K7ITM wrote:

"Let's see... e=m*c^2. Now what c is that?

I think I know which one, and as far as I know there hasn't been a
dispute about that on RRAA. The question posed on the newsgroup, and
the one which still seems to be a point of contention is which one
should go in *this* equation:

f = c / w

I maintain the answer is still - it depends on the medium.

I am sorry to have gotten so many pairs of panties wadded up about
this. Seemed a noncontroversial notion to me at the time.

73, Jim AC6XG

Jim Kelley wrote in news:eve92l$mip$1
@news.service.uci.edu:



K7ITM wrote:

"Let's see... e=m*c^2. Now what c is that?

I think I know which one, and as far as I know there hasn't been a
dispute about that on RRAA. The question posed on the newsgroup, and
the one which still seems to be a point of contention is which one
should go in *this* equation:

f = c / w

I maintain the answer is still - it depends on the medium.

Jim, I am not a physicist... but I recall when introduced to e=m*c^2 at
high school, that "c" was defined as "the velocity of light in a vacuum".

If the "in a vacuum" qualification was unnecessary, if wasn't relevant, I
wonder why they complicated and restricted the definition?

I am with you (until someone presents a convincing argument otherwise).

This leaves all those books, software etc giving a value for "c" as not
necessarily in need of revision.

Owen

john Wiener wrote:
c/c' = n, index of refraction for the c' medium, (c always used as the
constant in a vacuum).

That's the convention we used at Texas A&M
50 years ago.
--
73, Cecil http://www.w5dxp.com

Being that I have zero qualifications as an expert on C I will tell
you how I see it.. pun intended

First, C is specified as the speed of photon travel in a vacuum, per
definition... Or as our attorney brethern say it, Per Se...

Second, C' is the measured speed of the propagation of the wave front
we call light through an atomic medium, air, water, glass, diamond,
etc....

The thing to keep in mind is that the two, C and C', are not identical
physical entities...
C is the unimpeded propagation of a photon - i.e. a single entity -
through a non atomic medium we call a vacuum - 'aether' if you will...
The photon that left Proxima Centauri ~4 years ago is the same photon
that slams into the front lens of the Hubble telescope (according to
that photon's wrist watch that ~4 years happened instantaneously, but
that's another rant)...
Now if you were in orbit at the eyepiece of the Hubble the photon that
enters your retina is not the same Proxima Centauri photon that
slammed into the Hubble's mirror... And that makes all the
difference...

C' happens when the photon smashes into the Hubble's glass and is
caught up in the electrical fields sorrounding the atoms making up the
glass, primarily the electrical field of the outer (valence) electrons
of the Protons... Like a house fly at full speed hitting a spiders web
the photon begins to tumble and veer sideways and rapidly decellerate
causing it to dump it's energy, i.e. radiate an electromagnetic field
of it's own... The electron's field absorbs the energy radiated off
the photon, causing in increase in the electrons energy level, usually
forcing it to jump to a higher 'orbit'...

Now at this instant the photon has disappeared (eaten by the spider)
and the electron has been pumped up (like Hulk Hogan)... After a short
interval the electron drops back to a lower energy level emitting a
new photon... This photon takes off like a scalded rabbit at C (or
very near C) but doesn't get far before another electron field sucks
it up again... And so it goes for the passage of the photon (actually
information) through the atomic structure of the transparent
material... The photon that pops out of the eyepiece and slams into
your retina is the lebenty sebenth generation descendent of the
original photon that hit your scope... The process of repeated
absorption and emission of a photon by multiple electrons is what
slows the light (wave front) when it travels through transparent
material... (and also what creates refraction, circles of confusion,
and a bunch of other phenomena)

Clear as mud, eh wot...

denny / k8do

On Apr 5, 11:00 am, Richard Clark wrote:
On 5 Apr 2007 07:36:49 -0700, "MRW" wrote:

c = f*w (c = m/s, f = frequency, w = wavelength)

This frequency is relevant ONLY for vacuum (or with a very, very
slight alteration) air.

Now, it may seem that all air is air, but no. There are slight
variations here too that on the global scale small shifts make large
changes. Those small shifts are accounted for by pressure, water
content (vapor), and temperature.

73's
Richard Clark, KB7QHC

Same thing happens with light through water, the light slows down but
doesnt change in color(frequency).

Jimmie