rickman wrote:
On 10/9/2014 5:14 PM, Jerry Stuckle wrote:
On 10/9/2014 1:04 PM, rickman wrote:

The only mass a photon has is that which is equivalent to its energy, E
= mc^2.


I understand it has no rest math. But where does the mass come from?
There has to be mass to exert pressure. Does the mass just appear from
nowhere? I doubt it...

When a proton is accelerated and the mass quadruples, where does that
extra mass come from?

Photons are not accelerated; they either exist and are travelling at the
speed of light (in the medium) or they don't exist.

And before you ask, the speed change in the local frame due to a change
in medium is instantaneous, which would be impossible if they had rest
mass.


--
Jim Pennino