Re: Age of Star according to SR Question

Dirk Van de moortel wrote:
"Spoonfed" <good4usoul@xxxxxxxxx> wrote in message news:1147880095.102870.222440@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Peri of Pera wrote:
Spoonfed wrote:
Martin Hogbin wrote:
"Peri of Pera" <riedt1@xxxxxxxxxxx> wrote in message news:1147664233.281094.89390@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Dirk van der Mortel is unable to explain a question about the age of a
star.
Who can help? A star is measured by astronomers to be 10 billion years
old.
It is speeding away at .9c. What is the age of the star using the SR
time
dilation theory?

What is the point in asking someone to apply a particular theory
to something that is outside the scope of that theory?

Martin Hogbin

You are making assumptions about the scope of Special Relativity. I
can only guess what they are, and I'm not sure you're aware of your
assumptions or other possibilities. You may be assuming a flat
Friedmann model where redshift is not due to recession velocity and/or
you may be assuming a steady state universe, where everything was
always here, and in which local density fluctuations caused one galaxy
to form several billion years before ours.

IF you make such assumptions, then you could say that the age of such a
star is outside the scope of Special Relativity. But you should make
your assumptions clear, because Friedmann's Model has three options;
closed, flat, and open. Only one of them is correct, and unfortunately
the vast majority of work, education, and research is going to the flat
model, which is "the conservative bet" according to some, but is
actually quite misguided.

Spoonfed, I annoyed Dirk because I must have said something he didn't
like. Could he be the hijacker? What is his role in this NG?

Peter Riedt

No--it was just that I realized Tim and I had gone completely off the
topic of the star question. From what I can tell, Dirk and I
understand Special Relativity in just about the same way. And he's
willing to put the effort into explaining it as long as he thinks
you'll listen. But then if he does put in the effort, it's his pet
peeve if you just leave the thread dangling, and go posting the same or
similar question in another thread (which you did), he gets kind of
cranky. He takes his revenge by finding the stupidest thing you said
and immortalizing it on his website. He's fairly honest about it
though--he generally doesn't quote out of context.

There are several people that post on the newsgroup that really seem
bright enough to understand the theory but choose not to; repeating the
same thing time after time, and completely oblivious to the mistake
they are making even though it has been pointed out to them over and
over again, usually refusing to acknowledge even that anyone pointed
out the mistake. For me, Dirk performs a useful role by cataloguing
these posts so that I can distinguish between people who are completely
immune to logic, and people who might just be off the beaten path.

But on this specific topic of the current age of a distant object, Dirk
and I agreed to disagree some time ago.
http://groups.google.com/group/sci.physics.relativity/msg/cfc2edf4396876f5?&hl=en


And in so doing, I believe I also agreed to disagree with Gould, Baez,
Penrose, Hawking, John Nash, and most other famous physicists.
However, I was gratified to find Mike Fontenot in my court, who wrote a
paper on the Current Age of Distant Objects (CADO).
http://groups.google.com/group/sci.physics.relativity/msg/fb97d9745316a097?hl=en&;


The problem is, there's not much of an argument I can make against a
flat denial of the reality of the current age of a distant object. I
can point at a tree all day and say it's there, but a determined cynic
could develop all manner of argument to say that it's not. I have to
figure out why someone would think it was meaningless.

I believe it has to do with Alexander Friedmann's 1922 paper "Uber die
Krummung des Raumes" (Zeitscrhift fur Physik 10:377-86) which I
wouldn't be able to read even if I saw it. Somewhere in this paper,
Friedmann does a boundary value problem, solving the Einstein Field
Equations, and comes up with three classes of solutions for the
geometry of the universe. The classes are closed, flat, and open
models.

In the flat and closed models the scale factor can be a complex or
imaginary number. In such a model the current age of distant objects
would have no physical meaning so Dirk and all the others would be
right. But in the open model the scale factor is always a real
positive number and the current age of distant objects is a valid
quantity; then Mike Fontenot and I would be right. I am quite
convinced that the open model is the correct one but I'm not a
brilliant physicist. I'm just a guy with a fondness for real valued
distances.

But all this has nothing to do with open, flat or closed models, or
boundary value problems, or with field equations, or with scale
factors or complex or imaginary numbers. It also has also nothing
to do with you or Mike or me or the 'others' being right or wrong.
It was about the *uselessness* of the concept of "*now* in a
remote location as judged from an *accelerating* frame".
So you don't "have to figure out why someone would think it was
meaningless". We already agreed that it is not meaningless and
that it is "perfectly valid, as long as things are made explicit".
The concept is just useless because I can fiddle with the *now*
of the remote location by simply adjusting my thrusters.


YOU CAN FIDDLE WITH THE NOW OF THE REMOTE LOCATION BY ADJUSTING YOUR
THRUSTERS. What about this do you think is useless or meaningless?


Riedt pretended that he wanted to know about the simple case
of the age of a remote inertial object as seen from inertial frame.

By skill or by luck, it's still a good question. Some people need to
see several examples before they can understand things clearly.

He claims he knows better, but he can't even explain what it is
'that he knows better than'.

Riedt, what do you know better than?

The pig doesn't want to learn to sing. Pigs just snort and fart.

Dirk Vdm

.

Relevant Pages

  • Re: Age of Star according to SR Question
    ... A star is measured by astronomers to be 10 billion years ... What is the age of the star using the SR ... You may be assuming a flat ... I annoyed Dirk because I must have said something he didn't ...
    (sci.physics.relativity)
  • Re: Age of Star according to SR Question
    ... A star is measured by astronomers to be 10 billion years ... What is the age of the star using the SR ... You may be assuming a flat ... I annoyed Dirk because I must have said something he didn't ...
    (sci.physics.relativity)
  • Re: Age of Star according to SR Question
    ... A star is measured by astronomers to be 10 billion years ... What is the age of the star using the SR ... I annoyed Dirk because I must have said something he didn't ... paper on the Current Age of Distant Objects. ...
    (sci.physics.relativity)
  • Re: Age of Star according to SR Question
    ... A star is measured by astronomers to be 10 billion years ... What is the age of the star using the SR ... You may be assuming a flat ... I annoyed Dirk because I must have said something he didn't ...
    (sci.physics.relativity)
  • Re: Age of Star according to SR Question
    ... Dirk van der Mortel is unable to explain a question about the age of a ... A star is measured by astronomers to be 10 billion years ... What is the age of the star using the SR ... You may be assuming a flat ...
    (sci.physics.relativity)