Re: SR time dilation on remote objects ?

From: Marcel Luttgens (mluttgens_at_wanadoo.fr)
Date: 07/08/04 

Date: 8 Jul 2004 07:21:52 -0700

Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<cch5qa$3eb$1@news.urz.uni-heidelberg.de>...
> Marcel Luttgens wrote:
> > Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<cce69c$816$1@news.urz.uni-heidelberg.de>...
> >
> >>Marcel Luttgens wrote:
> >>
> >>>Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<ccbt41$gor$1@news.urz.uni-heidelberg.de>...
> >>>
> >>>
> >>>>Marcel Luttgens wrote:
> >>>>
> >>>>
> >>>>>SR time dilation on remote objects ?
> >>>
> >>>
> >>>A remark to all GRists:
> >>>
> >>>Instead of quibbling about formulae incorporating the "assumed"
> >>>space expansion, (pseudo-)cosmologists should better give their opinion
> >>>about
> >>>
> >>>The "Triplets" thought experiment (Adapted from the "Twin paradox")
> >>
> >>Why? It is irrelevant for the cosmological time dilation.
> >
> >
> > Why is it irrelevant?
>
> Because you keep acting as if the cosmological time dilation had
> to do something with the velocity.
> >
> > Are not remote galaxies receeding from
> > Earth with some velocity, which is a function of their distance?
> > Is such velocity only "apparent", Iow not real?
>
> I already told you that the recession of the galaxies is due to
> the space between them and us expanding.
>

Meaning that they are receeding form us at some velocity, which is
a function of their distance.

>
> > If it is a mere
> > illusion, how do you explain the Doppler shift?
>
> The red shift is not a Doppler shift - it occurs due to the expansion
> pf space. I already told you that, too - didn't you listen, or have you
> forgotten that already?
>

Is not the velocity of expansion expressed in the equation
 v = Hr, in which v is velocity, r is distance between two points.
What are those points, if not, for instance, the Earth and a galaxy?
H is related to the density of the universe, meaning that its value
varies if the universe is expanding (This doesn't mean that H was
infinite when (?) the BB took place).

>
> > And if it is real (for those believing in expansion of course,
> > I have to dot the i's), and some galaxy at distance d from Earth
> > moves at v wrt the Earth, does not the Earth moves at the same
> > velocity wrt the galaxy?
>
> Seen from that galaxy, the Earth seems to move at the
> same speed (but obviously in the opposite direction).
>

I would delete the restriction "seems".

>
> > For an Earth observer, is not the time
> > on the galaxy slowed down by some factor wrt the time on Earth?
>
> The time *seems* to have moved slower when the light we observe now on
> Earth left that galaxy.
>
>
> > And for the galactic observer, is not time on Earth slowed
> > down by the same factor wrt its own time?
>
> The time *seems* to have moved slower when the light they observe now on
> in that galaxy left the Earth.
>
>
> > Does this not logically
> > mean that the Earth clock and the galactic clock tick at the same
> > rate,
>
> No, not at all. Why on earth do you think so?
>

Those SR/GRists (seemingly all of them), who don't understand
simple logic could read and comment this little tale:

5 years old's twin logic
________________________

After many months of sunless weather, Terra and Galaxy are
equally pale. Their mother decides that they need to stay
a week at a sunny southern beach.

The fourth day after their arrival, Terra says to Galaxy:
"How suntanned are you! I am sure that you are darker than me!".
And Galaxy replies: "You too are darker than me!".

Their mother then said: "Yes, you are both darker than 4 days
ago, but your colour is exactly the same. None of you is darker
than the other.
Your logic is similar to that of cosmologists, who claim, like
Brian J. Barris et al. in arXiv: astro- ph/ 0310843 v1 29 Oct 2003:

"Typically, the discovery epoch of a high-z supernova
is a few days before maximum brightness, and although
the time dilation factor of (1 + z) works to lessen
the delay in the rest frame, etc...".

Your error is understandable, you are only 5 years old, but
contemporary cosmologists's deficient logic can only
be explained by the persistency of magical thinking. You will find
such persistency in astrology, big bang theory, relativity
theory, voodoo, etc...".

>
> > as confirmed by Terence in the "Triplets thought experiment"?
>
> That thought experiment confirms nothing like that.
>
>
> > As both clocks tick at the same rate,
>
> Now they do. When the light left the source, the clocks seem
> to have ticked at a different rate than they now do.
>

Sure, what is your point?

>
> > how can the contemporary
> > cosmologists claim that a time dilation factor of (1 + z) works
> > on supernovae to lessen the delay in the rest frame?
>
> Drop the rhetoric and look at the actual calculations.
>
>
> > I am looking forward to reading your comments.
>
> I am looking forward to you misunderstanding them yet again.
>
>
>
> >>>"Terence sits at home on Earth. Galaxy (yes, it's her name)
> >>>flies off in a space ship at a velocity v/2. Simultaneously,
> >>>Terra (also a name) flies off in the opposite direction at -v/2.
> >>>After a while, Terra, who considers that Galaxy flies away
> >>>from her at a velocity v,
> >>
> >>Why should Terra consider that? Does she not know how to
> >>add velocities in SR?
> >>
> >
> >
> > You don't seem to grasp the spirit of Terra's claim, which
> > is that Galaxy is flying away from her at some velocity.
>
> We are talking about measurements here, not about "spirit".
>

As you like.

>
> >>>claims that Galaxy is now younger
> >>>than her, exactly like GRists claim that time goes slower on
> >>>SN because of space expansion.
> >>
> >>That is in no way "exactly like".
> >>
> >
> >
> > Don't GRists make such claim? Remove "exactly" if you prefer.
>
> GR say that time seems to have gone slower on the SN when the
> light was emitted. Not that *today*, time *still* goes slower on the SN.
>

What GRists infer and claim is a time slowing on SR wrt to Earth time.
This is illogical, as the reciprocal is true.

>
>
> >>>According to Terence, both Terra and the GRists are wrong,
> >>
> >>There *is* no "right" or "wrong" here. Who is younger depends
> >>on the frame of reference. There is no "absolute time".
> >>
> >
> >
> > This is trivial.
>
> Then why do you say something nonsensical like "both Terra and
> the GRists are wrong"?
>

Terra ignores that Galaxy keeps the same age as her. The GRists think
that time goes slower on supernovae wrt time on Earth, forgetting that
time on Earth goes slower, at the same rate, wrt time on supernovae.
The only logical conclusion is that no time effect can be observed from
Earth on SN.

I leave now, because I cannot repeat the same refutations ad nauseam.
You "seem" to reason like Terra and Galaxy in the little tale above.
And you don't "seem" to be able to understand its meaning.

[snip]

>
> Bye,
> Bjoern

Marcel Luttgens

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