Talk:György Paál

Problematic synthesis, reliance on primary sources

I have removed a couple of things from the article that were clearly wrong:

• Claim that György Paál was the first to propose a nonzero cosmological constant, in 1992. In reality, Einstein had already proposed this in 1917 when he came up with the idea. You can find papers from any decade since then that propose a nonzero cosmological constant. The source cited is a primary source, a paper by Paal himself, which does not claim to have been the first proposal of a nonzero cosmological constant. This claim is therefore both unsourced and obviously incorrect.
• Juxtaposition of Paal with papers by Perlmutter et al., Riess et al. This is unacceptable WP:SYNTH because it implies that there is a connection between Paal's papers and the discovery of accelerating expansion several years later. This is not the case. Paal's paper has nothing to do with the discovery of dark energy, and the papers by Perlmutter et al. and Riess et al. certainly make no mention of Paal. This is exactly the kind of thing that the Wikipedia synthesis policy was designed to avoid: it combines individually correct elements in such a way as to advance a position that is not supported by the sources. In the absence of secondary sources, it certainly must go.

Outside those two items, the rest of the article is largely based on primary sources in a way that's still problematic, although perhaps not clearly wrong. --Amble (talk) 01:13, 29 June 2012 (UTC)

OK Amble. Let's move our discussion from Talk:Dark_energy to here. Give me some time to read the Wikipedia policy in English. Please, do not be angry if you have to write me something twice to really understand what does it mean. Until then, please read more details in this article, which was written by one of Paal's coauthor. Kozmokonstans (talk) 08:58, 29 June 2012 (UTC)

Thanks. I will take a look at the article by one of the coauthors. --Amble (talk) 14:08, 29 June 2012 (UTC)

Weighing in on this with some specific comments (I agree with Amble's comments above and at Dark Energy on Wiki policy and lack of secondary sources), Paál et al.'s papers relied on an apparent periodicity in the redshift distribution of some surveys. Such periodicity does not appear in more complete, large area surveys. Paál's conclusions ("nontrivial topology, fundamental cell ..., present inflation ..., Lambda > 0) thus depend on a set of observational assumptions that are now known to be incorrect. Thus, although this paper does propose a non-zero cosmological constant, the foundation of that proposal is incorrect. Amble has given citations to even earlier work proposing Lambda > 0 from observations, and those papers also depended on data that is now understood to be incomplete and/or incorrect. That's why such earlier works are not cited as the first observational discoveries of dark energy, whereas the supernova results, which have held up under further scrutiny, are. - Parejkoj (talk) 15:48, 29 June 2012 (UTC)

Dear Parejkoj. Not to misunderstand me I would like to take some statements. I am not saying that wrong scientists received the Nobel prize. Also not saying that those Hungarians should receive it. But I am saying that SCP and HZT made a very good and important discovery. Surely worth to get the Nobel prize. And they were the first scientists who convince the community to consider seriously as a fact that the cosmological constant is non zero. However, there were some previous research, just like in the History of Lorentz transformations. Lorentz discovered the transformations and we called them after him. However as Hermann Minkowski said in 1908 that the transformations which play the main role in the principle of relativity were first examined by Voigt in 1887.

In the mentioned paper written by Paal's coauthor, Horvath wrote "Paal wanted to find out whether the regularity found in the galaxy distribution is quasiperiodical or not." The mathematics does not change if one think different background philosophy. Paal et al. used real data and ask a question there is another cosmological model where the quasiperiodicity is better. They found cosmologies where the observed data significantly had better quasiperiodicity. One can think the cause of this quasiperiodicity. Paal thought the reason was periodicity (please, realize this is the first time I write the word periodicity), so the Universe has nontrivial topology i.e. periodical in some way. The mathematics in their paper did not need this periodical Universe idea. Paal had been thinking about this idea (the Universe has nontrivial topology) since his 1971 paper. But the mathematics and to get the best cosmological model and to get significance does not need philosophy. Actually, does not need any cause. The statement that there are cosmological models where the observed data have significantly better quasiperiodicity is a mathematical statement. This statement does not need even any physics.

And of course these better cosmological models need non zero cosmological constant. If you study the figure of Holba et al. which is also included in the mentioned Horvath paper the confidence region in the figure is very similar compare with the supernovae result. The paper mention a www page for this comparison. This similarity is not surprising. Since we have only one Universe to observe. And I believe this unique Universe has only one geometry ;-). Therefore, if one uses observations from the same physical thing (here is our Universe) it is not surprising all analysis suggest similar results.

