Now I may be wrong in my assessment that the suggested solution is true only when M = 0. I haven’t done the whole calculation, since it’s not high on my priority list. The ring singularity isn’t exactly measurable by observers far from the black hole, so I’m really not concerned about its radius. My intuition is that mass does matter in the calculation, because the ring is a real curvature singularity when mass is not zero, but it’s a coordinate singularity when *M* = 0. Again, I may be wrong about this, so I was a bit hasty to say “wrong wrong wrong”.

The mass of the black hole is included in the values for the inner event horizon and the specific angular momentum (a = J/M, if you will remember your GR 101).

The angular velocity parameter determines the size of the ring for a given mass. If the spin is zero, you get a point singularity.

Albert Z

]]>2. This is rather off-topic for the blog post. ]]>

See sci.physics.research (thread on Ring Sing.)

Using Kerr-Schild metric

Circumference of ring sing = (2)/(pi)(angular velocity param.)

I think the ang. vel. param. = (specific ang. momentum)/(inner event horizon^2 + spec. ang. momen.^2). Or: a.v.p. = a/(r+)^2 + a^2

To a first approx., Radius of ring sing. = 1/(pi)^2 (ang. veloc. param.)

For a typical Kerr black hole, R(ring)/R(bh) ~ 0.43, with dependence on “spin”.

No Charge

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