🚀 go-pugleaf

On Dec 30 2007, 8:06 am, Pentcho Valev <pva...@yahoo.com> wrote:
> On Dec 29, 10:39 am, Pentcho Valev <pva...@yahoo.com> wrote:
>
>
>
>
>
> > On Dec 29, 3:01 am, BURT <macromi...@yahoo.com> wrote in sci.physics:
>
> > > Light is blueshifted on its way into gravity.
> > > Light is redshifted on its way out.
>
> > Sometimes even Einsteinians explain this correctly:
>
> >http://www.blazelabs.com/f-g-gcont.asp"The first confirmation of a
> > long range variation in the speed of light travelling in space came in
> > 1964. Irwin Shapiro, it seems, was the first to make use of a
> > previously forgotten facet of general relativity theory -- that the
> > speed of light is reduced when it passes through a gravitational
> > field....Faced with this evidence, Einstein stated:"In the second
> > place our result shows that, according to the general theory of
> > relativity, the law of the constancy of the velocity of light in
> > vacuo, which constitutes one of the two fundamental assumptions in the
> > special theory of relativity and to which we have already frequently
> > referred, cannot claim any unlimited validity. A curvature of rays of
> > light can only take place when the velocity of propagation of light
> > varies with position."......Today we find that since the Special
> > Theory of Relativity unfortunately became part of the so called
> > mainstream science, it is considered a sacrilege to even suggest that
> > the speed of light be anything other than a constant. This is somewhat
> > surprising since even Einstein himself suggested in a paper "On the
> > Influence of Gravitation on the Propagation of Light," Annalen der
> > Physik, 35, 1911, that the speed of light might vary with the
> > gravitational potential. Indeed, the variation of the speed of light
> > in a vacuum or space is explicitly shown in Einstein's calculation for
> > the angle at which light should bend upon the influence of gravity.
> > One can find his calculation in his paper. The result is c'=c(1+V/c^2)
> > where V is the gravitational potential relative to the point where the
> > measurement is taken. 1+V/c^2 is also known as the GRAVITATIONAL
> > REDSHIFT FACTOR."
>
> Pound and Rebka found experimentally that the GRAVITATIONAL REDSHIFT
> obeys the equation f'=f(1+V/c^2), which is consistent with Einstein's
> 1911 equation c'=c(1+V/c^2) and the textbook formula
>
> frequency = (speed of light)/(wavelength)
>
> In fact, it is this textbook formula that made the creation of
> Einstein zombie world absolutely necessary - in any other world the
> transition from this formula to the conclusion that the speed of light
> is variable and obeys the equivalent equations c'=c(1+V/c^2) and c'=c
> +v would be obvious. In Einstein zombie world half of the Einsteinians
> fiercely teach that, in a gravitational
> field, the speed of light is CONSTANT:
>
> http://www.astronomynotes.com/relativity/s4.htm
> "Prediction: light escaping from a large mass should lose energy---the
> wavelength must increase since the speed of light is constant.
> Stronger surface gravity produces a greater increase in the
> wavelength. This is a consequence of time dilation. Suppose person A
> on the massive object decides to send light of a specific frequency f
> to person B all of the time. So every second, f wave crests leave
> person A. The same wave crests are received by person B in an interval
> of time interval of (1+z) seconds. He receives the waves at a
> frequency of f/(1+z). Remember that the speed of light c = (the
> frequency f) (the wavelength L). If the frequency is reduced by (1+z)
> times, the wavelength must INcrease by (1+z) times: L_atB = (1+z)
> L_atA. In the doppler effect, this lengthening of the wavelength is
> called a redshift. For gravity, the effect is called a GRAVITATIONAL
> REDSHIFT."
>
> http://helios.gsfc.nasa.gov/qa_sp_gr.html
> "Is light affected by gravity? If so, how can the speed of light be
> constant? Wouldn't the light coming off of the Sun be slower than the
> light we make here? If not, why doesn't light escape a black hole?
> Yes, light is affected by gravity, but not in its speed. General
> Relativity (our best guess as to how the Universe works) gives two
> effects of gravity on light. It can bend light (which includes effects
> such as gravitational lensing), and it can change the energy of light.
> But it changes the energy by shifting the frequency of the light
> (gravitational redshift) not by changing light speed. Gravity bends
> light by warping space so that what the light beam sees as "straight"
> is not straight to an outside observer. The speed of light is still
> constant." Dr. Eric Christian
>
> When Einstein zombies have already learned by rote that the speed of
> light is always CONSTANT, teaching that it is VARIABLE, that is
> teaching the truth, can only increase the confusion:
>
> http://www.math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/spe...
> "Einstein went on to discover a more general theory of relativity
> which explained gravity in terms of curved spacetime, and he talked
> about the speed of light changing in this new theory. In the 1920 book
> "Relativity: the special and general theory" he wrote: ". . .according
> to the general theory of relativity, the law of the constancy of the
> velocity of light in vacuo, which constitutes one of the two
> fundamental assumptions in the special theory of relativity [. . .]
> cannot claim any unlimited validity. A curvature of rays of light can
> only take place when the velocity of propagation of light varies with
> position." Since Einstein talks of velocity (a vector quantity: speed
> with direction) rather than speed alone, it is not clear that he meant
> the speed will change, but the reference to special relativity
> suggests that he did mean so."
>
> http://www.physlink.com/Education/AskExperts/ae13.cfm
> "So, it is absolutely true that the speed of light is _not_ constant
> in a gravitational field [which, by the equivalence principle, applies
> as well to accelerating (non-inertial) frames of reference]. If this
> were not so, there would be no bending of light by the gravitational
> field of stars....Indeed, this is exactly how Einstein did the
> calculation in: 'On the Influence of Gravitation on the Propagation of
> Light,' Annalen der Physik, 35, 1911. which predated the full formal
> development of general relativity by about four years. This paper is
> widely available in English. You can find a copy beginning on page 99
> of the Dover book 'The Principle of Relativity.' You will find in
> section 3 of that paper, Einstein's derivation of the (variable) speed
> of light in a gravitational potential, eqn (3). The result is,
> c' = c0 ( 1 + V / c^2 )
> where V is the gravitational potential relative to the point where the
> speed of light c0 is measured."
>
> Pentcho Valev

