SR time dilation on remote objects ?

Marcel Luttgens wrote:
Bjoern Feuerbacher wrote in message ...

Marcel Luttgens wrote:

Bjoern Feuerbacher wrote in message ...


Marcel Luttgens wrote:


Bjoern Feuerbacher wrote in message ...


[snip]



Hint: LET and SR give the same results. And that result is *not* the
one *you* obtain.



I presume that *your* formula is Nu(o) = Nu sqrt((1-v/c)/(1+v/c)),

Yes. Nice that you finally got this.

Hint: that formula has been *tested*. See e.g. he
http://www.mathpages.com/rr/s2-04/2-04.htm
For a more detailed description of that experiment, see he
http://spiff.rit.edu/classes/phys314/lectures/doppler/doppler.html

Care to compare the predictions of your formula to the results
obtained there?

See also section IV of this article:
http://arxiv.org/pdf/physics/0408047


Oh, and while you are at it, you could also explain the transverse
Doppler effect, which also was tested experimentally, and where also
agreement with the predictions of SR was found.



I don't deny that such formula makes sense, I simply claim that
it cannot be applied to light emitters/receivers subject to
"space" expansion, because such expansion is symmetrical.

And that claim by you makes no sense at all.

What do you mean, exactly, by saying that the expansion is "symmetrical"?


[snip]


But you should realize that light is not sound, because
of the speed limit c.

*sigh* Obviously. That's why one uses Nu(o) = Nu sqrt((1-v/c)/(1+v/c)),
not Nu(o) = Nu / (1+v/c), if you didn't notice.



No, those who use Nu(o) = Nu sqrt((1-v/c)/(1+v/c)) because of time dilation,
forget that in an expanding universe,

*sigh* For the 100th time: The Doppler shift formula of SR and LET,
Nu(o) = Nu sqrt((1-v/c)/(1+v/c), is *not* used in cosmology.


the identical time dilations
on the emitter and the receiver cancel each other.

Why should the time dilations be identical?


And, again for the 100th time: the time dilation seen in cosmology
has *nothing* to do with the time dilation of SR or LET.


[snip]


No time dilation factor
is needed in an expanding universe, because the light source and the
observer are simultaneously receding wrt each other.

Irrespective of a time dilation factor is needed or not, your
formula above is simply wrong. If you think otherwise, present
a derivation which is *not* based on "the distance changes, but let's
consider that it it constant anyway".



IOW, you are saying that Nu(o) = Nu / (1+v/c) sould be used when
the light source is receding from the observer.

NO.

I say that for real movements, one should use Nu(o) = Nu
sqrt((1-v/c)/(1+v/c)) (regardless if the source or the observer is
moving, since motion is relative!), and in cosmology, one should use
1+z = R(t0)/R(t) for the red shift (reminder: R is the curvature
radius of the universe).


Nu(o) = Nu * (1-v/c) should also be used when the source is receding
from the observer, because light can be considered as a train of photons
of wavelength lambda emitted at c by the source. But as the source
is moving away at v, the frequency Nu(o) at which the photons are
emitted becomes Nu * (c-v)/c for the observer.

That claim is still utter nonsense.



Realize that, for the observer, the photons are not emitted at c,
but at c-v, by the atoms of the source.

No, that is utter nonsense. For the observer, the photons are emitted
at c, not at c-v. Both in SR and in LET.


Hence their frequency is lessened by a factor (c-v)/c.

False premise.


[snip]



The page is interesting. It helps to show that the time dilation
effects on the source and the emitter cancel each other:

Only if you look at the situation where light is *reflected*!
I.e. the emitter and the source are the *same* then!


1) Absence of time dilation.

The radar emits at a frequency Nu, the car is moving away at v
from the radar.
The frequency Nu1 received by the car is Nu * (c-v)/c.
The moving car is now the source and emits at Nu1.
The frequency Nu(o) received by the radar is, according to
the *sound formula*, Nu1 * c/(c+v), hence
Nu(o) = Nu * (c-v)/c * c/(c+v)
= Nu (c-v)/(c+v)
Thus, 1+z = lambda(o)/lambda = (c+v)/(c-v), and
z = 2v/(c-v) = 2 v/c / (1-v/c)

2) There is time dilation on both objects.