Finally, of course the physical cause (or philosophy) of the quasiperiodicity (if there is any) should be explained. But this is another thing. One can think lots of ideas. I think you are right that the periodical or quasiperiodical Universe model is not true in our Universe. But one can think about BAO as a cause of the observed quasiperiodicity. Also I am open about for other different ideas ;-). Kozmokonstans (talk) 04:50, 30 June 2012 (UTC)

Ahoj! I am waiting for your opinion. Kozmokonstans (talk) 05:00, 5 July 2012 (UTC)

As far as I can see from the sources, the papers of Paal et al. depend entirely on the existence of (quasi-) periodicity. Take that away, and they have no evidence for a cosmological constant. That's the substantive reason why I don't agree with linking his group to the discovery of dark energy. There's also the reason grounded in Wikipedia policy, which is perhaps more important and doesn't really depend on the substance of the papers. That simply goes back to the overreliance on primary sources and lack of independent sources. --Amble (talk) 08:21, 5 July 2012 (UTC)

Well. This is not true. Have you heard about BAO? Kozmokonstans (talk) 08:03, 22 November 2013 (UTC)

Sure. Do you have a source linking BAO to the (quasi-) periodicity claimed by Paal? --Amble (talk) 08:21, 22 November 2013 (UTC)

Thanks for your answer. However, I do not understand why does one need source for 1+1=2? I mean for the mathematics of Paal's papers one does not need philosophy or explanation. The pencil beam observation suggested small number galaxies big number galaxies, small number galaxies big number galaxies, etc. One do not need periodical universe or BAO to explain this. One point of those papers do not need explanation.

Simply; one can ask is there any cosmological model where this strange behavior (quasi periodicity) gets better. The answer was yes. And surprise Lambda (2/3) was the best. Since we observe only one Universe, we expect all observation suggest similar parameters. My point is Paal at al. used observed data. Calculated something and they got Lambda. However, you are right those paper major point was the periodical universe. But the Lambda needed statement stands without any topological assumptions. Kozmokonstans (talk) 15:20, 22 November 2013 (UTC)

Lambda in Paal's papers

Generally I agree we need secondary sources. However in this special case the abstract of those papers wrote:

Inflation and compactification from galaxy redshifts:

"... and Lambda greater than 0" and "positive Lambda term is indicated"

and Cosmological parameters and redshift periodicity

"fitting to the previous optimum at Omega(0) equals 1/3, and lambda(0) equals 2/3."

I do not think one need to has independent source to be sure these papers wrote in their abstracts those papers got Lambda in cosmology. Kozmokonstans (talk) 15:34, 22 November 2013 (UTC)

You need independent and secondary sources to show whether this work by Paal is accepted in the field as significant and correct. --Amble (talk) 15:44, 22 November 2013 (UTC)

Sorry, but you are not helping. Please, help to push the discussion where at least we can agree. I never said it is significant. But I say it is correct. You are right. To prove it was significant one need secondary sources. But I never said this. To prove it is correct one does not need secondary sources. Do you agree? Have you ever published scientific paper? I mean if yes, it would be easier to continue the discussion. Otherwise I may need to explain what is scientific research and scientific result. However, thank you very much for your answers. Kozmokonstans (talk) 16:13, 22 November 2013 (UTC)

I'm sorry, but I can't really help you if what you're trying to do is contrary to basic principles of Wikipedia. It doesn't matter one bit whether I've published scientific papers. What's needed here is really pretty simple: we must understand WP:PRIMARY. If you want to link BAO to Paal's claimed (quasi-) periodicity, you need sources to establish that connection. Otherwise, you're engaging in impermissible original synthesis. This is the opposite of a special case; it's a perfect example of why the rule is needed. --Amble (talk) 16:25, 22 November 2013 (UTC)

No, I do not want to link BAO. That is my point. One does not need BAO or periodicity. The mathematics stands alone. I do not synthesize. I do not add anything to their papers. Once again: I just read the abstract. What is your problem the statements in their abstracts? Do we need independent source to understand they wrote "lambda(0) equals 2/3"? Thank you for your patience. I am going to read again your WP links. Kozmokonstans (talk) 16:36, 22 November 2013 (UTC)

If you don't want to make a connection with BAO, then why did you bring it up in the first place? I could argue with you about your reading of Paal's paper itself, but I'm not going to do that because it simply doesn't matter. Wikipedia doesn't allow you to use your own interpretation of primary sources in this way. --Amble (talk) 16:50, 22 November 2013 (UTC)

Look, if we are not agree, that is bad. Not very bad for you, since you will delete any of my edits :-( What you just write is not true. But I do not want to do this circle again. This is not my interpretation. I am sorry you think that.

