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by pdonis 1117 days ago
> spinning is an accelerated reference frame

Not necessarily. The three definitions for a "spinning" black hole that I gave upthread do not require the presence of any accelerated frames or observers.

> what does it mean for a black hole, which we assume to be a singularity occupying no space at all

This is not correct. A black hole is a finite region of spacetime enclosed by an event horizon. The singularity is inside the hole but is not all of the hole.

> to be spinning? We don’t know.

Yes, we do. We have known since the 1960s that the Kerr solution to the Einstein Field Equation describes a spinning black hole, and all of the geometric properties of that solution have been known for almost as long as that.

> That’s one of the gaps in our theory.

No, it's not. See above.

> as the collapsed remnants of an object that was spinning, they should have done residual angular momentum.

This is correct, but it does not imply or support your other claims.

1 comments

You're missing the point that none of the three definitions you provided offer a mechanistic explanation.
You're missing the point that, since a black hole is purely made of spacetime geometry, there is no "mechanistic explanation" of its spin in the sense you mean.
You don't know that.