Massie wrote:
>
> George Murphy wrote:
> >
> > Adam Crowl wrote:
> > >
> > > Hi ASA
> > >
> > > Dick, I think you might've over-reacted. I don't think Jim's espousing
> > > Setterfield lunacy. Some research does indicate a higher velocity for c in
> > > the far, far past during the very hot and tiny phase of the Big Bang. By the
> > > time nucleii had formed it was down to its current value.
> >
> > What is this research? The claim is a bit puzzling since if relativity
> > is correct, c is simply a conversion factor between two units (km & sec) for measuring
> > intervals, so that having it change would be a little like the number of feet in a
> > mile changing.
> > (As I think I've noted before: Relativity does _not_ actually require
> > that light travel at speed c & if photons have a rest mass it won't. But that
> > wouldn't have any effect that I can think of in the early universe.)
> > Shalom,
> > George
> Since photons do not have a rest mass the ration of their mass at C and
> at zero is infinity. Bert M.
All we can say from observations is that from the absence of certain phenomena
at detectable levels (e.g., deviations from Coulomb's law, vacuum dispersion of light,
anomalous stresses in magnetized interstellar plasma) that the photon rest mass is
below a certain value, which at present is on the order of 10^-31 times the electron
mass. This means that on scales less than a few hundred light years and/or
corresponding time scales any effects of a putative photon rest mass are undetectable.
Shalom,
George
George L. Murphy
gmurphy@raex.com
http://web.raex.com/~gmurphy/
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