Notice that, unlike the Doppler shift for sound, it does not matter
whether the source or the observer is the one in motion.
Only their relative velocity is needed when using the LET formula
Nu(o) = Nu sqrt(1-v^2/c^2)/(1+v/c).

Nice that we agree at least on that.


The radar emits at a frequency Nu, the car is moving away at v
from the radar.
The frequency Nu1 received by the car is Nu sqrt(1-v^2/c^2)/(1+v/c).
The moving car is now the source and emits at Nu1.
The frequency Nu(o) received by the radar is
Nu1 sqrt(1-v^2/c^2)/(1+v/c), hence
Nu(o) = Nu sqrt(1-v^2/c^2)/(1+v/c) * sqrt(1-v^2/c^2)/(1+v/c)
= Nu (1-v^2/c^2)/(1+v/c)^2
= Nu (1-v/c)(1+v/c)/((1+v/c)(1+v/c))
= Nu (1-v/c)/(1+v/c)
= Nu (c-v)/(c+v)
Thus, 1+z = = lambda(o)/lambda = (c+v)/(c-v), and
z = 2v/(c-v) = 2 v/c / (1-v/c),

which is the same formula as the one obtained with no time dilation!

Nice for you.

And now explain how this situation, where light is *reflected*, is
relevant for cosmology.


Bye,
Bjoern

On Wed, 22 Sep 2004 11:14:02 +0200, Bjoern Feuerbacher
wrote:

Well, apparently in his universe, the matter is not accelerated, but
the photons are.

Who cares about consistency...



Bye,
Bjoern
"A foolish consistency is the hobgoblin of little minds, adored by
little statesmen and philosophers and divines. Speak what you think
today in hard words and tomorrow speak what tomorrow thinks in hard
words again, though it contradicts everything you said today." ..Ralph
Waldo Emerson in Self Reliance.

Matter and photons may both be transitory in the current universe.

On Wed, 22 Sep 2004 14:42:35 +0200, Bjoern Feuerbacher
wrote:

Notice that this is a totally unsupported assertion, and that you
still keep ignoring 99% of the evidence which shows that the
universe *is* expanding.

The 5% that we can see and measure appears to be.

On Wed, 22 Sep 2004 14:43:41 +0200, Bjoern Feuerbacher
wrote:

And you don't think that the words "static" and "acceleration" are
contradictory?

Bye,
Bjoern

That certainly appears to be so. In fact , does anything in the
universe show much tendency to `stasis'?

vonroach wrote in message . ..
On Wed, 22 Sep 2004 14:43:41 +0200, Bjoern Feuerbacher
wrote:

And you don't think that the words "static" and "acceleration" are
contradictory?

Bye,
Bjoern

That certainly appears to be so. In fact , does anything in the
universe show much tendency to `stasis'?

Bjoern is playing with words. A stable (or static, in any case, not
expanding) universe doesn't exclude a negative acceleration cH redshifting
light.

Marcel Luttgens

Bjoern Feuerbacher wrote in message ...
Jonathan Silverlight wrote:
In message , Marcel
Luttgens writes


In my model, everything is *very* close to the center of the (stable)
universe,
which is so big that a distance c/H is so much smaller than the universe
radius, that the universe could as well be considered as infinite.
If it were mathematically infinite, the Earth, and all of its points,
would of course coincide with its center. In particular, all points
of the trajectory of a light signal (emitted for instance by a galaxy)
would be at the center of a sphere of radius c/H centered on the
universe's
center, and thus subject to an acceleration cH explaining its redshift.


What acceleration? I thought your universe was static.

Well, apparently in his universe, the matter is not accelerated, but
the photons are.

Who cares about consistency...

Like photons, material objects should also be subjected to such
*negative* acceleration, but this would be difficult to observe,
since all objects are gravitationally linked (for instance, a satellite
orbiting a planet), and the "deceleration" effect would be masked by
the gravitational effects.




Bye,
Bjoern

Marcel Luttgens

Marcel Luttgens wrote:
vonroach wrote in message . ..

