Re: SR time dilation on remote objects ?

From: Bjoern Feuerbacher (feuerbac_at_thphys.uni-heidelberg.de)
Date: 08/09/04 

Date: Mon, 09 Aug 2004 15:14:03 +0200

Marcel Luttgens wrote:
> Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<ceqahd$f84$1@news.urz.uni-heidelberg.de>...
>
>>Sorry for the late reply - I was on holiday for a week...
>>
>
>
> We are going round in circles.

Yes. Because you are ignoring my argument.

> Here is the summary I told you about.
>
> FALSIFYING SR

[snip]

How often do I need to tell you that I wish to concentrate
on cosmology before going to any other topics?

> Aplication to an expanding universe:
> ___________________________________
>
> In such universe, observers A and B separated by a distance d move
> *from each other* at a velocity v, which is a function of d.

And of time, if you didn't notice.

> It has been shown above that *in such situation*, A and B clocks
> tick at the same rate.

Your demonstration about SR is entirely irrelevant here.

In cosmology, the relevant formula for time dilation is:
   dt(when the light was emitted) = f*dt(when the light is observed).
You claim that you can show that f = 1 - but for showing that, you
use an argument which seems to be based on
   dt(A) = f*dt(B) and dt(B) = f*dt(A),
completely ignoring the *crucial* difference between the time when
the light as emitted and the time when it was observed.

I told you that about 5 times now. You *still* ignore that.

> Applying SR, observer A situated at a distance d from observer B
> will claim that tB = tA * sqrt(1-v^2/c^2), but, in his frame of
> reference, observer B is perfectly right (sic) to claim that
> tB = tA * sqrt(1-v^2/c^2)!

Using tB and tA here makes no sense, because
1) time dilation applies to time *intervals*, so you should write
dt or delta t or something like that.
2) you *still* ignore the *crucial* difference between the time when
the light as emitted and the time when it was observed.

[snip]

> - According to an article published in 1999 by © CAMBRIDGE UNIVERSITY
> PRESS (THE ORIGIN OF THE REDSHIFT, see
> http://nedwww.ipac.caltech.edu/level5/Peacock/Peacock3_3.html ):
>
> "For small redshifts, the interpretation of the redshift as
> a Doppler shift (z = v / c) is quite clear. What is not so clear
> is what to do when the redshift becomes large. A common but
> incorrect approach is to use the special-relativistic Doppler
> formula and write
> 1 + z = sqrt((1+v/c)/(1-v/c))
> This would be appropriate in the case of a model with Omega = 0,
> but is wrong in general."

Completely agreed.

> In fact, it is *never appropriate* to use the special-relativistic
> Doppler formula,

It is.

> because expansion cannot have a decelable SR effect,

Nonsense.

> as clocks keep ticking at the same rate.

Wrong.

> Only a kinematic Doppler redshift can be observed.
> The error made by contemporary cosmologists is due to their
> blind faith in SR, leading them to believe in the so-called
> mutual time dilation.

For the 20th time: time dilation in cosmology has nothing to do
with time dilation in SR!!!

[snip remainder]

When will you *finally* stop ignoring my main argument?

Bye,
Bjoern

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