From: Reilly Jones (Reilly@compuserve.com)
Date: Tue Apr 14 1998 - 12:48:10 MDT
Damien Broderick wrote 4/13/98: <Black holes evaporate when the external
temperature is *lower* than that of the hole, not higher.
This discussion seems wrong-headed anyway, because the canonical view of
Hawking radiation is that it's due to the infall of one half of a virtual
particle pair ripped out of the vacuum beyond the hole, and the slingshot
escape of the other. Positive energy is *not* tunnelling out of the hole,
negative energy is being imported into it. I can imagine that this is the
kind of claim that will set Reilly's teeth on edge...>
There is something here that sets my teeth on edge. Black holes with less
mass evaporate because their temperature is greater than the background
temperature, black holes with more mass accrete because their temperature
is less than the background temperature. Now, when we have a black hole
with sufficient mass to achieve a temperature a hair more than the
background temperature, it is evaporating. As a gedanken experiment, let's
dribble itsy bitsy bits of matter towards this black hole and watch what
happens at the event horizon Planck moment by Planck moment. We are
carefully cooling the black hole until, at a given Planck moment,
equilibrium is reached with the background temperature. At the very next
Planck moment - Poof! - the black hole is now cooler than the background
and begins to accrete even after we immediately turn off the dribble of
matter. In one instant, the black hole turns from an everyday ordinary
melting ice cube into a refrigerator powerful enough to suck in every bit
of matter and energy that drifts by it, to suck in the whole universe if we
could maneuver it into the black hole's vicinity. The only way out of the
eternal mega-refrigerator scenario is to wait for the death-worshipper's
ultimate paradise - the heat death of the universe. I just don't feel
comfortable with this.
The surface of the event horizon in such a scenario seems to me to be quite
complex. Aside from tidal forces of rotation, which breaks the spherical
geometry of the surface and creates complex mixing patterns, there should
be peaks and valleys at the surface due to the underlying distribution of
matter inside the black hole and due to quantum fluctuations. The surface
should be roiling like a flag blowing in the wind. Evaporation would occur
at the peaks from the tangential shear from incoming particles and
accretion would occur in the valleys. I am uncertain of the full nature of
particle interactions in such a scenario, but my intuition says that as the
peaks are sheared away in evaporation, the valleys temporarily are more
open to accretion in a see-saw action. The canonical interpretation says
that the greater the event horizon is relative to the mass inside, the more
peaks control the action and vice versa. But I not sure if the true
dynamics at the surface of larger masses tip the scale to the valleys. I
am not certain that the thickness of the region where particles interact at
the event horizon is constant regardless of the mass of the black hole,
even though this is one of the underlying assumptions of the canonical
interpretation. In any event, thanks for the response.
John Clark wrote 4/14/98: <If you define a vacuum far from any object as
having zero pressure and if the vacuum can still push the plates together
then the space between the plates must have negative pressure. According
to Einstein, mass is not the only thing that can warp space and time, that
is, create gravity, pressure can too, although this only becomes important
when the pressure is VERY high, like inside a Neutron star. New theory
says negative pressure should do interesting things to time and space
also, just like positive pressure, but this part has not been confirmed
experimentally because the effect is so tiny.
An observer's clock between the plates will (probably) run a little fast
and for an observer outside the plates distances would (probably) expand a
little. Since speed is distance divided by time nobody sees a change in
the speed of light. This negative pressure idea is a little similar to the
old cosmological constant idea of Einstein, he later said that was the
worst mistake of his life, but maybe not, it may play an important part in
the evolution of the universe.>
This is lucid and interesting to me. John, I can't figure out why, after
publicly announcing that you think I and half my state should be
guillotined because we don't want to turn our doctors into murderers of the
old and sick, you still try to help me out, which, in fact, you do. Why
are you helping me if you think my shoulders should be relieved of my head?
I am wedded to the cosmological constant because of my physical conception
of substance, of how gravity physically works, of the phenomenal continuum
between gravity and consciousness, only I am unsure if the "constant" is an
average constant, with local variability, or is an absolute constant. I
also may be confusing aspects of the cosmological constant with the
location and quantum effects of negative energy. I am, ahem, uncertain.
As an aside, since you're being helpful, I'll apologize for my reference to
"Kuhnian paradigms," I was just being irritating, rather out of character
for me. Thomas Kuhn was a no-good relativist, pah!
JC: <The question was not whether the Big Bang is true or not but weather
it's a scientific theory or not, you said it was not but the only reason
given is that you just don't like it. If you have other reasons I'd like to
hear them.>
Earlier, you wrote your idea of what constitutes a scientific theory: "Any
theory that makes predictions and can in principle be proven wrong is
Science." Now, I don't want to get into something I've exhaustively posted
on previously, but Popperian falsifiability is itself false, as I have
explained in detail. The truth about scientific theory is that it
logically *must* be equally falsifiable as verifiable, again as previously
posted. Verifiability comes when the words of scientific theory are
actualized in physical reality. This is why there is no boundary between
technology and science. Now, as to why the Big Bang is not science, it is
because physicists claim:
a) energy cannot be created from nothing and
b) energy was created from nothing.
This looks fishy to me. Perhaps I don't have the relativist's useful
emotional capacity for embracing contradiction.
JC: <A singularity is a point where an equation no longer works because
values become infinite. There is absolutely no doubt that our equations do
this at the center of a Black Hole, whether this fact has any physical
significance remains to be seen.>
It only remains to be seen after we've completely melted a black hole. In
the meantime, I will continue to view the postulation of singularities
physically existing inside black holes as kooky. First reality, then math,
not vice versa.
JC: <If you're not the greatest you're certainly the world's most certain
expert, and on every subject under the sun. Unfortunately absolute
certainty is a dime a dozen, being correct is not.>
This is a good example of the pot calling the kettle black. If your
fixation on information as an ontological primitive, your "everything is
digital" worldview, isn't as hardcore a certainty as any expression of
religious dogmatism I've seen, then I don't know what is. I'm certain of
that. I'm also certain that it's a delusional worldview that proceeds from
its metaphysical premises to the political consequences of guillotines
working overtime.
------------------------------------------------------------------------
Reilly Jones | Philosophy of Technology:
Reilly@compuserve.com | The rational, moral and political relations
| between 'How we create' and 'Why we create'
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