On Wed, 22 Sep 2004 14:43:41 +0200, Bjoern Feuerbacher
wrote:


And you don't think that the words "static" and "acceleration" are
contradictory?

Bye,
Bjoern

That certainly appears to be so. In fact , does anything in the
universe show much tendency to `stasis'?


Bjoern is playing with words.

No, not at all. I'm merely using the standard definitions of the
words in physics.


A stable (or static, in any case, not
expanding) universe doesn't exclude a negative acceleration cH redshifting
light.

Why should the negative acceleration work only on the photons, but not
on the matter?


Bye,
Bjoern

Marcel Luttgens wrote:
Bjoern Feuerbacher wrote in message ...

Jonathan Silverlight wrote:

In message , Marcel
Luttgens writes


In my model, everything is *very* close to the center of the (stable)
universe,
which is so big that a distance c/H is so much smaller than the universe
radius, that the universe could as well be considered as infinite.
If it were mathematically infinite, the Earth, and all of its points,
would of course coincide with its center. In particular, all points
of the trajectory of a light signal (emitted for instance by a galaxy)
would be at the center of a sphere of radius c/H centered on the
universe's
center, and thus subject to an acceleration cH explaining its redshift.


What acceleration? I thought your universe was static.

Well, apparently in his universe, the matter is not accelerated, but
the photons are.

Who cares about consistency...


Like photons, material objects should also be subjected to such
*negative* acceleration, but this would be difficult to observe,
since all objects are gravitationally linked (for instance, a satellite
orbiting a planet),

Wrong. Not all objects are gravitanionally linked. E.g. galaxies
which are distant from each other are not linked at all.


and the "deceleration" effect would be masked by
the gravitational effects.

Well, didn't you say that the deceleration of the photons *is* due
to gravitation?


Bye,
Bjoern

Bjoern Feuerbacher wrote in message ...
Marcel Luttgens wrote:
Bjoern Feuerbacher wrote in message ...


snip, because those points have already been discussed


But you should realize that light is not sound, because
of the speed limit c.

*sigh* Obviously. That's why one uses Nu(o) = Nu sqrt((1-v/c)/(1+v/c)),
not Nu(o) = Nu / (1+v/c), if you didn't notice.



No, those who use Nu(o) = Nu sqrt((1-v/c)/(1+v/c)) because of time dilation,
forget that in an expanding universe,

*sigh* For the 100th time: The Doppler shift formula of SR and LET,
Nu(o) = Nu sqrt((1-v/c)/(1+v/c), is *not* used in cosmology.


GR is used, but is GR right?

[snip]


No time dilation factor
is needed in an expanding universe, because the light source and the
observer are simultaneously receding wrt each other.

Irrespective of a time dilation factor is needed or not, your
formula above is simply wrong. If you think otherwise, present
a derivation which is *not* based on "the distance changes, but let's
consider that it it constant anyway".



IOW, you are saying that Nu(o) = Nu / (1+v/c) sould be used when
the light source is receding from the observer.

NO.

I say that for real movements, one should use Nu(o) = Nu
sqrt((1-v/c)/(1+v/c)) (regardless if the source or the observer is
moving, since motion is relative!), and in cosmology, one should use
1+z = R(t0)/R(t) for the red shift (reminder: R is the curvature
radius of the universe).


Yes, with many assumptions, like Omega M, flat universe, etc...
With some of those *needed* (should I say ad hoc?) assumptions,
GR gets about the same results as those obtained with a stable
universe and a "deceleration" cH. Use Ted Wright's calculator
if you are not yet convinced.

But I don't understand what you mean by "real" movements. Are
movements in cosmology not "real"?


Nu(o) = Nu * (1-v/c) should also be used when the source is receding
from the observer, because light can be considered as a train of photons
of wavelength lambda emitted at c by the source. But as the source
is moving away at v, the frequency Nu(o) at which the photons are
emitted becomes Nu * (c-v)/c for the observer.

That claim is still utter nonsense.



Realize that, for the observer, the photons are not emitted at c,
but at c-v, by the atoms of the source.

