Re: Black hole question

From: Anders Sandberg (
Date: Tue Feb 15 2000 - 11:02:06 MST

"Stirling Westrup" <> writes:

> Many interesting things happen when black holes collide (at least
> theoretically). One is that the final resulting black hole has an
> apparant volume less than the sum of the apparant volumes of the two
> colliding holes.

Also, event horizons can slosh around faster than light - they are not
things per se so they are allowed to do it, rather like how the point
where a laser beam lights up a remote wall can move faster than light
when the laser is turned. Awfully irritating, I have learned it
prevents me from travelling through the central hole in a large
artificial doughnut-shaped black hole - it collapses faster than I can
travel through it... :-)

for some images and movies from simulations of black hole collisions.

> As for particles being pulled in two, it wouldn't
> happen. Quantum fluctuations alone would ensure that the particle
> went one way or the other. Then again, in an area of such extreme
> gravitational stress one would expect to see lots of spontaneous
> pair production, one particle of each pair being sucked into each
> hole.

I wonder if the energy dissipation by separating quarks from each
other would be a significant factor in slowing the collision? Most
likely not, I guess.

> Finally, there was an interesting science fiction short story in
> which one researcher was extracting information from micro
> black-holes by colliding them. She was (somehow) intercepting
> infinitely red-shifted photons that were being pulled out of one
> hole and falling into the other, at the exact moment when their
> event horizons touched.

I think it was "That which survives" by David Brin.

Anders Sandberg                                      Towards Ascension!                  
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y

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