UV Galaxy Surface brightness says no expansion

In summary, this paper discusses the Tolman Surface Brightness Test for the reality of the expanding universe model. It argues that the test is inadequate and that further evidence is necessary to support the model.
  • #1
CarlB
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Claims universe not expanding:
http://www.arxiv.org/abs/astro-ph/0509611

Another recent article about redshifts being apparently wrong:

Research on candidates for non-cosmological redshifts
"The paradox of apparent optical associations of galaxies with very different redshifts, the so-called anomalous redshift problem, is around 35 years old, but is still without a clear solution and is surprisingly ignored by most of the astronomical community. Statistical correlations among the positions of these galaxies have been pointed out by several authors. Gravitational lensing by dark matter has been proposed as the cause of these correlations, although this seems to be insufficient to explain them and does not work at all for correlations with the brightest and nearest galaxies. Some of these cases may be just fortuitous associations in which background objects are close in the sky to a foreground galaxy, although the statistical mean correlations remain to be explained and some lone objects have very small probabilities of being a projection of background objects.
The sample of discordant redshift associations given in Arp's atlas is indeed quite large, and most of the objects remain to be analysed thoroughly. For about 5 years, we have been running a project to observe some of these cases in detail, and some new anomalies have been added to those already known; For instance, in some exotic configurations such as NGC 7603 or NEQ3, which can even show bridges connecting four object with very different redshifts. Not only QSOs but also emission-line galaxies in general are found to take part in this kind of event. Other cases are analyzed: MCG 7-25-46, GC 0248+430, B2 1637+29, VV172 and Stephan's Quintet."
http://www.arxiv.org/abs/astro-ph/0509630

Comments?

Carl
 
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  • #2
As far as I know there are three phenomena directly related to expansion: redshift, Tolman’s surface brightness test and cosmological time dilation. Any static model must fit with all three and struggle against an overwhelming number of observations which support expansion. I cannot estimate the quality of the first paper, but I would like to know whether it is (or will be) published in any journal besides of the “Proceedings of the First Crisis in Cosmology Conference”.
 
  • #3
Definitely a minority opinion, Carl. Don't even get me started on Arp. His 'freak' catalogue of galaxies is a 'handwaving' exercise. Arp has a grudge, and has commercially exploited it with his bogus books. He cherry picks evidence supporting his pseudo-science and ignores the rest. An arxiv paper that vaguely supports his views does not constitute clear and convincing evidence. I can cite dozens of arxiv papers that blow Arp's baloney right out of the skillet, if desired. My advice - steer clear of crackpot sites.
 
  • #4
Wait a minute Chronos - the OP paper is Lerner not Arp and he is describing further observational evidence that claims to contradict the FRW expanding universe model.

Instead of writing it off without any other consideration, for the sake of good scientific practice, we should at least see if his understanding of FRW models and their predictions is correct, whether the observations he cites can be substantiated and whether they are actually inconsistent with those models.

I am studying his paper at the moment and already I have one or two questions about it, I'll get back soon, meanwhile does anybody else have considered criticism of Lerner's paper?

Garth
 
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  • #5
Well there is this other paper on today's arXiv A large population of galaxies 9 to 12 billion years back in the history of the Universe.
To understand the evolution of galaxies, we need to know as accurately as possible how many galaxies were present in the Universe at different epochs. Galaxies in the young Universe have hitherto mainly been identified using their expected optical colours, but this leaves open the possibility that a significant population remains undetected because their colours are the result of a complex mix of stars, gas, dust or active galactic nuclei. Here we report the results of a flux-limited I-band survey of galaxies at look-back times of 9 to 12 billion years. We find 970 galaxies with spectroscopic redshifts between 1.4 and 5. This population is 1.6 to 6.2 times larger than previous estimates, with the difference increasing towards brighter magnitudes. Strong ultraviolet continua (in the rest frame of the galaxies) indicate vigorous star formation rates of more than 10 to 100 solar masses per year. As a consequence, the cosmic star formation rate is higher than previously measured at redshifts of 3 to 4.
So they seem to be describing the same effect, though using a different data set, but explaining it as an enhanced star formation period in the early universe. That makes sense to me.

