Re: SR time dilation on remote objects ?
From: Bjoern Feuerbacher (feuerbac_at_thphys.uni-heidelberg.de)
Date: 09/06/04
- Next message: hanson: "Re: Al-Qaeda nukes real threat to USA"
- Previous message: o8TY: "Re: "Free shaves tomorrow" was: 57 Days and Counting....."
- In reply to: Marcel Luttgens: "Re: SR time dilation on remote objects ?"
- Next in thread: vonroach: "Re: SR time dilation on remote objects ?"
- Reply: vonroach: "Re: SR time dilation on remote objects ?"
- Reply: Marcel Luttgens: "Re: SR time dilation on remote objects ?"
- Messages sorted by: [ date ] [ thread ]
Date: Mon, 06 Sep 2004 18:00:14 +0200
Marcel Luttgens wrote:
> Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<ch9nmo$nnb$1@news.urz.uni-heidelberg.de>...
>
>>Marcel Luttgens wrote:
>>
>>>Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<ch79h0$6hd$1@news.urz.uni-heidelberg.de>...
>>>
>>>
>>>>Marcel Luttgens wrote:
>>>>
>>
>
> <ad hominem snipped>
What you term an "ad hominem" here was a list of your evasive
tactics. It's nice to see that even you yourself are so embarassed
about this that you had to snip the list entirely.
> I presume that you will disagree with the following
> quote.
Yes.
> I don't disclose the name of its author, because
> some mainstreamers could label him as a crank.
>
> "Something has gone wrong in the field of astronomy.
> Many widely held beliefs fly in the face of observational
> evidence. Theories go through such contortions to resolve
> inconsistencies that the ideas can no longer be explained
> in simple language.
That ideas in physics can not be explained any more in simply language
is not new. This has been so for at least 80 years (QM), or even
140 years (electrodynamics).
> Alternative ideas are often rejected
> out of hand simply because they challenge the status quo.
Example?
> Intuitively, most of us understand that an idea's popularity
> is no more an appropriate measure of its validity today
> than it has been at any other time in history. Yet those
> who question any widely accepted theories are labeled
> ignorant, and if they persist are branded cranks, charlatans,
> or worse."
They are labelled as cranks etc. not because they question these
theories, but in most cases because they show that they don't
even understand the theory they attack, don't know most of the
data for it, and refuse to learn.
>>Originally you said that the fact that our galaxy is almost as old
>>as the universe is a problem, since elliptical galaxies are assumed to
>>be older than spiral galaxies. But nothing what you quoted above
>>supported your claim that elliptical galaxies are older than spiral
>>galaxies. So your original argument is dead.
>>
>
>
> FRom http://galileo.as.utexas.edu/research_evolution.html
>
> "Morphological Evolution of Galaxies:
>
> Our study suggests that ~75% of the elliptical and S0 galaxies
> observed at present formed as such, while the remaining ~25%
> of these galaxies formed as spiral galaxies, and underwent
> morphological evolution, for all three cosmological models
> considered (the percentages might be smaller for elliptical
> than S0 galaxies). These numbers assume a morphological evolution
> process which converts one spiral galaxy into either a S0 or
> an elliptical galaxy. If the morphological evolution process
> involves mergers of spiral galaxies, these numbers be would
> closer to 85% and 15%, respectively. We conclude that most
> galaxies did not undergo morphological evolution, but a
> non-negligible fraction did."
>
> Note that some elliptical galaxies formed from spiral
> galaxies, hence they must be older.
Err, if the elliptical galaxies formed from spiral galaxies, then
obviously the *spiral* galaxies must be older, not the elliptical
ones, as you claimed above!
> Some of those elliptical galaxies probably evolved from spiral
> galaxies as old as our Milky way, hence they should be older
> than the universe.
Do you want to say that when the spiral galaxy turned into a
elliptical galaxy, it was already as old as the Milky Way is today,
and since then, another 10 billion years or so passed? If yes, how on
earth did you get this idea from the quote above?????
>>You have not shown to have a clue of the current theories of galaxy
>>formation. If you show that you have read relevant papers and are aware
>>of the models and assumptions used, I will apologize to you. But
>>probably this won't happen before hell freezes.
>>
>
>
> See above, but you don't need to apologize.
The quote above does contradict you, not support you.
Have you severe reading comprehension problems?
>>>>That would explain two different groups, but not a line with a rather
>>>>good correlation coefficient.
>>>
>>>
>>>See astro-ph/0404207
>>
>>Why don't you address the fact that there is indeed a line with a rather
>>good correlation coefficient, instead of going to yet another paper?
