From: "JACK L. URETSKY (C) 1996; HEP DIV., ARGONNE NATIONAL LAB, ARGONNE, IL 60439" <JLU@hep.anl.gov>
Date: Sun, 30 Jun 1996 22:39:51 -0500 (CDT)
Hi all and David Bowman-
Hmmm, I dunno, David. Suppose that the photon did have a small
mass while still being the lightest particle in nature. What would special
relativity look like then? What kind of argument would lead us to the
Lorentz transformation? We would, of course, discover the constant "c"
by balancing energy-momentum and mass differences for unstable nuclei.
Also, the consequences for cosmology, with all of that mass hanging around,
would be profound. But your insistence on a particular postulate as
"fundamental" intrigues me. So let's change one of the facts and see
what happens.
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Some other errors and/or misconceptions propagated by textbooks that irritate
me are the usual explanations of rainbow formation and the use of the
constancy of the speed of *light* as the 2nd postulate of special relativity,
rather than the requirement of no instantaneous-action-at-a-distance (with the
corollary that there must be a speed limit of causation whose value we
conveniently label as c). The constancy of this speed limit c is itself a
theorem of the first two postulates. The reason that light happens to travel
at this speed limit is that the photon happens to be massless. If photons
happened to have a nonzero mass then the group velocity of light would be less
than c, but this would have no effect on the validity of special relativity
itself.
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Regards,
Jack
"These several facts prove nothing, for one cannot deduce a principle from so
few examples, but they do at least indicate that the ability to learn to spell
correctly is a gift; that it is born in a person, and that it is a sign of
intellectual inferiority. By parity of reasoning, its absence is a sign of
great mental power."
Mark Twain, "Extract from Eve's Diary'.