[Physics] Gravitational Time Dilation and Gravitational Redshift - two separate things?

Thu Dec 6 16:17:39 CET 2018

Hi Ilja,  Excellent! I think we see it the same way. : )  Doug

On Thu, Dec 6, 2018 at 2:28 AM Ilja Schmelzer <ilja.schmelzer at gmail.com>
wrote:

> Again, my point to replace the wave with hand-waving was to make clear
> that the number of wave fronts received, if one looks at them in
> absolute background time, does not change.  What changes is the
> frequency, because it is measured with clocks, and clocks go slower,
> so that the same number of wave fronts during the same absolute time
> more means, in clock time, more wave fronts in one second, thus, a
> blue shift.
>
> And there is, nonetheless, also a relativistic mechanism for bending
> light.  First, because there is also a length contraction, but the
> main point is the change in the coordinate speed of light. That a
> change in the speed of light causes a bending can be easily seen in a
> prism.  And if one looks at GR through the Lorentz ether
> interpretation, it is clear that it is the coordinate speed which
> matters, and this coordinate speed changes.
>
> In fact, it is a simple rule:  Whenever it seems that SR/GR have
> something wrong, use the Lorentz ether interpretation to look at the
> problem.  In the Lorentz ether, the problem usually disappears.
>
> This is because the spacetime interpretation is in conflict with
> common sense intuitions, the Lorentz ether not. The equations are the
> same (see http://ilja-schmelzer.de/ether ) but all that is in conflict
> with common sense disappears.
>
> 2018-12-05 22:30 GMT+01:00, Doug Marett <dm88dm at gmail.com>:
> > Hi Ilja,
> >
> >     Yes, I agree with you that " the only change in the frequency is
> > because of the clocks (which have to be used to measure the frequency of
> > the hand-waving", but the red-shift of the light can't be "the same
> thing"
> > in my mind because, as you say, from the "point of view of the background
> > time coordinate, there is no change in frequency".
> > So if there is no change in frequency from the source to the receiver,
> > there is no relativistic mechanism by which the EM wave is made to bend,
> > since the bending is supposed to be caused by the progressive change in
> > frequency through the gradient. Quite literally, for EM waves approaching
> > the earth at an angle, the portion of the wavefront closer to the earth
> > must contract compared to the portions further away, eliciting a
> > progressive bend towards the surface, and Einstein attributes this to a
> > change in frequency of the wave acted upon by the grav. gradient, which
> is
> > something physical independent of the clocks. Einstein's idea also
> creates
> > another paradox, that a receiver on the surface will receive more
> > wave-fronts than are emitted by the transmitter at altitude - if this
> were
> > true we would have a free-energy generating device!
> >
> > I think the only way out of this is to argue that it is the change in the
> > speed of light with altitude and the associated change in wavelength that
> > causes light to bend in the gradient, and frequency remains preserved.
> > Einstein himself said in 1911 that this explanation was equivalent to his
> > own (except for the energy change). Then there is only the one frequency
> > effect due to the clocks and no problem with free energy. But then the
> > black hole theory has to be a fiction.
> >
> > Doug
> >
> >
> > On Wed, Dec 5, 2018 at 3:52 PM Ilja Schmelzer <ilja.schmelzer at gmail.com>
> > wrote:
> >
> >> No, the signal will be blue-shifted only once.
> >>
> >> This can be best seen if one replaces the wave by a hand-waving person
> >> and looks at the time when the light signal of "hand up" and "hand
> >> down" arrive.
> >>
> >> If we look at this in coordinates which are natural for a stable
> >> configuration, thus, a metric of the form g_mn (x^i) dx^m dx^n with
> >> the metric coefficients depending only on the spatial coordinates, and
> >> assume the handwaving guy as well as the observer at rest, the light
> >> rays for "hands up" and for "hands down" are the same trajectories,
> >> only with a shift in the time coordinate t.
> >>
> >> Thus, from point of view of the background time coordinate, there is
> >> no change in the frequency.  Thus, the only change in the frequency is
> >> because of the clocks (which have to be used to measure the frequency
> >> of the hand-waving).   So, they are the same thing.
> >>
> >> 2018-12-04 22:12 GMT+01:00, Doug Marett <dm88dm at gmail.com>:
> >> > Hi All,
> >> >
> >> >     This just came up in a question I had to my website - it has to do
> >> with
> >> > the Pound-Rebka experiment and whether gravitational time dilation of
> >> > clocks and gravitational redshift of EM are two different things or
> the
> >> > same thing. The problem is set out by L.B. Okun is plain language in
> an
> >> > article here: https://arxiv.org/pdf/hep-ph/0010256.pdf
> >> >    The essence of it is that if you take a clock and move it from the
> >> > ground to the top of a tower, the clock should speed up in it's rate
> at
> >> the
> >> > higher altitude. If you then send an EM signal from this clock back to
> >> the
> >> > ground, Einstein says that the EM should be blue-shifted. However,
> this
> >> > would mean that the signal sent to the ground has now been
> blue-shifted
> >> > TWICE, once due to the clock speeding up,  and once due to the fall of
> >> the
> >> > EM through the gravitational gradient.
> >> > However, the Pound-Rebka experiment finds that it is blue-shifted only
> >> > once. So which effect is redundant, gravitational time dilation of
> >> > clocks
> >> > or gravitational red-shift of light? They can't be the same thing,
> >> > since
> >> > the latter is an operation performed on the EM during transit, and is
> >> > supposed to make it bend. And the former is something which happens to
> >> > clocks independent of EM signals sent between them.
> >> > Interestingly, the experiment proposed by Okun to answer the question
> >> > was
> >> > performed in a slightly different form by Tom Van Baak as described
> >> > here:
> >> >
> >> > http://leapsecond.com/great2005/
> >> >
> >> > Another link that is useful is the paper here which examines the math
> >> used
> >> > in the Pound-Rebka experiment and finds it is full of errors!
> >> >
> >> > http://milesmathis.com/pound.html
> >> >
> >> > Just wondering if anyone else is aware of this apparent contradiction
> >> > in
> >> > the relativistic thinking : )
> >> >
> >> > Doug
> >> >
> >>
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> >>
> >
>
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