Hello? Why don't you address that?
>>>"From abstract:
>>>
>>>Supernovae Ia (SNe Ia) light curves have been used to prove
>>>the universe is expanding. As standard candles, SNe Ia appear
>>>to indicate the rate of expansion has increased in the past
>>>and is now decreasing. This independent evaluation of SNe Ia
>>>light curves demonstrates a Malmquist Type II bias exists
>>>in the body of supernova data. If this bias is properly addressed,
>>>there is very little budget for time dilation in the light
>>>curves of supernova.
>>
>>This has been discussed on the badastronomy.com bulleting board.
>><http://www.badastronomy.com/phpBB/viewtopic.php?p=227836&highlight=malmquist+bias+supernova&sid=dc9b062af8a301dd9f0be4c7a6c78c10#227836>
>>The author did not bother to substantiate his claims in any way there.
>>Perhaps he is related to you?
>
>
> He must be a crank.
Close to. At least he *tries* to look at the evidence, in contrast
to you.
>>Also, I wonder why the data obtained from the supernovae for both the
>>Hubble parameter and the cosmological constant agree so well with other,
>>independent methods of determinations of these parameters, if there is
>>something sooo seriously wrong with them. Just plain luck yet again, eh?
I notice that you yet again simply choose to ignore such arguments.
>>>>From page 4:
>>>
>>>The ‘Stretch factor method relies upon a free parameter to
>>>associate the magnitude of the light curve with the light
>>>curve width. There are at least four potential flaws in these
>>>analyses:
>>>
>>>1) A correction is made for redshift before other potentially
>>>distance biasing effects are addressed.
>>
>>Why is that a problem?
Care to answer that?
>>>2) The sample is normalize at a reference value midway between
>>>local and distant supernova. Any linear distance dependencies
>>>are buried by this technique.
>>
>>What dependencies, and why are they buried by that?
And that?
>>>3) The ‘free parameter‘ is unique to each supernova and assumes
>>>no lateral variance in origin.
>>
>>I assume that he talks about the parameter s here. The analysis showed
>>that this parameter is, within the error margins, constant.
And comment on that?
>>>4) No allowance is made for a Malmquist type II bias"
>>
>>I fail to see how that bias could influence the results, and the author
>>did not bother to explain that at the badastronomy.com bulletin board, too.
>>
>
>
> Many opinions can be found in the badastronomy.com bulletin board,
> some of which are clearly against time dilation on SN, for instance
*sigh* And yet again, instead of sticking to the paper at hand, you
go to another source!!!
> http://www.badastronomy.com/phpBB/viewtopic.php?p=255612&highlight=malmquist+bias+supernova#255612
>
> Post from John Kierein
> Posted: Fri May 07, 2004 11:54 pm Post subject: SN 1A Time Dilation
>
> --------------------------------------------------------------------------------
>
> "I have returned from the American Physical Society's astrophysics
> meeting in Denver. I attended a talk where supernova -in particular,
> SN 1A, - time dilation evidence was discussed in great detail.
> The upshot is that the speaker, Jerry W. Jensen, said there is
> no such evidence. "
Err, this Mr. Jerry W. Jensen is exactly the one who wrote the paper
you cited above, if you did not notice.
> "He showed that there is a well observed relation between the time
> length of the SN 1A curve and the brightness of the SN, with the
> brighter SN having longer light curves. He showed that the selection
> effect should be that the brighter SN 1A should be preferentially
> observed at the greater Z of greater distance simply because
> it is brighter. He used terms such as the previos author (Goldhaber)
> not making allowance for Malmquist bias. Basically his argument was
> (as I understand it), that the brighter SN have an intrinsically
> longer light curve and they should show up more than the dimmer
> SN at larger red shift and that the data from his analysis shows
> not only that time dilation cannot be claimed but that actually
> THERE IS NO TIME DILATION!"
And I see that you conveniently ignore the post just a little
but downwards, by Cougar, Sat May 08, 2004 12:48 am, which says:
"John Kierein wrote:
...He showed that there is a well observed relation between the time
length of the SN 1A curve and the brightness of the SN, with the
brighter SN having longer light curves.
Of course this was first pointed out in 1993 by Mark Phillips in a paper
that enabled Type Ia supernovas to serve as standard candles. Phillips
demonstrated beyond reasonable doubt that there is a correlation between
the peak luminosity of a Type Ia supernova and the rate the brightness
declines. More luminous Type Ia's fade more slowly than less luminous ones."