From http://en.wikipedia.org/wiki/Pound-Rebka_experiment :

"The Pound-Rebka experiment is a well known experiment
to test Albert Einstein's theory of general relativity.
It was proposed by R. V. Pound and G. A. Rebka Jr.
in 1959,[1] and was the last of the classical tests of
general relativity to be verified (in the same year).
It is a gravitational redshift experiment, which measures
the redshift of light moving in a gravitational field,
or, equivalently, a test of the general relativity prediction
that clocks should run at different rates at different places
in a gravitational field. It is considered to be the
experiment that ushered in an era of precision tests
of general relativity.

The energy associated with gravitational redshift over
a distance of 22.5 meters is very small. The fractional
change in energy is given by δE/E, is equal to
gh/c2=2.5x10-15."

In fact, the result of the Pound-Rebka experiment
(a  fractional change in frequency of 2.5x10-15)
doesn't need general relativity to be explained:

Let Nu the emitted frequency at the top of the
tower of height d = 22.5 m. The corresponding
energy of the photon is E = hNu, where h is
the Plank constant.
Let Nu0 the observed frequency at the bottom.
Assuming that m = hNu / c^2 represents the
photon's mass corresponding to the frequency Nu,
and mgd its potential energy at the top, where
g = 9.81 m/s^2 is the Earth's gravitational
potential (assumed to be constant), the observed
energy E0 of the photon is given by

E0 = E + mgd
     = hNu +  (hNu / c^2) * gd
     = hNu (1 + gd/c^2)
     = E (1 + gd/c^2) , or
Nu0 = Nu (1 + gd/c^2)

Note that
gd/c^2 = 9.81 * 22.5 / 9E16
           =~ 2.5E-15

Marcel Luttgens