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

Marcel Luttgens wrote:

Bjoern Feuerbacher wrote in message ...


Marcel Luttgens wrote:


SR time dilation on remote objects ?

Question:

Can time be "SR dilated" on remote galaxies or supernovae, because
of space expansion?

No. Apparent time dilation due to space expansion has nothing to
do with the time dilation of SR.



What do you mean by "apparent"? Is it such time expansion or not?

I don't know what you mean by "time expansion".



From the context, I clearly meant "time dilation". Now you could perhaps
explain what you mean by "apparent".

According to the Robertson-Walker metric, the "rate" of time was
always the same. But the expansion of the universe "stretches" the light
we receive from objects which are far away (and therefore light which
left these objects long ago), and this makes it look like as if time
went slower back then.


Anyhow, explaining the assumed time dilation by SR or by GR doesn't
change the fact the space expansion acts symmetrically,

What on earth is that supposed to mean?



Did you sleep enough last night? Bist du nicht ein bischen müde?

Evasion noted. Why don't you simply answer the question?

And why did you feel the need to try to write German here?



meaning that somebody on Earth *cannot* observe such dilation.

Why on earth do you think so?


Because A claims that the time on B moving away from him is dilated,
and B symmetrically claims that time on A is dilated wrt its own time.

Right for SR time dilation, wrong for the apparent time dilation
due to space expansion.


As both are simultaneously right, the only logical conclusion is that
the two time dilations cancel each other.

Absolute total utter non sequitur. Why is this "logical"??? How could
such a cancellation happen?????


But as a SR/GRist, you prefer to believe (yes, "believe") that both
are right.

Err, you said two, above, that both are right.


What a disastrous conclusion!

Why?

You seem to have a big problem with the concept that time is relative...


Claiming
that space expansion gives a time dilation redshift is simply wrong.

Only a Doppler shift can be observed.

You have never actually seen the calculations, right?



A hopeless argument. You are incorrigible.

That was a question, not an argument.

Evasion noted.

Did you ever see the calculations or not?


Details are given hereafter, as well as the refusal by the
moderator to post my question in sci.physics.research

Perhaps because you could read this up yourself if you would
bother to actually open a book on cosmology? I recommend
"The early universe" by Kolb&Turner.



This is a good example of crooked debating.

It is "crooked debating" to tell you that you miss the basic knowledge
about this topic, and provide a reference where you can read it up???



Again and again the same ad hominem ...


Pointing out that you lack the basic knowledge is not an ad hominem.




I am not "saying that contemporary cosmology and GR are fundamentally
wrong", I prove it.

You prove nothing like that. You even don't know what modern
cosmology says. E.g., you didn't know that the Hubble parameter
is time dependent even during quite ordinary expansion!



The Hubble constant is determined by the mean density of the
universe. Instead of just claiming that it is time dependent,

Err, didn't you notice that due to expansion, the mean density
of the universe is obviously time-dependent, and therefore according
to your own argument here, the Hubble parameter has to be
time-dependent, too?



For the expansion proponents, it is of course time dependent,

Nice that you admit that. In some earlier postings, you acted as
if you don't not that.


but even
for them, it is *to-day* determined by the mean density of the universe.

I said nothing against that.



you should better show the formula,

The formulas are there in any book on cosmology. Try looking into them.



I preferred your own formulae. With GR, according to the assumed
premises, one can say almost anything.

Nonsense.


Further, for a particular model, I once wrote down the calculations
myself. The text is in German, but the formulas should be clear enough.
http://www.rzuser.uni-heidelberg.de/~bfeuerba/universum.pdf
The formulas there are for an accelerated universe (with cosmological
constant different from zero), but it's not hard to take the limit
of cosmological constant going to zero, and the result is that H then
still depends on t (hint: the result of taking the limit is H(t) =
2/(3t) - and that's a formula you can find in lots of books on cosmology).



Thank you. Of course, H depends historically on t, as the mean density
of the universe varies with t if the universe is expanding (with an
"apparent" ;-) velocity).

If this is so clear to you, then why did you act as if you don't know
that?



and simultaneously explain why the
assumed space expansion is not symmetrical for all observers.

I don't understand what you mean by "symmetrical" here, sorry.



Not yet?

No.

Next evasion noted.



Why don't you allow experts to disprove my
demonstration?

Because they have better things to do than to correct your
elementary misconceptions about the Big Bang theory?



The Big Bangers are those which are full of misconceptions.

Says the one who did not even know that H depends on t during
ordinary expansion...



What a bad faith!

Huh? You acted several times as if you don't know that H is time-dependent.



The BB theory is riddled with ad hoc patches.

For example? (I expect now that you will mention inflation, dark
matter and dark energy - thus displaying that you have no clue of
the evidence for that stuff, and of the reasons why it was introduced)



Ad hoc inflation,

See my note in the parentheses...


large scale structures,

What is ad hoce about them???


accelerated expansion,

See my note in the parentheses...



usw... Please remind me why dark energy has been introduced.

Because of a variety of reasons. You seem to think that there
was only one...



Bye,
Bjoern