From: Robert J. Bradbury (bradbury@www.aeiveos.com)
Date: Sun Aug 22 1999 - 07:33:48 MDT
On Sun, 22 Aug 1999, John Clark wrote:
>
> Tipler found a solution in General Relativity that shows that an
> infinitely long, extremely dense cylinder made of Neutronium (the stuff of
> Neutron Stars)
Aha, I'll invoke the "Use of Magic Physics" warning when people use
terms like "infinitely long", "infinitely dense", "negative mass",
etc.!!! Only half :-).
> 2) The very rapid rotation would cause the cylinder to fly apart. This is
> much more than just an Engineering difficulty, no known force in Physics
> would be strong enough to hold the cylinder together, not even the strong
> nuclear force.
John, interestingly enough there is a concept called "momentum transfer"
that has shown up in some astroengineering articles I've reviewed for
the Dyson shell work. It is used in the recently mentioned "The Saga
of the Cuckoo" as well. If your Neutronium "cylinder" were surrounded
by a large number of particle accelerators whose beam emissions were
perpendicular to the axis of rotation, and the force of the beams
striking the outside wall of the cylinder were high enough, it would
be impossible for the cylinder to "fly apart". I suppose if you
angled the beams slightly, they could impart some of the force
required to rotate the cylinder at high velocity.
Now, the thought question for you (since you know more physics than I),
is what happens when a beam of protons (or I suppose neutrons if you
want really high density beams) hits a neutronium cylinder?
Can neutrons interact in any way so as to produce photons?
[It seems kind of strange since there are no electrons involved.]
Do some strange interactions occur so that neutrinos/antineutrinos
get produced? [Since presumably those are the only things that
can radiate "out" through the incoming mass streams.]
This is related to a question I've wondered about the maximum density
of light. Say I have a number of really large lasers (powered by
stars) arranged in a large sphere, perhaps like a globular cluster.
Say I beam all of those lasers at a single point in space. What
happens? Do I generate matter? Do the beams simply pass through
each other?
A related question would appear to be -- since a mass density
above a certain level will generate a black hole, will an
energy density equivalent to that mass density (by e=mc^2)
do the same thing?
If so, wouldn't this be a way of generating small black holes
that science fiction writers and some physicists use for
various purposes?
And finally, if laser light to black hole conversion is feasible,
does anyone have any idea how much we would have to juice the
laser at Lawrence Livermore to create black holes (of say
neutron mass or larger).
Thought questions for the day...
Robert
And as an interesting postscript...
One by one the stars blinked and went out as the SIs
hurled black holes across the voids of space seeking to
destroy each others fuel sources. The fuel that powered
the future modelling computers was essential for the
prediction of paths that would avoid the ever increasing
density of black holes that slowly drained the intelligence
from the the universe. Far far away, in a quiet corner,
the Anders SI and the Robert SI were watching...,
waiting..., knowing that one day those black holes
would have to evaporate, providing enough energy to
live again. They slept while the universe fell slowly
into darkness.
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