From: Anton Sherwood (dasher@netcom.com)
Date: Tue Nov 04 1997 - 19:31:04 MST
: > >The velocity of light is (approximately) constant at 'c',
: John Clark wrote:
: > The speed of light in a vacuum is EXACTLY c for ANY observer.
Tony Hollick writes
: [1] A photon is absorbed and emitted by electrons as it passes
: through a glass block. The photon is decelerated, held, then
: re-emitted. Unless you believe that instantaneous transition from
: rest to 'c' is possible, the photon _must_ travel at intermediate
: velocities.
Absorbed and emitted, fine. Decelerated, baloney.
It's not the same photon!
: > >but only _relative to the emitting charge_.
:
: > Relative to anything.
:
: Obviously absurd. Relative to an adjacent photon in a coherent
: laser beam?
Meaningless, since to a photon there's no distance or passage of time.
: Or a parallel 'near-luminal' electron beam? C'mon...
Yes - ever bother to learn how to to add/subtract relativistic velocities?
Given two objects moving at velocities u,v (in the same direction),
each one sees the other moving at
|u-v| / (1-uv/cc);
if u=c, then the other object sees the photons moving at
(c-v) / (1-v/c) = c (c-v)/(c-v) = c.
The relative speed of two photons traveling together is
(c-c) / (1-cc/cc) = 0/0, undefined.
Read "Einstein for Beginners".
: > The index of refraction is a measure of how much a substance will slow down
: > light, water is pretty dense so light is only about 80% as fast as in a
: > vacuum for example.
:
: Notice the absurdity you're slipping into there. Water
: (ferinstance) is tiny molecules enormously widely spaced. The
: charges and neutrons are tiny particles enormously widely spaced.The
: space is a _perfect vacuum_ (except for the photons).
Wrong. The nuclei are vanishingly small, but the electron shells
take up most of the volume.
: > >This (along with photon-photon interaction -- see Jean-Paul Vigier
: > >et. al.) is the cause of the cosmic (Hubble) redshift, which is of
: > >course directly proportional to the distance stellar photons have to
: > >travel to get here.
:
: > And now you enter the Twilight Zone. All elements produce a unique set
: > of emission and absorption lines in their electromagnetic spectrum, a
: > redshift means that the information on the relative position of these
: > lines is preserved, they're just "shifted" to a longer wavelength. There
: > are only 2 things known to science that can produce a redshift:
: >
: > 1) The Doppler effect.
: >
: > 2) Gravity. (an effect discovered by Einstein by the way)
:
: Never seen a sunset? Filters? etc. etc. etc... >:-}
A filter is not a shift. The light of a sunset is not shifted to red
(as light from a receding star is): it's red because the blue is scattered
out of it (to make the day sky blue). What's left is the *same* red
that forms part of the white light of day.
By the way, if the speed of light depended on the emitting body,
interferometer telescopes would not work. They do.
[...]
: > and that car that runs on water.
:
: Here's a little quiz:
: ".2 MeV protons shot into lithium-7 atoms at room temperature and
: pressure produce a fusion reaction ( Li7 --> Be8 --> 2 alpha
: particles ) releasing 17 MeV of surplus -- fusion --energy."
: True or false? Wanna bet? >:-}
I should know better than to ask, but - the relevance of this is ... ?
: > Like all scientific theories General Relativity does not cover
: > everything, it says nothing about the strong or weak nuclear forces,
: > Einstein spent the last 20 years of his life trying to extend it into
: > those areas and he failed, but that certainly doesn't mean General
: > Relativity is wrong.
:
: <Sigh>. Read Pais...
:
: When Relational Mechanics is extendedf into the realm of the nucleus
: (as it will be), it will become the Third Revision, "Relational
: Dynamics." Quantum Chromodynamics is densely packed with
: absurdities. Busting up QCD will be great fun! >:-}
Absurd, or counter-intuitive? Is there any reason to expect
the nuclear world, of which we can have no direct experience,
to behave like the macro world which has shaped all our intuitions?
: > >An infinite Universe has nowhere to expand _into_. Right?
:
: > Wrong.
:
: Yeah? Infinity into infinity = zero.
Undefined, but zero is perhaps the least valid quotient. Try it:
1 * oo = oo
2 * oo = oo
oo * oo = oo
0 * oo = ?
Anton Sherwood *\\* +1 415 267 0685 *\\* DASher@netcom.com
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