On Sep 17, 5:52*pm, Cecil Moore wrote:
wrote:
Are you proposing that a photon cannot travel slower than the speed of
light in a vacuum, or it cannot travel slower than the speed of light
in water or the speed of light through glass or air?

In any random medium, a photon cannot travel slower
than the speed of light through that medium. In
particular, photons associated with standing waves
do NOT stand still.
--
73, Cecil *http://www.w5dxp.com

What about Cerenkov radiation? In this case, beta particles with mass
travel faster than light in a water medium. So much for 'nothing can
travel faster than a photon'. It depends on the medium. If the medium
is a vacuum, then yes, nothing can travel faster than the speed of
light in that medium. Need to be careful. I have to Credit R. Clark
for pointinmg this out some time ago. See http://nuclear.mst.edu/research/reactor.html