Garth
 
  • #6
Agreed, Garth. It was late and I was hasty. I need to reread the paper to see what other options he has in mind. Anyways, To understand Lerner's point, I recommend this series of papers by Alan Sandage:

The Tolman Surface Brightness Test for the Reality of the Expansion. IV. A Measurement of the Tolman Signal and the Luminosity Evolution of Early-Type Galaxies
http://arxiv.org/abs/astro-ph/0106566
http://arxiv.org/abs/astro-ph/0106563
http://arxiv.org/abs/astro-ph/0102214
http://arxiv.org/abs/astro-ph/0102213
 
  • #7
Garth said:

thanks for flagging that one Garth. It seems like a good find----published in Nature (a good sign yes?) I read as much as I could understand at one sitting and it made sense. A lot of UV (around 1500-2500 angstrom) light coming from galaxies with z = 1.4 to 5 indicates rapid star formation. And there would have to be rapid star formation if there were going to be lots of galaxies in the early universe. I'm heading for bed and this will give me something to dream about----ancient galaxies busily forming stars.
 
  • #9
Finally got around to reading Eric J. Lerner's paper mentioned in the OP.

Learner seems to have done a good job of putting together a good paper. I did not find any sloppy treatment of data or his analysis. Priori assumptions and selections of variables seem reasonable and objective. There are no unexplained 'leaps', as I call them, of logic or of hope and faith seen in so many papers.

The postulate of 'Evidence for a Non-Expanding Universe' is based on the comparison of FRW prediction of redshift (z+1^3) relation to surface brightness; measured in the UV range the relation turns out to be z+1^0.83, according to Lerner in section 3, last sentence, (the pages are not numbered). In my studies, FRW does not provide much foundation for the relationship of redshift to galaxy surface brightness, it is one of those things that seemed to 'fit' at the time.

Lerner mentions several instances where data compatible with his view has been explained away with the waving of hands and an attitude of "let's not open this can of worms because we don't have a solid case and if we attack FRW we are going to be ridiculed".

I personally have no problem with the idea that z needs a better foundation than Hubble gave it. There is getting to be a rising tide of questions about it, I say good. I've read all I could find on the history of Hubble's Parameter and tests of it over many years; there is, in my mind, sufficient doubt to warrant a directed effort to better understand redshift and in general do a lot more observational work on stellar distance measurement. Surface Brightness, Luminosity, Lensing, Background Projection, etc. all have very significant error bars.

Lerner's view of Expansion is clearly not the only view that could be seen in the recent data, but I would certainly not discount it. His paper deserves reading.
 
  • #10
kublai said:
I personally have no problem with the idea that z needs a better foundation than Hubble gave it. There is getting to be a rising tide of questions about it, I say good. I've read all I could find on the history of Hubble's Parameter and tests of it over many years; there is, in my mind, sufficient doubt to warrant a directed effort to better understand redshift and in general do a lot more observational work on stellar distance measurement. Surface Brightness, Luminosity, Lensing, Background Projection, etc. all have very significant error bars.
Please be aware that the Hubble was not very comfortable with the idea that redshift is due to cosmological expansion. He established a general relationship between the distances of objects and their redshifts. Where possible, he used "standard candles" like cepheid variables, and as he studied more and more distant objects and the "standard candles" became harder to measure reliably or were entirely unavailable, he and his cohorts (Halton Arp among them) had to resort to things like relating surface brightness, galaxy morphology and angular size to estimate the distances. These fellows did the tough observational work and established a general realationship between distance and redshift. It was cosmological theorists that seized this relationship and proclaimed that the Universe is expanding.

