sci.physics.particle

On Mar 16, 2:04 pm, Tom Roberts wrote:
> BradGuth wrote:
> > On Mar 16, 9:14 am, Tom Roberts wrote:
> >> [about Shapiro time delay]
>
> > But photons clearly represent mass,
>
> One must be very careful when attempting to say something like this, and
> the photon itself clearly has zero mass -- that is part of the
> definition of "photon". I have no idea what you mean by "represent" here.

A zero mass photon dump truck might haul a wee bit of mass. Therefore
a given photon can represent mass, though however extremely wee it
might be.

BTW, of passing near the sun, what's the all inclusive (meaning full
electromagnetic spectrum) worth of photon population/cm3 ?

>
> > thus the solar atmosphere of
> > photons does offer mass for other passing photons to interact with.
>
> When we say "solar atmosphere" we don't mean photons at all. We mean the
> usual sort of things that make up an atmosphere: gases and particulates
> floating in the gases. The total mass of the solar atmosphere is utterly
> negligible compared to the mass of the sun (just as it is for earth).

Then perhaps you could trying thinking outside of that mainstream box.

>
> I mentioned the solar atmosphere because some people think the Shapiro
> time delay is due to it (such an atmosphere has an altitude-varying
> index of refraction, which _could_ behave like the Shapiro time delay).
> It's just that actual measurements of the solar atmosphere and its
> properties completely refute that claim.
>
> Tom Roberts

As long as your zero mass photon dump trucks are always empty little
buggers, you could be correct.
. - Brad Guth