On Tue, 16 Sep 2008 16:47:54 -0700 (PDT), Art Unwin
wrote:

On Sep 16, 4:32*pm, Cecil Moore wrote:
Photons have zero rest mass.
a photon at rest, how droll.
Cecil, this sounds like a regular poster David.Perhaps he is pulling
your leg with his nonsence

We know that we can accelerate an electron to 90% of the speed of
light - it happens every femtosecond in one of any 100 billion crt
displays still glowing in the world. Some of us know its mass at this
speed. A question for the Newtonian philosopherz:
"What is the mass of a photon traveling at 90% of the speed of
light?"

73's
Richard Clark, KB7QHC