No, that is utter nonsense. For the observer, the photons are emitted
at c, not at c-v. Both in SR and in LET.

I show hereafter that the SR formula Nu(o) = Nu sqrt((1-v/c)/(1+v/c))
cannot be right. As SR is a subset of GR, how could GR be right?



Hence their frequency is lessened by a factor (c-v)/c.

False premise.


[snip]

Thus, 1+z = = lambda(o)/lambda = (c+v)/(c-v), and
z = 2v/(c-v) = 2 v/c / (1-v/c),

which is the same formula as the one obtained with no time dilation!

Nice for you.

And now explain how this situation, where light is *reflected*, is
relevant for cosmology.

Because those two identical results show that something must
be wrong in the derivation of the SR formula
Nu(o) = Nu sqrt((1-v/c)/(1+v/c))

Let's apply the sound Doppler to light:

1) The light source is receding at v from light the receiver

Then Nu(o)/Nu = c/(c+v), which leads to z = v/c.

Such formula is nonsensical for light, because with it, z can never be
greater than 1. Or galactic light can have much bigger redshifts
than 1.

Let fS = c/(c+v)

2) The receiver is receding at v from the emitter

Then Nu(o)/Nu = (c-v)/c, which leads to z = (v/c)/(1-v/c)

This formula gives sensible results.

The same formula can be obtained when the source is moving
by hypothetising a stable universe where light is subject at
every point of its trajectory to a negative acceleration cH.
Notice that the reddening is then absolute, in the sense that
it is independent from observers.

Let fR = (c-v)/c

Now, the SR formula Nu(o) = Nu sqrt((1-v/c)/(1+v/c)), can be written

Nu(o) = Nu sqrt((c-v)/c) * c/(c+v)), or
Nu(o)/Nu = sqrt(fR * fS)

The SR frequency ratio is simply the geometric mean of the frequency
ratio fR obtained when the receiver is receding and the frequency ratio
fS corresponding to the receding source!

Since fS is wrong for light, the SR formula must be wrong.
Notice also that no trace of a time dilation factor is to be found in
Nu(o)/Nu = sqrt(fR * fS).

If a single SR formula is wrong, the whole theory is wrong, and
GR, from which SR can be derived, is logically also wrong.

The problem with SR/GRists is that most of them swallow all
what they find in textbooks, and consider their findings as
gospel truth.



Bye,
Bjoern

Marcel Luttgens

Marcel Luttgens wrote:
Bjoern Feuerbacher wrote in message ...

Marcel Luttgens wrote:

Bjoern Feuerbacher wrote in message ...



snip, because those points have already been discussed


But you should realize that light is not sound, because
of the speed limit c.

*sigh* Obviously. That's why one uses Nu(o) = Nu sqrt((1-v/c)/(1+v/c)),
not Nu(o) = Nu / (1+v/c), if you didn't notice.



No, those who use Nu(o) = Nu sqrt((1-v/c)/(1+v/c)) because of time dilation,
forget that in an expanding universe,

*sigh* For the 100th time: The Doppler shift formula of SR and LET,
Nu(o) = Nu sqrt((1-v/c)/(1+v/c), is *not* used in cosmology.



GR is used, but is GR right?

If you have evidence that it isn't, feel free to present it.

I notice that you did not care to admit that your assertion above
(the SR formula is used in cosmology) was wrong



No time dilation factor
is needed in an expanding universe, because the light source and the
observer are simultaneously receding wrt each other.

Irrespective of a time dilation factor is needed or not, your
formula above is simply wrong. If you think otherwise, present
a derivation which is *not* based on "the distance changes, but let's
consider that it it constant anyway".



IOW, you are saying that Nu(o) = Nu / (1+v/c) sould be used when
the light source is receding from the observer.

NO.

I say that for real movements, one should use Nu(o) = Nu
sqrt((1-v/c)/(1+v/c)) (regardless if the source or the observer is
moving, since motion is relative!), and in cosmology, one should use
1+z = R(t0)/R(t) for the red shift (reminder: R is the curvature
radius of the universe).



Yes, with many assumptions, like Omega M, flat universe, etc...

