Re: A partial black hole?

: James Burns <burns.87@[EMAIL PROTECTED]
>
: My original question was a request for some theorem along the
: lines of the "Black holes have no hair" theorem, but it may
: be that my question is too simple for anyone to have
: bothered with such a theorem.
: 
: Let me try one last time to put my question, only now in
: the terms which you three have offered me: Is it provably
: impossible for a light-like or time-like worldline to
: cross from normal spacetime to this "rotated" spacetime
: /and back again/ to normal spacetime? It's looking like
: the answer is, yes, it's provably impossible.

Weeeeeellll yes and no, aiui (and I may not ui adequately).  The "no"
parts I'm aware of I think I mentioned elsethread.  There's the "cosmic
censor****p principle", where "all signularities are decently clothed in an
event horizon".  Apparently, in some situations, that's not exactly true,
though what it really means in terms of *particles* escaping the event
horizon, I'm unsure.  And then there's the concession that information
falling into an event horizon must be retrievable in principle for various
reasons including thermodynamic-like ones, but again, what that means
in terms of actual scenarios for recovering data (or particles) from
inside the event horizon is unclear to me.  And finally, there's Hawking
radiation, which is comeing at it from another point of view altogether.

So.  Yes, a totally hairless event horizon is thought not to be the case
(aiui, and depending on just what counts as "hair").  No, I'm not sure
that any of these loopholes are what you had in mind.

See also http://en.wikipedia.org/wiki/No_hair_theorem
and maybe http://en.wikipedia.org/wiki/Black_hole_information_paradox
and maybe even http://en.wikipedia.org/wiki/****d_singularity
        and/or http://en.wikipedia.org/wiki/Rotating_black_hole
and lots of tempting/interesting references they point to in turn.

FWIW, there's a story in "The McAndrew Chronicles" about the
inadvisable creation of a ****d singularity from a spinning black hole.


Wayne Throop   throopw@[EMAIL PROTECTED]
   http://sheol.org/throopw