Another approach: If I understand correctly the secondary sources paragraph statement: Secondary sources are not necessarily independent or third-party sources. The mentioned 2012 paper is secondary source. Am I right? Kozmokonstans (talk) 17:05, 22 November 2013 (UTC)

The 2012 paper does look like a secondary source, but frankly not a very strong one. Among other things, it exists only as an unreviewed preprint; it's not independent; and there's no sign that the basic argument has gotten any traction with anyone besides the author. It also doesn't support the connection you've sometimes made to BAO, or your claim that (quasi-) periodicity isn't needed for the results claimed in the 1992 papers to be meaningful. --Amble (talk) 20:08, 22 November 2013 (UTC)

Given my current editing habits I'm not all that likely to delete anything. But I suspect other editors may agree with my assessment. --Amble (talk) 21:34, 22 November 2013 (UTC)

Thank you for your answer. Now we are getting somewhere ;-) May I add a couple of useful information:

1, Now the secondary source is a reviewed article. (google is our friend ;-)

2, The Paal's papers did have independent citations. Not much, but they had.

- The G. Paál, I. Horváth and B. Lukács, App. and SS, (191) (1992), 107. received two independent citations.

- The A. Holba, I. Horváth, B. Lukács and G. Paál, App. and SS, (222) (1994), 65. received four independent citations. Kozmokonstans (talk) 09:58, 23 November 2013 (UTC)

Yeah, that's a really weak citation record and ADTI is a brand-new open access publication with no established reputation. For the most part, such journals will publish anything with little or no real review. (The low standard even of copy editing on the journal's website also does not inspire confidence.) I guess I also have to say again that the one secondary source you're using doesn't even support the claims you have made. --Amble (talk) 16:54, 23 November 2013 (UTC)

As I said, I'm not really likely to be able to put much time into editing here. I've requested additional opinions at WT:PHYSICS. --Amble (talk) 16:59, 23 November 2013 (UTC)

Additional opinion: in order to get credit for a physical hypothesis, the underlying theory generally has to be correct. There is no evidence for periodicity in quasar or galaxy redshifts, so Paal's idea is incorrect on its face. It is also essentially uncited outside the original research group, and the "open access journal" your review was published in made a list of Predatory Publishers; not much of an endorsement! Checking above, apparently I had the same thoughts a year and a half ago (July 2012). Kozmokonstans: you are definitely pushing WP:SYNTH here, particularly when you brought up BAO above. - Parejkoj (talk) 19:12, 24 November 2013 (UTC)

I mostly agree (except the pushing part). 1, The Predatory Publisher argument is correct and I just had found out this a day before you wrote here. 2, BAO was an example not an argument. Please, do not argue with an example. Actually, just forget about BAO. I will not mention it again. So I think I am not pushing anything. The pure mathematics of Paal's papers stands alone without any assumptions. However, I already wrote this. It is sad I could not convince you. Since I do not want to repeat myself this is the end. We do not agree. And we do not have to (but would be better :-). Kozmokonstans (talk) 07:19, 25 November 2013 (UTC)

I agree: "The pure mathematics of Paal's papers stands alone without any assumptions."

They used observed data.

The chi2 got better.

Their preferred universe model is a Universe with Lambda! --Squrry41 (talk) 18:09, 14 September 2022 (UTC)

Parejkoj

Without discussion Parejkoj deleted half of the article. Why? 14:10, 24 November 2023 (UTC) Katkahosz (talk) 14:10, 24 November 2023 (UTC)

see https://ui.adsabs.harvard.edu/abs/2016Univ....2...23D/abstract — Preceding unsigned comment added by Katkahosz (talk • contribs) 14:14, 24 November 2023 (UTC)

Is there a source which prove, that Paál's model was incorrect? I revert your delete, since you deleted half of the articles, which contains sources. --Katkahosz (talk) 12:12, 1 December 2023 (UTC)

Removed it again: this model got basically no citations in the mainstream, in large part because it's so wrong there's no reason to respond. It's not clear why Debono & Smoot (2016) cites Paál et al. (1992): it's just a passing citation with no relevance to the surrounding text, and there are many better citations they could have used to discuss the cosmological tensions in the 90s. That's the only citation to Paál's quasar work outside of other fringe-y papers. It's just not notable. - Parejkoj (talk) 18:44, 1 December 2023 (UTC)

You are wrong!