Wrong. Omega_M and the flatness of the universe are *measured*,
not assumed.


With some of those *needed* (should I say ad hoc?) assumptions,
GR gets about the same results as those obtained with a stable
universe and a "deceleration" cH.

Which *still* makes no sense at all.


Use Ted Wright's calculator if you are not yet convinced.

For the 10th time: I don't care about Wright's calculator.
Compare the predictions of your formula against the actual data!!!!!



But I don't understand what you mean by "real" movements. Are
movements in cosmology not "real"?

*sigh* I already explained that several times. That the distance
of galaxies increases is, according to GR, not due to a movement
of the galaxies, but due to the space between them expanding.


Nu(o) = Nu * (1-v/c) should also be used when the source is receding

from the observer, because light can be considered as a train of photons

of wavelength lambda emitted at c by the source. But as the source
is moving away at v, the frequency Nu(o) at which the photons are
emitted becomes Nu * (c-v)/c for the observer.

That claim is still utter nonsense.



Realize that, for the observer, the photons are not emitted at c,
but at c-v, by the atoms of the source.

No, that is utter nonsense. For the observer, the photons are emitted
at c, not at c-v. Both in SR and in LET.


I show hereafter that the SR formula Nu(o) = Nu sqrt((1-v/c)/(1+v/c))
cannot be right.

Unfortunately for you, it had been *tested* and *found* to be right.


[snip]



Thus, 1+z = = lambda(o)/lambda = (c+v)/(c-v), and
z = 2v/(c-v) = 2 v/c / (1-v/c),

which is the same formula as the one obtained with no time dilation!

Nice for you.

And now explain how this situation, where light is *reflected*, is
relevant for cosmology.


Because those two identical results show that something must
be wrong in the derivation of the SR formula

No, not at all. Why on earth do you think so?


Nu(o) = Nu sqrt((1-v/c)/(1+v/c))

Let's apply the sound Doppler to light:

1) The light source is receding at v from light the receiver

Then Nu(o)/Nu = c/(c+v), which leads to z = v/c.

Such formula is nonsensical for light, because with it, z can never be
greater than 1.

That formula is not nonsensical for light because z can never be
greater than 1, but because it was derived using assumptions which
are not valid for light.


Or galactic light can have much bigger redshifts than 1.

Huh?


Let fS = c/(c+v)

2) The receiver is receding at v from the emitter

Then Nu(o)/Nu = (c-v)/c, which leads to z = (v/c)/(1-v/c)

This formula gives sensible results.

The ultimate test if a formula gives sensible results is by
comparing it with experiment. For light, the formula fails then.


The same formula can be obtained when the source is moving
by hypothetising a stable universe where light is subject at
every point of its trajectory to a negative acceleration cH.

And how would that work?



And how, exactly, do you plan to derive this formula in that
case? I don't remember that you ever presented that calculation.


Notice that the reddening is then absolute, in the sense that
it is independent from observers.

Let fR = (c-v)/c

Now, the SR formula Nu(o) = Nu sqrt((1-v/c)/(1+v/c)), can be written

Nu(o) = Nu sqrt((c-v)/c) * c/(c+v)), or
Nu(o)/Nu = sqrt(fR * fS)

Nice.


The SR frequency ratio is simply the geometric mean of the frequency
ratio fR obtained when the receiver is receding and the frequency ratio
fS corresponding to the receding source!

Of the corresponding ratios obtained for *sound*.


Since fS is wrong for light, the SR formula must be wrong.

That's a *total* non sequitur.


Notice also that no trace of a time dilation factor is to be found in
Nu(o)/Nu = sqrt(fR * fS).

Err, when you write it in a way which does not show the time dilation
factor directly, it's no wonder that the time dilation factor is
not found in the formula, don't you think?


If a single SR formula is wrong,

*sigh* And you *still* ignore that this formula was *tested* and found
to be *right*.



[snip]

The problem with SR/GRists is that most of them swallow all
what they find in textbooks, and consider their findings as
gospel truth.

The problem with you is that you don't care about experimental
data and can't think logically.



Bye,
Bjoern