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From: kovner%regina.DEC@decwrl.ARPA
Newsgroups: net.sf-lovers
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Message-ID: <1137@sri-arpa.UUCP>
Date: Wed, 23-May-84 17:23:43 EDT
Article-I.D.: sri-arpa.1137
Posted: Wed May 23 17:23:43 1984
Date-Received: Fri, 1-Jun-84 03:44:19 EDT
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To add more to the debate on FTL: (My qualifications: I have an ScM in
physics, with work in relativity and high-energy physics, although I
work as a software engineer, as I enjoy it more.)

>  (paraphrased) FTL ... would be the same as going backwards in time.

Time travel (without accelerating beyond the speed of light) is not (to my
knowledge) expressly forbidden in relativity, but it has its own set of
problems. (Physicists, and the rest of us, would have to give up
causality, but this is known, see the debate on getting rich thru time
travel.) In fact, in some ways, antiparticles may be regarded as plain 
particles travelling backwards in time, and are drawn this way in Feynman
diagrams.

(Time reversal has other problems in particle physics; it is
known that the decay of the neutral k-meson violates time reversal
symmetry, because it violates parity (handedness) and charge conjugation
at the same time, and the product of these must be conserved (Why? I don't
know; I can't understand the proof.))

Since physicists have been looking for tachyons (particles created at
greater than the speed of light, so they can't slow down to C), at least
some physicists believe that things may go back in time. It looks like
tachyons either do not exist, or that they do not interact with normal
matter, as none have been found in at least 10 years of looking, but...

Another point about time reversal and relativity; this one my own theory.
Background: I was able to show the existence of black holes using only
special relativity and Newtonian gravity. (My calculation of the
Schwartzchild radius is off by a factor of 2; I think this is due to
errors in by calculation of the gravitational potential energy.) This was
done by assuming that time dilation is related to the total energy of a
particle. The special relativity equations give, for a particle with mass
and kinetic energy only, that the t/t'=E/M; where t/t' is the ratio of
time in the 'lab' to time measured by the moving object, and E is its
total energy (including mass) and M is its rest energy (MC**2). If one
takes a particle in a gravitational field, the result shows that the ratio
can become NEGATIVE (inside a black hole). (Does this mean time travel is
possible? Maybe, but the hard part is then stopping! )

Finally, general relativity (of which I understand little) does allow
(maybe) 'wormholes' -- connections between points in space which are
otherwise far apart. The only problem with using such things is that they
are found in rotating charged black holes.

This leaves plenty to think about, but I'll add one personal opinion: the
singularities of general relativity will somehow be eliminated. After all,
in quantum electrodynamics, the electron has infinite charge and mass ( or
is it zero mass?) if it could be removed from interactions with everything
else. Those interactions are also infinite, and so cancel. (this can be
proven mathematically, but again, I don't understand the proof.) The
result is the measured charge and mass. I do not know the result of
renormalizing a black hole, and I don't think anybody else does, either,
as gravity has not been quantized.

To end all this raving: The truth is stranger than fiction, even science
fiction.

Steve Kovner DEC Parker St. facility.
(DEC Engineering net:  REGINA::KOVNER )