First; before revert my edit you have to discuss it. You have not done it, so please revert back yours until we do not have a conclusion.

Second; wikipedia does not care about what you have stated. You have to have a scientific citation, that Paal's calculation is wrong. Stay with the facts! Fats in science what is published in a referred journal.

Third; you without any thinking deleted my new edit too. Do not do this, please!

Please, have discussion in wikipedia! --Katkahosz (talk) 06:49, 2 December 2023 (UTC)

Please read WP:BRD (we're doing the Discussion part now), WP:FRINGE (Paál's work is entirely fringe), WP:N (Paál's work is not notable within astronomy and cosmology, as demonstrated by its not being cited), and even WP:NPROF (Paál himself does not appear to be particularly notable). On the latter point: I'm not sure Paál even passes the academic notability criteria: his ADS listing shows few papers and none with any significant citations. His work is fringe, and has been ignored by the field. There are no secondary sources discussing Paál's work, and it is obviously incorrect on its face given what we know now about the distribution of galaxies and quasars. - Parejkoj (talk) 19:50, 2 December 2023 (UTC)

Hi! Thank you for having a discussion. First, I do not like to discuss the topology of the Universe (i.e. periodicity). I am only talking about the Lambda (cosmological constant). Paal's works calculated the value, which happen to have close to the accepted one.

1, Paal published a paper about Lambda. They calculated the value.

2, There is no paper which wrote the mathematics of their calculation was wrong.

3, I collected some citation in a separate section here. --Katkahosz (talk) 09:54, 3 December 2023 (UTC)

Paal published Lambda value and some work quoted it

Please, give some scientific work, which prove or claim that the Paal’s calculation was wrong.

I give citations, which referred Paal’s work. Not just ADS collects papers, however as one can see, there are other citations in ADS, too.

Paal’s work was cited also by books. For example;

A Theory of Unified Gravitation By Gil Raviv (2010), ISBN: 9780615342030.

Citations from articles

1, K N P, KUMAR ; B S, KIRANAGI AND C S, BAGEWADI: Dark energy and expanding Universe. International Journal of Scientific and Research Publications, 2 : 6 p. 1 , 27 p. (2012) „The first paper, using observed data, which claimed a positive Lambda term was G. Paal et al. (1992). Inflation and compactification from galaxy redshifts?. ApSS 191: 107–24.Bibcode 1992Ap&SS.191..107P. doi:10.1007/BF00644200.”

2, Tank, HK: Four alternative possibilities that the universe may not be expanding. Adv. Studies Theor. Phys., Vol. 7, 2013, no. 18, 867 – 872. “If the expansion of the universe is accelerating, as the current interpretation of the observations suggest [1,2,3], then very large amount of dark-energy may be needed (68.3 % of total) for the closer-density.” [1] Paal, G. et al. (1992) ApSS 191: 107–24 [2] Adam G. Riess et al. (1998) Astronomical J. 116 (3): 1009–38 [3] Perlmutter, S. et al (1999) Astrophysical Journal 517 (2): 565–86

and there are more citations. Some examples:

1, Search for Supersymmetric Top-Quark Partners Using Support Vector Machines and Upgrade of the Hadron Calorimeter Front-End Readout Control System at CMS by Mehmet Özgür ¸Sahin (2016). “A dark energy permeating the whole space is required to be introduced in order to explain the measurements of the cosmic microwave background [15, 16] and of the type-Ia supernovae at large red-shifts [17, 18], hence the observation of the accelerated expansion of universe.” Where [17] Supernova Search Team Collaboration, A. G. Riess et al., “Observational evidence from supernovae for an accelerating universe and a cosmological constant,” Astron.J. 116 (1998) 1009–1038, arXiv:astro-ph/9805201 [astro-ph]. [18] G. Paal, I. Horvath, and B. Lukacs, “Inflation and compactification from galaxy redshifts?,”.

