Ian White GM3SEK wrote:
Not everything about light (or EM waves) travels at the speed of light.

All EM waves (photons) travel at the speed of light.
Anything else would violate the principles of relativity.
Any detection of light results in the dissipation
(absorption) of the associated photons.

Standing waves are simply the RF equivalent of stationary optical
interference fringes.

That they appear to stand still is just an illusion.
Photons are continuously traveling at the speed of
light to get to your eyes where they are dissipated.
When you see an interference ring that appears to
stand still, you are actually receiving speed-of-
light photons into your eyes. (If the interference rings
were truly stationary, you wouldn't be able to see them.)

If the interference fringes are being absorbed, photons
are being dissipated. If the interference fringes are
being scattered, the photons are moving at the speed
of light. The photons either disappear or they travel
at the speed of light.

The photons in a transmission line cannot stand still.
Standing waves are caused by superposition and
interference between separate and distinct forward
and reflected energy waves. And the photons in the
standing wave are NOT standing still.

Consider two coherent nearly co-linear beams of light.
There are bright points of constructive interference
and dark points of destructive interference but the
interference has no effect on the two waves which
emerge from the superposition unaffected and continue
on their merry way. Those waves never slow down from
their speed-of-light velocity. The "stationary" bright
and dark points are an illusion.

At every point, photons are either being dissipated
or are traveling at the speed of light (including VF
of course). Nothing else is possible.
--
73, Cecil, http://www.qsl.net/w5dxp