It is not surprising that Arp accumulated so many odd galaxies and clusters of galaxies odd morphologies, many apparently interacting, but with redshifts that (if interpreted strictly as cosmological distance) would make such interactions impossible. Whenever he made such observations, the Big Bang crowd routinely dismissed them as "selection error", "chance alignment", etc, etc, and ultimately shunned him when he refused to toe the BB orthodox line. It's too bad that theorists get to control the money and the telescope time of observational astronomers who make observations that conflict with their theories. Arp was a top-notch observer, and like Hubble he refused to believe that cosmological expansion was the only possible explanation for the redshift relationship they so painstakingly produced.

Interestingly, every single one of Arp's observations of interaction between objects with discordant redshifts is rejected by the BB adherents for one reason or another. This is because if even one of them is real, the BB is in trouble. Conversely, the discovery of the CMB (one data point!) is routinely touted as "proof" of the correctness of the BB theory, both in the press and in textbooks. Statements such as that are patently dishonest. Here are a couple of reasons:

1) Gamow's most refined prediction at the time of Penzias and Wilson's discovery was too high by over an order of magnitude. Eddington and others had been predicting a temperature of "empty" space calculated from the EM flux of all visible glowing "stuff" going back into the 1800's. Predictions of 3-7 degrees absolute were the norm, and Eddington's calculation was at the low end of this range, VERY close to today's accepted value. Gamow predicted 50 degrees and then puffed out his chest and crowed when he was proven wrong, claiming success.

2) Even if Gamow had been right (or even close!), agreement with one observation (a single data point) does not "prove" a model. The correct temperature had also been predicted by many physicists using non-expanding models of the universe, and many of these predictions were far more accurate than Gamow's. Is Eddington's steady state model "proven" because he accurately predicted the temperature of the CMB? Of course not, and neither is the BB, despite the routine indoctrination foisted upon aspiring astronomers/cosmologists today.
 
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  • #11
Be also aware that Lerner is not exactly reknowned in the physics community. Historically, he is math challenged, but, talks a mean 'plasma physics' and 'tired light' theory [see Ned Wright's site for discussion]. I'm not going to butt heads again with turbo over Arp. He admires Arp. I think Arp is a crackpot.

I think it is very disengenuous to suggest Eddington has any claim to having 'predicted' the CMB temperature. He even admitted his basis for 'predicting' a background temperature was fundamentally flawed. And so were his premises for predicting a steady state universe. Gamow, while predicting the wrong 'temperature' [based on a very inaccurate approximation of the Hubble flow], was wrong for the right reasons. But his basis for predicting the CMB existed was very correct.
 
  • #12
Chronos said:
Be also aware that Lerner is not exactly reknowned in the physics community. Historically, he is math challenged, but, talks a mean 'plasma physics' and 'tired light' theory [see Ned Wright's site for discussion]. I'm not going to butt heads again with turbo over Arp. He admires Arp. I think Arp is a crackpot.
You're right. I do admire Halton Arp. He has the discipline and the persistence to make routine observations over and over again, and when he makes observations that conflict with the concordance view that all redshift is cosmological, he publishes those results. Hubble would have been proud of his perserverence and his honesty.

You call him a "crackpot" and accuse him of holding a grudge. If you see his work through the filter of the peer group of "concordance cosmologists" (think Junior High, folks), you will get an extremely negative slant on his work. If you will look at the work that he did with Hubble, especially the observations relating galaxy morphology, surface brightness, and angular size to the distance-redshift relationship, you will understand that Arp is a disciplined, skilled observational astronomer.

Observation is reality. Theory can approximate reality to the extent in that it can remain consistent with observation. A REAL theory can distinguish itself by making predictions that can be confirmed with observation. The adherents of the BB theory dodge and backfill relentlessly while not offering any falsifiable predictions. This is not healthy.
 
  • #13
CarlB said:
Claims universe not expanding:
http://www.arxiv.org/abs/astro-ph/0509611

I took a brief glance at this paper. It just blows my mind that this guy is trying to compare Lyman Break Galaxies to a local population. These things are thought to be vigorously star forming, probably well in excess of anything seen locally. That they would have much higher surface brightnesses is no surprise at all.
 
  • #14
turbo-1 said:
Even if Gamow had been right (or even close!), agreement with one observation (a single data point) does not "prove" a model.

