Re: A partial black hole?

On 2008-02-29, Erik Max Francis <max@[EMAIL PROTECTED]
> wrote:
> Kerr (rotating) black holes have ring-shaped singularities.  I've
> never heard any claim from physicists that the singularity was
> unstable.

From what I have read, the inner Cauchy horizon of the Kerr black hole
is expected to evolve from any small perturbation into a null
singularity with unbounded energy-momentum density.  This is similar
to the Reissner-Nordstrom black hole for which the perturbations have
been analytically studied.

It is likely that no timelike ring singularity would ever form, and
the physical meaning of such a singularity is anyway doubtful.  For
one thing it is free to radiate, and for another the gravitational
field near it is mostly repulsive rather than attractive.

Even Kerr himself does not expect the interior of the Kerr metric to
describe the physical spacetime.  E.g. "What I believe to be more
likely is that the inner event horizon never actually forms", and
"what happens after the outer horizon forms is still a mystery after
more than four decades." (Roy P. Kerr, "Discovering the Kerr and
Kerr-Schild metrics", pp.24-25, at http://arxiv.org/abs/0706.1109v2)


- Tim