So this effect has long been known and taken into account in the
supernova analysis. Mr. Jensen apparently does either not know this,
or refuses to acknowledge this.
> Of course, Jerry W. Jensen must be a crank,
In light of what has been pointed out just above, he is very close to
being one, yes.
> as well as the many
> scientists who signed the statement at
> http://www.cosmologystatement.org/
I know that statement very well, and not surprisingly, it includes many
people who have railed long against the BBT. And e.g. Lerner *is*
a crank - for example, he is not above misrepresenting papers which
support the BBT as refuting the BBT.
> <snip>
>
>>I see that you *still* do not bother to explain that.
You *still* have not explained why there is a good correlation
coefficient. Merely claiming that there are two different populations
1) is an unsupported, baseless assertion
2) does not explain why there is such a good correlation coefficient
3) does not explain why even inside the two groups, there is a clear
upward trend
>>>>>>>>I explained already several times that this method to calculate the
>>>>>>>>acceleration due to gravity makes no sense (for starters, it gives no
>>>>>>>>uniquely defined gravitational field!), and that in a homogeneous
>>>>>>>>universe, the acceleration due to gravity is *zero* everywhere. You can
>>>>>>>>see this by using the formula
>>>>>>>>g = G int dV' rho(r') (r-r')/|r-r'|^3.
>>>>>>
>>>>>>Do you claim that this formula is wrong? Or that applying it to a
>>>>>>homogeneous universe would not give zero?
>>>>>>
>
>
> No.
No to which of the two questions?
> It is indeed wiser to only consider a universe with a very big, but
> not infinite, radius.
So you claim that the universe is only finitely large? If yes, what
shape do you propose for it? Apparently a filled sphere with only
empty space surrounding it, or what?
BTW, the formula above can also be implied to a finite universe (a
closed universe; although one has to pay a bit more care there than
in the case of a flat universe), and then it *also* says that the
acceleration due to gravity is zero (if the density is homogeneous).
>>>Let's consider an imaginary stable spherical universe of mean density rho
>>>and radius R.
>>
>>Such a universe would not be a homogeneous and isotropic 3D space, hence
>>anything you derive for it is entirely irrelevant for the *real*
>>universe.
>
>
> No, because:
>
> In such universe, the Cosmological Principle, according to
> which the universe, when viewed on sufficiently large distance
> scales, has no preferred directions or preferred places,
> applies.
A universe which is shaped as a sphere with a finite radius R does *has*
preferred places. It does *not* look the same everywhere. For starters,
it does look quite different at its boundaries than at its center!!!
> IOW, the observer can be situated anywhere in the
> the universe, hence any of its points should be considered
> as a center,
Not if the universe is finite.
> because only from a center would the universe appears
> homogeneous and isotropic.
That statement makes no sense.
>>BTW, how *could* such a universe be stable? You yourself say that there
>>is a gravitational acceleration, so it can't be stable!!!
>>
>
>
> This problem was resolved long ago by Einstein with his cosmological
> constant (now renamed dark energy).
The cosmological constant is a parameter in the equations of GR. So you
can derive your model from the equations of GR? Feel free to show the
calculations.
If you can't do that, then it makes no sense for you to incorporate the
cosmological constant in your model.
[snip]
>>>My approach doesn't lead to a multiple gravitational field.
>>
>>I did not say that it leads to a multiple gravitational field. I said
>>that it leads to a gravitational field which is not uniquely defined. The
>>gravitational field one obtains depends on the point one chooses to be
>>the center.
>
>
> Why should it be uniquely defined?
Oh my goodness. Do you *really* think a universe in which the
acceleration due to gravity depends on who calculates it makes sense?
> According to the Cosmological
> Principle, the universe has the same properties for all observers,
> whatever their position.
And this principle contradicts a finite universe shaped as a filled
sphere.
>>Answer my question: if one uses your approach, what about the
>>gravitational forces coming from the matter *outside* the sphere you
>>"isolated"?
>
>
> Already Newton knew that the outside matter has no effect.
*sigh* That is true only if the matter outside has a spherically
symmetric distribution. What's your basis for assuming that?
>>>>>>>The proof of the pudding is in the eating. How do you explain that
>>>>>>>my "false premise" leads to d = (c/H) * z/(1+z), which is exactly
>>>>>>>the same formula as the purely *kinematic* Doppler formula valid in an
>>>>>>>expanding universe?
>>>>>>
>>>>>>Please give me a reference saying that this formula is used in the
>>>>>>standard model of cosmology. I strongly doubt that this is true.