2, Flavour-tagged Measurement of CP Observables in B0 s K Decays with the LHCb Experiment by Ulrich Paul Eitschberger (2018) “Dark energy on the other hand is an unknown type of energy made responsible for the accelerating expansion of the universe [45, 46].” where [45] G. Paal, I. Horvath, and B. Lukacs, Inflation and compactification from galaxy redshifts?, Astrophys Space Sci 191 (1992) 107. [46] P. J. E. Peebles and B. Ratra, The Cosmological constant and dark energy, Rev. Mod. Phys. 75 (2003) 559, arXiv:astro-ph/0207347 .

4, Cosmolog´ıa de Tiempo Tard´ıo para un Campo Escalar con Acoplamientos Cin´etico y de Gauss-Bonnet by Edwin Loaiza Acu˜na (2016). “El primer artı́culo, que hizo uso de los datos observados para afirmar la existencia de un término lambda positivo fue el de Paál, G. et al. en 1992”

5, Forecasts of two-field inflation by Leung, Godfrey (2015). “Although Λ may contribute to the dark energy (DE) that explains the observed late-time acceleration of our Universe [10]” [10] Paal G., Horvath I., and Lukacs B., “Inflation and compactification from galaxy redshifts?,” Astrophysics and Space Science 191 (1992) 107–124.

6, Modelling Galaxy Evolution in the Era of ALMA and SKA by Danial Yar-Mukhamedov (2015) “Moreover, they have revealed an interesting fact, that the expansion of the Universe is accelerated (Paal et al., 1992).” Katkahosz (talk) 10:02, 3 December 2023 (UTC)

Please link to the articles directly, it makes it much easier to review them.

Doing it manually: The book looks like a crank publication (linked from vixra, which is always a bad sign!). From your first list, #1. published in a potentially predatory journal, not listed in Web of Science (WoS). #2 not listed in WoS. Your second list appears to be entirely passing references, with no particular relevance to the actual text (someone just found some papers discussing dark energy and linked to them). You have provided no evidence of secondary sources taking up Paál's claim of being the first evidence for dark energy. That claim rests on evidence for Redshift quantization, which goes away in larger surveys, hence is plainly incorrect. Beyond that, I'm not sure what to tell you: if you believe Paál's work to be important to the history of dark energy, you'll have to find secondary sources that make that claim. Did you read WP:FRINGE and WP:N, because those are the guiding conventions here? - Parejkoj (talk) 19:47, 3 December 2023 (UTC)

Thanks for your answer. Thank you very much you are discussing this with me. But first we should discuss what we want to discuss.

I do not want to discuss your or my opinions. Because they do not matter. I read WP:FRINGE and WP:N some time ago. I am going to read them carefully once more. I realize they are important.

I tough the facts what matter. Did Paal published these papers? YES! Was it written he calculated Lambda? Yes! Did he use observed data? Yes. Is the value close to the todays accepted one? Yes.

It does not matter what you think or even the other researchers think. It does matter what they write about it. Nobody wrote it is wrong. If nobody wrote it is good, does not matter.

Please, do not talk about Redshift quantization. Paal was the first who suggested it. In that scale it is wrong. But we are not discussing Redshift quantization. Please read the previous discussions in this talk page. Anyway, this also does not matter, as I already wrote nobody's opinion is matter.

I do not want to write the history of dark energy. I do not think Paal's work is important to the history of dark energy. I think this is only a footnote. I do not think Paal was a very important astronomer. But he was the only notable Hungarian cosmologist in the XX. century. So I do think Paal is notable in enwiki. If so, Paal works should be mentioned in his page. This is what I think.

If you think wrong ideas should be deleted from enwiki, start with Ptolemy's and Copernicus', etc. --Katkahosz (talk) 07:47, 4 December 2023 (UTC)

As noted in discussions above, Paál's claim for measuring Lambda rests on his claim for measuring "regularity" (essentially quantized redshifts). That claimed observation is incorrect, hence the model is incorrect, hence the claim for the first measurement of lambda is incorrect. At least one reason there are no papers countering Paál's claim is because as soon as large scale surveys started in the next decade, any such claim for quantized redshifts fell apart completely and it's a waste of time to respond to such claims. - Parejkoj (talk) 17:49, 4 December 2023 (UTC)

OK, I'll give you some more citations, but before that let me answer this. You are discussing, but you are not listening. Have you read what I wrote; Please read the previous discussions in this talk page. Please, do it.