Single data point? Alright, let's step through this. As you understand it, how is the CMB used to constrain cosmology? We can see whether or not your arguments are fair.
 
  • #15
while on the subject of crackpots...

Immanuel Velikovsky, friend of einstien, heretic scholar

http://www.thunderbolts.info/velikovsky-ghost.htm

the relevence being the reference to Arp, Lerner and "the big bang that can't be fixed"

http://www.thunderbolts.info/tpod/2005/arch05/050401sofar.htm

For me personally it was while reading Velikovsky as a youngter not so long ago that opened my eyes up to the revisionist history of old world myths in light of current cosmological "truths" especially with me being polynesian and all

...as you were
 
  • #16
Agreed, I consider Arp a crackpot... right up there with Flanders and Beardon... He writes junk populist books filled with errors, has a website to promote them, ignores inconvenient facts, is severely math challenged, and whines like a beaten puppy when criticized.
 
  • #17
SpaceTiger said:
Single data point? Alright, let's step through this. As you understand it, how is the CMB used to constrain cosmology? We can see whether or not your arguments are fair.
Turbo-1 here. First off, I apologize for the change in my user name. I moved recently and had to change ISP's and I neglected to edit my user profile accordingly. Apparently, it was time to update my password, and I never got the notification (my fault entirely!). I have tried to get my password reset for the past couple of days to no avail, so I have created an alter-ego until this can be sorted out. Temporarily I am Turbot - an unattractive creature with an optimistic outlook - always looking up! :rofl:

Anyway, my point was that no single observation or prediction can "prove" a scientific model. This is a fallacy. A model can be falsified by a single observation incontrovertably contradicting a prediction, but it cannot be proven by a single correct one. Despite this, many well-meaning people cite Penzias and Wilson's discovery of the CMB as the pivotal observation that "proved" BB and killed Steady State. A typical example is this:

New Wright's cosmology tutorial said:
The cosmic microwave background (CMB) is a key prediction of the hot Big Bang model, and the most important observation that discriminates between the Big Bang and the Steady State models. So it is an interesting historical anomaly that this prediction was not put forward and tested by the inventors of either theory, and that the first observers of the CMB were completely unaware of its cosmological significance.

Statements such as this are mere cheerleading for the home team, and defy the scientific method. No single accurate prediction can prove a model. Physicists and astronomers had been predicting for 60 years previous to Gamow that "empty" space would have a base temperature that can be calculated by adding the impinging energy flux from all visible sources. Typical predictions ranged from about about 3-7 deg K. Contrary to what Dr. Wright states in his wonderful tutorial, the observation of a background temperature of 2.7 deg K in no way falsifies Steady State and in no way differentiates that model from BB, except that Gamow's most refined prediction of the afterglow of the BB was over an OOM too hot.

http://www.dfi.uem.br/~macedane/history_of_2.7k.html

By the time that Penzias and Wilson made their discovery, Gamow had refined his prediction of the CMB to 50 deg K, over 10 times the observed temperature. This observation of the CMB did not "prove" the correctness of the BB, nor did it prove the correctness of the Steady State model. No single correct prediction can prove a model. The observation of the CMB could in no way falsify SS, since the correct background temperatures had been predicted for ovre 60 years under that model, and at best it could constrain Gamow's Hot Big Bang and force him to reconsider the temperature of the BB afterglow. Gamow very quickly ratcheted his temperature estimate back close to the measured value and claimed that he had correctly predicted the CMB.

Penzias said:
At the 4th "Texas" Symposium on Relativistic Astrophysics, George Gamow was the chairman of the session on Microwave Background Radiation. He ended his remarks with a comment which, to the best of my recollection, went, "If I lose a nickel, and someone finds a nickel, I can’t prove that it’s my nickel. Still, I lost a nickel just where they found one."
The "nickel" comment is a reference to Gamow's earliest prediction of 5 deg K. Unfortunately, the truth is that Pensias and Wilson found a few pennies where he "lost" a half-dollar.
 
