event horizon (if observable) is likely to have an immense amount of detail on the geometry and mass distribution inside the event horizon.