And think about this:

As noted Ptolemy's claim for measuring the movement of planets rests on his claim that the Earth is the center of the world. That claimed observation is incorrect, hence the model is incorrect, hence the claim for the first good calculation of the movement of planets is incorrect.

What do you think? Shall we delete Ptolemy's claim? --Katkahosz (talk) 14:53, 5 December 2023 (UTC)

More citations. Here are other books:

https://www.amazon.com/Viscosity-Hypothesis-Simplest-Possible-Everything/dp/3330087366

https://www.abebooks.com/9783319107370/Weird-Universe-Exploring-Bizarre-Ideas-3319107372/plp

And this article:

https://ui.adsabs.harvard.edu/abs/2019arXiv190711139B/abstract

And once again. Please, do not argue with Paal's model. This is irrelevant. One shall write an article about it and wikipedia should refer it. This talk page is not for scientific discussions. I think. --Katkahosz (talk) 14:59, 5 December 2023 (UTC)

Sorry, what I mean is we can have scientific discussions. But just for fun. Your science opinion or mine is irrelevant what should be on wikipedia pages. --Katkahosz (talk) 15:02, 5 December 2023 (UTC)

So, you've added another fringe pseudoscience cosmology book, a "weird science" book, and a Hungarian summary of his life. None of these are useful secondary sources for determining the notability of Paál's ideas (the latter is probably good to establish his academic notability, for the existence of this page).

You also don't understand my argument: we don't remove discussion of Ptolemy's model (ignoring that it is extremely notable) because the observations underlying it were correct even if the model was wrong. Paál's claimed observation of quasar periodicity is incorrect. The observations drive the models, not the other way round. Much like we don't give Einstein credit as "the first person to suggest a cosmological constant" because he did so for the wrong reason. I don't see much point in continuing this: Wikipedia talk pages are WP:NOTFORUM. - Parejkoj (talk) 17:33, 5 December 2023 (UTC)

Well, I do not categorize books. This is not an argument. OK, some more

https://arxiv.org/abs/gr-qc/0605081

https://ui.adsabs.harvard.edu/abs/2009AIPC.1133..483M/abstract

https://www.aanda.org/articles/aa/full_html/2013/08/aa22088-13/aa22088-13.html

https://www.mdpi.com/2218-1997/1/1/38

https://docplayer.hu/116105196-High-energy-astrophysics-bevezetes-veres-peter-1.html

https://www.epa.oszk.hu/00300/00342/00236/pdf/

And you have not reacted 1-6. previous references. You do not have to answer me, however to finish a conversation, I think both parties should agree with that.

Also, if you ever deduce Einstein's equations from action principle, you would never say that Einstein was not "the first person to suggest a cosmological constant". --Katkahosz (talk) 08:26, 6 December 2023 (UTC)

Sloan Great Wall and Laniakea

In this paper

https://arxiv.org/abs/1907.11139

Balazs (1997–2009 was the director of Konkoly Observatory) wrote a section with the title ‘’Examination of the early years, large-scale inhomogeneities in the Universe’’.

Here is the translation of the section

Examination of the early years, large-scale inhomogeneities in the Universe

By the 50s of the 20th century, there were already many investigations to study the large-scale distribution of matter in the Universe. During this, the frequency of occurrence of galaxies was analyzed in different directions and up to limit luminosities. Of course, the distance of galaxies is related to their apparent luminosity, but the large differences in their absolute luminosity severely limit the statistical efficiency of studies of this nature. On the other hand, clusters formed from galaxies are excellent for studying the large-scale distribution of matter.

In order to examine the spatial distribution, we also need some data related to the distance in the case of sets. Such obvious data are the apparent diameter of the cluster and the brightness of its members. It is a simple mathematical statistical fact that if the absolute luminosity of the galaxies forming the cluster is arranged in order of magnitude, then the 2nd, 3rd, etc. the standard deviation of the brightness of the brightest element is much smaller than that of elements stacked in a row. It is an observational fact that the standard deviation of the absolute brightness of the 10th brightest element in galaxies is only m=0.35 magnitude. The problem, of course, is that clusters are found in much smaller numbers than individual galaxies.