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  • #18
Turbot said:
Anyway, my point was that no single observation or prediction can "prove" a scientific model. This is a fallacy. A model can be falsified by a single observation incontrovertably contradicting a prediction, but it cannot be proven by a single correct one. Despite this, many well-meaning people cite Penzias and Wilson's discovery of the CMB as the pivotal observation that "proved" BB and killed Steady State.

Whether or not you consider the discovery of the CMB to be the death of the steady-state universe is not important anymore. Why? Because further analysis of the information contained within the CMB has provided us with many, many more data points about the state of our universe. The standard model predicted the CMB power spectrum to very high precision, including all of the detailed structure of the acoustic peaks and the accompanying polarization spectrum. This (along with many other reasons) is why a modern astronomer would laugh at you if you suggested that the universe was not expanding, not just because of the discovery of the CMB.
 
  • #19
SpaceTiger said:
Whether or not you consider the discovery of the CMB to be the death of the steady-state universe is not important anymore. Why? Because further analysis of the information contained within the CMB has provided us with many, many more data points about the state of our universe. The standard model predicted the CMB power spectrum to very high precision, including all of the detailed structure of the acoustic peaks and the accompanying polarization spectrum. This (along with many other reasons) is why a modern astronomer would laugh at you if you suggested that the universe was not expanding, not just because of the discovery of the CMB.
Can you explain why further refinements of CMB measurements refute the Steady State theory?

Can you demonstrate how early predictions of the BB model regarding the future measurements of the CMB have validated the BB model? Please cite pre-COBE sources that predict the strong dipole anisotropy and the various multipole anisotropies. I expect that you will have a wealth of references and I eagerly await them.
 
  • #20
Turbot said:
Can you explain why further refinements of CMB measurements refute the Steady State theory?

To my knowledge, there is no theory of CMB anisotropies in a steady state cosmology, but if you have something that suggests otherwise, I'd be happy to look at it.
Can you demonstrate how early predictions of the BB model regarding the future measurements of the CMB have validated the BB model?

Of course. The basic structure of the CMB power spectrum was predicted back in the late 60s and early 70s. An excellent paper on the subject is

http://adsabs.harvard.edu/cgi-bin/n...pe=HTML&format=&high=43485695fb16147"

Here you'll see basic predictions concerning acoustic oscillations in the baryon-photon fluid (see, in particular, page 831). Residuals are expected from the Sachs-Wolfe effect; that is, doppler shifts from photons climbing in and out of potential wells. Even the smaller-scale peaks (detected first by WMAP) are mentioned here.

More precise predictions were made later as the cosmological parameters were measured via other means. This includes the supernova results (for dark energy), large scale structure measurements (for [itex]\Omega_m[/itex]), and nucleosynthesis calculations ([itex]\Omega_b[/itex]). The WMAP team then did a fit to the CMB power spectrum, considering a variety of cosmological parameters, and lo and behold, the best-fit parameters matched those measured by other means. The CMB is much more than evidence for an expanding universe, it's evidence for dark matter and dark energy as well.

The volume of references on this subject is enormous and I think you'll have to be more specific in your request (or do the search yourself). Several of things I've mentioned are already referenced in the "Classic Papers" sticky, so that's a good place to start.
 
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  • #21
SpaceTiger said:
To my knowledge, there is no theory of CMB anisotropies in a steady state cosmology, but if you have something that suggests otherwise, I'd be happy to look at it.
I asked you to show some predictions of the CMB anisotropies in BB cosmology. If you can do so, I will be happy to review them. If the BB cosmology has only "retrodictions" (yeah, we can explain that!) we should aknowledge that and recognize the weakness.
 
  • #22
Turbot said:
I asked you to show some predictions of the CMB anisotropies in BB cosmology. If you can do so, I will be happy to review them. If the BB cosmology has only "retrodictions" (yeah, we can explain that!) we should aknowledge that and recognize the weakness.

Uhh...did you read the paper I referenced? You do know that 1970 was before COBE, right? What about the WMAP paper? Do you understand why that constitutes a "prediction" and not a "retrodiction"? This stuff is pretty basic, turbo.
 
