On 17 May 2007 08:55:58 -0700, Pentcho Valev wrote:
On Nov, 8, 2003, Harry (Tom Roberts' student) wrote in
sci.physics.relativity:
Pound-Rebka (Snider). The higher clock measures frequency as less.
Its clockrate is greater by the same amount to reconcile this. Why
should light lose energy between FOR's. The same energy is accounted
for "fully" by the clockrates that measure it. The textbook statement
"AND light loses energy" is mixing FOR's.
I have read this before, in more detail by Ron Hatch, if I remember
well he concluded the same, as the GPS measurements obviously validate
the frequency effect, leaving zero for the energy loss effect; and
conservation of cycles also forbids the energy loss hypothesis.
Tom Roberts (the Albert Einstein of our generation) replied:
I don't know what you are asking (if anything). But the Pound & Rebka
and Pound & Snider experiments clearly show that the frequency of an
emitted light beam as measured by a receiver depends upon the
respective heights of emitter and receiver in the gravitational field
of the earth.
This can be interpreted in several different ways:
1. Light loses energy as it rises, and gains energy as it falls down;
because for light E=hf this affects its frequency.
This is in direct analogy with massive particles (in that they gain/
lose energy as they fall/rise), But from other experiments (e.g.
rotating moessbauser experiments) it is clear that this is not the
whole story.
2. Clocks tick slower when they are lower in a gravitational field
than when they are higher.
This is the typical elementary explanation. But from other experiments
it is clear that this is not the whole story.
3. Spacetime is curved in accordance with Einstein's field equation,
and light rays follow null geodesics.
This is the GR approach, and it also explains the other experiments.
In the non-quantum domain so far this seems to be the whole story.
While it is not clear to me what the above-quoted statements are tying
to say, it appears to me they are attempting to mix (1) and (2), and
as a result get confused. In (1) and (2) you have to choose whether
clocks are affected, or whether light is affected; assuming both just
leads to confusion (as above). But once you choose, it is then quite
easy to get confused when looking at other situations; (3) does not
have this drawback -- NEITHER light nor clocks are affected by
gravitation, but there is curvature that affects how different
measurements relate to each other.
GR (3) also has the virtue of being quantitative, general, and in
incredibly-accurate agreement with all reproducible experiments within
its domain of applicability.
Tom Roberts
___________________________________________
[End of Tom Roberts' explanation]
Let me call the attention to two important points:
A. In discussing (1), Tom Roberts obviously thinks of the formula
frequency = (speed of light)/(wavelength)
However Roberts does not mention "speed of light". Why?
B. Roberts is right about the incompatibility of (1) and (2). That is,
the measured frequency variation is due either to the variation of the
speed of light in a gravitational field (confirmed by Einstein and
many relativity hypnotists) or to gravitational time dilation, but by
no means to both. In other words, if the speed of light "varies with
position" in a gravitational field, there is no gravitational time
dilation.
Pentcho Valev
It's not enough, Tom, to say spacetime curvature causes the redshift.
It needs further explication, specifics, such as below. GR isn't all
that clear. (In MTW Gravitation they have the helpful hint "just the
redshift to be expected....bla bla bla ...falling Lorentz frames".
They try to invoke the equivalence principle applied to falling
masses; it is not only unconvincing, but there is a bit of duplicity).
Pound Rebka redshift can be analyzed very easily in Dual Space
theory. Take the case of 1% impact from the well.
DST says the clock radiator that goes down in the well will become
slow by 1%, and c is also reduced by 1%, so the native wavelength is
unaffected.
The clock naturally radiates at the lower frequency and on the way up
as c regains 1%, so also it stretches the wavelength 1%. The frequency
retains its lower value that was generated by a lower energy
environment.
In any preferred explanation it should be possible to assign 1%'s to
all of a table of F, WL, c,or time and then be able to prove that it
doesn't violate either double redshift or loss of energy through
fatigue and the like. DS case:
time freq WL c
UP 1 1 1 1
DN 1 .9 1 .9
UpOut 1 .9 1.1 1
The usual claim of loss of frequency gh/c^2 combined with a faster
test clock upstairs, gives double redshift.
You don't need time dilation. In DST the region of the gravitating
mass is weakened by removal of material from pairspace to create the
said mass, so the clock and c are both less springy.
My equation dc^2/2dt = MG/r^2 tells how c recovers it speed on the way
out, and when integrated delivers the proper expression for redshift,
c' being the lower value of c:
Dc^2 = 2MG/r (int from R to oo)
c'/c = sqrt(1-2MG/r^2c)
Thus the redshift comes about as I explained above with this equation
to verify that
John Polasek