"Robert Karl Stonjek" wrote in message
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"Greg Neill" wrote in message
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"Robert Karl Stonjek" wrote in message
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If Dark energy exists, then Black Holes must occasionally explode.

Um, why?



An expansion within the Black Hole would cause tremendous heating.

Ummm, there's nothing within a black hole that can expand.

I take
it that matter is compressed as far as it can be compressed during the
formation of a Black hole, and so is no longer compressible. Conversely,
there is no accommodation for asymmetrical expansion anywhere within the
black hole.

There's no normal matter in a black hole. A singularity is
not just really tightly packed matter --- there are no
individual components or bits --- it's crushed essentially
out of existence, down to a mathematical point.


Thus if dark energy were to act in such a way as to cause expansion of any
magnitude at all, the entire surface of the black hole would be disrupted,
perturbed - and don't black holes spin with unbelievable momentum?

Black holes have no surface. Yes, they can have large amounts
of angular momentum, but this is not necessarily always the
case.


The other consideration is the nature of dark energy - doesn't it have the
effect of reversing gravity? Wouldn't the force exerted by dark energy be
equal and opposite to the gravitational force in a particular area of space?
Thus for our black hole, any dark energy would cause an incredible Big
Bang-like expansion.

Dark energy reverses gravity about the same way that bouyancy
does. In other words, it doesn't do anything to gravity itself
but rather adds another force into the mix. There's no reason
for dark energy, which operates over vast intergalactic scales,
to provide an equal and opposite force to gravity over the
tiny local scale of a black hole. If it did, the solar system
would have been sundered and scattered long ago.