"Abe" <dump@spamgourmet.com> wrote in message
news:MPG.1a8253cfb47c6c9298983e@news.cis.dfn.de...
> In article <lTWRb.6$AX.0@news-binary.blueyonder.co.uk>, jp006f9750
> @antispamblueyonder.co.uk says...
> >
> > "Lucas" <rufus729@msn.com> wrote in message
> > news:f8b57198.0401281305.3fca3e8c@posting.google.com...
> > >
> > > If a photon is massless, then why does it travel at different speeds
> > > through different media?
> >
> > That would be an interesting question without the preface "if a photon
> > is massless".
> > Photons ARE massless. Would you expect a radio broadcast to have mass?
> > Yet that too will vary its speed from medium to medium.
> > I don't know why the speed changes in a medium, and nor does anyone else
> > That leaves us with conjecture.
>
> I thought the particles of the medium absored, and then re-emitted, the
> photons, this interaction determining the "speed" of light through the
> medium?

I expect a dumb relativist gave you that wild idea.
They'll say anything to promote their religion, including downright lies.
Atoms can and do absorb light of particular wavelengths, just as radio
antennae do. Long waves (no longer popular) use enormous antennae, short
waves use shorter antennae, FM radio uses antennae that are 300,000,000
meters/sec divided by 100,000,000 Hz  = 3  divided by 2 for 1/2wavelength =
1.5 meters long, which is why you see these antennae on roof-tops tuned in
to 100MHz FM, Broadcast terrestrial TV uses even shorter wavelengths and
cell phones operating in the Gigahertz range have very short antennae. Cell
phones don't pick up long waves very well.
Atoms do not absorb and re-emit radio waves at all, and the CMBR does not
use any medium for its transmission.