>>>>>>
>>>>>
>>>>>
>>>>>It is certainly not used in the standard model, but it is valid for
>>>>>an expanding universe with no observable time "dilation".
>>>>
>>>>Please prove this assertion.
>>>
>>>
>>>1 + z = 1 / (1-v/c),
>>
>>Why should this formula hold? Looks a bit like a Doppler shift formula -
>>but unfortunately for you it is not the *right* formula for the Doppler
>>shift...
>>
>
>
> The naive Doppler shift z = v/c cannot be used, because v = cz leads
> to velocities greater than c when z > 1.
What you call the "naive Doppler shift" is actually an approximation
of the *real* formula, which is valid only for v << c. No wonder that it
does not work for large v...
> The simplest way to avoid this nonsense is to use the formula
> z = (v/c) / (1-(v/c)).
Where did you get this formula from? Can you give *any* physical
arguments why it should hold?
Why don't you use the Doppler shift formula of Special Relativity?
[snip]
>>>>>Otoh, my "false premise" also leads to H.
>>>>
>>>>Huh? Do you claim you can predict the numerical value of H?
>>>>
>>>
>>>
>>>Of course, as I get the relation a = [(4/3)*G*pi*rho]*d = K^2 * d,
>>>where K^2 is also the formula giving H^2.
>>
>>Huh? K^2 is not a formula, it is an expression. What on earth do
>>you mean?
>
>
> The expression is the same for K^2 and H^2, thus, mathematically,
> a = H^2 * d
So you say that H^2 = 4/3 * G * pi * rho?
This is rather close to the formula used in cosmology:
H^2 = 8/3 * G * pi *rho_crit,
with the *critical* density.
>>And what do you insert for rho here?
>>
>
>
> The present density of the universe.
And where do you get a number for this from?
>>>>From page 12 of Goldhaber et al.'s paper:
>>>
>>>"Fits to Figure 3 (a) and (b) yield different information.
>>>The linear fit shown in Figure 3(a) has dw/dz = 1.07 ±0.06. If there
>>>were no z dependence in w this slope would be 0, here assuming no
>>>evolutionary change in s. Hence the evidence for the presence of a
>>>1 + z factor is 1.07/0.06 ≈18 standard deviations.
>>>Figure 3(b) shows a slope ds/dz = 0.05 ±0.05."
>>
>>Your point? They did say nowhere that they used a linear regression
>>analysis. Answer my question: why do you think that a simple linear
>>regression analysis makes sense for those data?
>>
>
>
> A slope is the trigonometric tangent of the positive angle formed
> between a given straight line and the x-axis of a pair of
> Cartesian coordinates. Notice "a given straight line".
<
> As Goldhaber et al. say that Figure 3(b) shows a slope
> ds/dz = 0.05 ±0.05, I infer that they used a *linear* regression
> analysis.
That's a completely unwarranted conclusion. A linear regression
analysis is by far not the only method to get a line which best fits the
data. In fact, it is a rather clumsy method, which, as I pointed out
repeatedly, can not take the measurement errors of the data into account.
Also, Goldhaber et al. got a different result for the slope than both
you and me when we did a linear regression analysis. Don't you think
that that fact shows nicely that they did *not* do a linear regression
analysis, but something different?
For the third time, at least: Why do you think that a simple linear
regression analysis makes sense for those data?
>>>Did you notice that 0.05/0.05 = 1 standard deviation?
>>
>>Yes.
>>
>>
>>
>>>No serious scientist would consider this as statistically
>>>significative.
>>
>>*sigh* Could you please tell me why the bad statistical results
>>for s do in any way invalidate the *good* statistical results
>>they obtained for w, which was the crucial point of the paper?
>>
>
>
> Their *good* results result from a systematic error, due to the
> neglect of the Malmquist bias.
As is explained in detail on the badastronomy.com bulletin board,
this bias has been known since 1993, and is taken into account.
*If* there really is a systematic error, then why is the correlation
coefficient so good? Pure luck, eh?
Bye,
Bjoern
- Next message: hanson: "Re: Al-Qaeda nukes real threat to USA"
- Previous message: o8TY: "Re: "Free shaves tomorrow" was: 57 Days and Counting....."
- In reply to: Marcel Luttgens: "Re: SR time dilation on remote objects ?"
- Next in thread: vonroach: "Re: SR time dilation on remote objects ?"
- Reply: vonroach: "Re: SR time dilation on remote objects ?"
- Reply: Marcel Luttgens: "Re: SR time dilation on remote objects ?"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