  • #23
Chronos said:
Agreed, I consider Arp a crackpot... right up there with Flanders and Beardon... He writes junk populist books filled with errors, has a website to promote them, ignores inconvenient facts, is severely math challenged, and whines like a beaten puppy when criticized.
Your rantings against Arp are insulting and are uncalled-for. He is one of the most skilled observational astronomers of our time. His observations relating galaxy morphology and brightness were instrumental in the development of Hubble's redshift/distance relationship. When you have compiled a body of work comparable to his, you can challenge his findings. Even then (slim chance!), you are not worthy to insult him and call him names.
 
  • #24
SpaceTiger said:
Uhh...did you read the paper I referenced? You do know that 1970 was before COBE, right? What about the WMAP paper? Do you understand why that constitutes a "prediction" and not a "retrodiction"? This stuff is pretty basic, turbo.
I asked you to provide early predictions from BB adherents regarding the CMB that support the BB and invalidate Steady State cosmology. Still waiting...

I welcome early BB predictions of the CMB dipole and mutipole anisotropies and small-angle anisotropies.

If small-angle anisotropies are not consistent between WMAP1 and WMAP2 data realeases, the CMB must be local and not cosmological. Want to place a wager on this?
 
  • #25
Turbot said:
I asked you to provide early predictions from BB adherents regarding the CMB that support the BB and invalidate Steady State cosmology. Still waiting...

Which part of this didn't you understand:

Of course. The basic structure of the CMB power spectrum was predicted back in the late 60s and early 70s. An excellent paper on the subject is

Peebles & Yu 1970

Here are some more along the same lines, though the above paper should be more than enough.

http://adsabs.harvard.edu/cgi-bin/n...pe=HTML&format=&high=43485695fb23914"
http://adsabs.harvard.edu/cgi-bin/n...pe=HTML&format=&high=43485695fb23914"
http://adsabs.harvard.edu/cgi-bin/n...pe=HTML&format=&high=43485695fb24550"
http://adsabs.harvard.edu/cgi-bin/n...pe=HTML&format=&high=43485695fb24781"
 
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  • #26
Turbot said:
Your rantings against Arp are insulting and are uncalled-for. He is one of the most skilled observational astronomers of our time. His observations relating galaxy morphology and brightness were instrumental in the development of Hubble's redshift/distance relationship. When you have compiled a body of work comparable to his, you can challenge his findings. Even then (slim chance!), you are not worthy to insult him and call him names.
My 'ranting' against Arp is based upon his undisciplined, reckless disregard for evidence that does not fit his belief system. Even worse, he appears incapable of admitting he has ever made a mistake. I'm not the one challenging his 'findings'. I'm the jury, not the prosecutor. And the prosecution has made a very strong case, IMO.
 
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  • #27
SpaceTiger said:
Thank you for the list, though if I ever have time to read "War and Peace" (Peebles and Yu) fully, I will be surprised.

In the abstract (I haven't found the derivation in the over-800-page paper) Peebles and Yu predict small-angle fluctuations of at least 150ppm. WMAP is showing us fluctuations of only about 10ppm, correct? Also, shouldn't the CMB's blackbody shape be smeared out due to redshift differentials from the beginning of recombination until the end of recombination?
 
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  • #28
Turbot said:
Thank you for the list, though if I ever have time to read "War and Peace" (Peebles and Yu) fully, I will be surprised.

You don't have to read and understand the entire thing to figure out that it constitutes a prediction of the spectrum of CMB anisotropies. At minimum, you can just skip to page 831 and read the section on the CMB. Really, though, 22 pages is not all that long for a paper of this sort.


In the abstract (I haven't found the derivation in the over-800-page paper)

Hmm...interesting. Is it possible that you never actually looked at the paper? Reason I ask is that the only explanation for why you would think it was over 800 pages long is that I referred you to "page 831". That's page number actually refers to the page in the journal, not the paper itself. The paper itself is only 22 pages long.


Peebles and Yu predict small-angle fluctuations of at least 150ppm. WMAP is showing us fluctuations of only about 10ppm, correct?

That's correct. Can you think of why the discrepancy might arise? (Hint: what cosmology are they assuming?)

This paper only represents an interesting prediction of the shape of the power spectrum, not its normalization. The magnitude of the fluctuations was more accurately predicted later by some of the other papers I cited (which were still pre-COBE).


Also, shouldn't the CMB's blackbody shape be smeared out due to redshift differentials from the beginning of recombination until the end of recombination?

Remember that the temperature goes as (1+z) both before and after recombination, so if one part of the universe decouples at z ~1000, while another part does so at z~1200, the present-day CMB will still have the same temperature in both parts.
 
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  • #29
SpaceTiger said:
Hmm...interesting. Is it possible that you never actually looked at the paper? Reason I ask is that the only explanation for why you would think it was over 800 pages long is that I referred you to "page 831". That's page number actually refers to the page in the journal, not the paper itself. The paper itself is only 22 pages long.
I could not get the paper to download from the harvard service over my (VERY slow) dial-up (even though due to very slow download speeds, I let my browser go for a VERY long time!), but I did get to read a page-by-page GIF version with pagination that was ran into the 800's, which is why I thought your original link was to a monster paper - perhaps a whole journal or something. I still didn't find what I was looking for, although the authors made the assumption that the primordial artifacts hadn't been smoothed by later interaction, which would lead to larger-than-expected deltaT/T anisotropies. This seemed interesting, since their era of interest ranges from 10000K to 2500K, seemingly with lots of opportunity for interaction.

What I've taken from Hu's paper on polarization, though seems to assume many layers of interaction, with the measurable polarization effects (~1 ppm level) comprising a very small part of the signal, and resulting from interaction with only the last surface of the reionization era.
 
  • #30
Turbot said:
I still didn't find what I was looking for, although the authors made the assumption that the primordial artifacts hadn't been smoothed by later interaction, which would lead to larger-than-expected deltaT/T anisotropies.

The main reason they overpredicted the fluctuations was actually their lack of dark matter. Notice that they considered a flat universe with only photons and baryons. If one instead considers a flat universe dominated by photons and dark matter (with a small fraction of baryons), can you see why the level of fluctuations would be brought down significantly? Dark matter doesn't actually interact with the photons, so it can't oscillate in the same way that the baryons do.

In other words, they considered roughly the same amount of matter as we do now, but didn't consider that most of it was out of equilibrium with the photons.
 
  • #31
I dont' see the point in talking about what happened to photons before the last surface of scattering of CMB photons. They have no effect on CMBR studies, aside from contributing to the power spectrum.
 

1. What is UV Galaxy Surface brightness and how does it relate to expansion?

UV Galaxy Surface brightness is a measure of the amount of ultraviolet light emitted from a galaxy's surface. It is not directly related to the expansion of the universe, but it can provide valuable information about the properties and evolution of galaxies.

2. Why does UV Galaxy Surface brightness suggest no expansion?

UV Galaxy Surface brightness does not suggest no expansion. It is simply a measurement of the amount of ultraviolet light emitted from a galaxy's surface. Other measurements and observations, such as the redshift of distant galaxies, provide evidence for the expansion of the universe.

3. How can we determine the expansion rate of the universe?

The expansion rate of the universe can be determined through various methods, such as measuring the redshift of distant galaxies, observing the cosmic microwave background radiation, and studying the properties of supernovae. These methods all provide evidence for the expansion of the universe.

4. Is there any evidence to support the idea that the universe is not expanding?

There is overwhelming evidence from various observations and measurements that support the idea of the expansion of the universe. These include the redshift of distant galaxies, the cosmic microwave background radiation, and the observed distribution and movement of galaxies in the universe.

5. Can UV Galaxy Surface brightness be used to study the expansion of the universe?

No, UV Galaxy Surface brightness is not directly related to the expansion of the universe. However, it can provide valuable information about the properties and evolution of galaxies, which can contribute to our understanding of the universe as a whole.

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