The sky survey carried out in the second half of the 1950s with the Schmidt telescope on Palomar Mountain was the most comprehensive up to that time in terms of sky coverage and cosmic distance depth. Using this survey, Georg O. Abell, an employee of the Mount Wilson Observatory, identified tens of thousands of galaxy clusters and groups. Of these, nearly two thousand were rich enough to be suitable for statistical analysis as a homogeneous sample. The homogeneous sample suitable for further statistical analysis contained 1,682 sets. The survey covered the part of the sky from the North Pole to the -27 declination. This large-scale work also attracted the attention of György Paál, and he subjected the results to a critical examination.

One of the important goals of Abell's galaxy cluster catalog was to verify the validity of cosmological models. Accepting a model, we can determine the distance of an object based on Hubble's law from the value of the redshift measured in its spectrum. The result of course depends on the model used. However, if we can determine the distance in an independent way, then we have a chance to check the validity of the model.

I already mentioned above that the absolute brightness of the 10th brightest element of the cluster can be estimated with an accuracy of m=0.35 magnitude, provided that the absolute brightness distribution within the near and far clusters, the so-called luminosity function is the same for both sets. Of course, this cannot be guaranteed. Abell tried to eliminate this difficulty by introducing the so-called "wealth" classes (wealth class). He classified the clusters according to the number of galaxies that could be identified in them. He set up a total of 5 classes, the "poorest" group included those with 30-79, while the richest included those with more than 300 members.

Cosmological theories posit various relationships between the apparent luminosity, cluster diameter, number of cluster members, and redshift assigned to galaxy clusters. György Paál emphasized that these quantities should only be used to check the given models if they really measure what they refer to, so they are free of systematic errors. He showed that the cluster diameter definition used in the Abell catalog results in a systematic error for distant objects. The consequence of this is that the procedure he used identified a smaller number of sets than the actual number.

György Paál made a suggestion to correct the error. Strangely, the corrected spatial distribution of the fish fit worse to the solutions assuming spatial homogeneity and isotropy obtained from Einstein's equations. From this, he concluded that in the part of space covered by the Abell catalog around our galaxy (it is a sphere with a radius of roughly 700 Mpc), the spatial distribution and/or movement of the clusters does not follow the uniform density and expansion predicted by the models4. He showed that the observed distributions can only be correctly interpreted with the homogeneous isotropic models if we assume a significant positive curvature in the observed part of space, or if the expansion of the Universe slows down at a very rapid rate

Abell's method used to determine the diameter of the clusters was replaced by a new method free of systematic errors. He checked the method personally using the Palomar Atlas owned by the Konkoly Observatory. Starting from the center of the cluster, he counted the galaxies in circles of ever-increasing radius, and then plotted the numerical values thus obtained as a function of the radius of the circles. On the obtained curves, he determined the point where its course deviated the most from the straight line. He accepted the distance of this point from the center as the radius of the set.

The new measurements also confirmed his previously obtained result that within a distance of roughly 400 Mpc from us, the space differs significantly from the Euclidean one, or in this part of the space, the density and/or movement of matter significantly differs from the homogeneous isotropic case. He examined, but dismissed, the possibility that the observed effect was a consequence of the measured redshift not being caused by the Doppler effect due to receding.

The origin and development of inhomogeneities observed in the large-scale distribution of matter

When examining the large-scale inhomogeneities of the cosmic matter, a fundamental question is how well they have preserved the so-called initial conditions. That is, to what extent these conditions can be read from their currently observable state. I have already mentioned above that the large-scale homogeneity and isotropy of the Universe is wide as a result of the revolutionary transformation that took place in cosmology in the 20s and 30s of the last century, has become widely accepted. Following the expansion of the homogeneous isotropic distribution backwards in time, it was naturally assumed that there was an initial very dense primitive state, from which the very rich state in the current structures was created.

Due to the finite propagation speed of light, we see objects at a cosmologically greater distance in their previous state in time. In the case of the most distant objects currently known, the length of this "lookback time" is comparable to the age of the Universe that can be observed with our telescopes. By comparing the structure of objects at different distances, we can trace the formation and development of various cosmic structures (eg. galaxy clusters).

Gravity played the main role in the dismemberment and shaping of the originally "smooth" cosmic matter. The clouds of material that descend as a result of the gravitational disturbance following the densifications/thinnings no longer follow the large-scale general expansion of the cosmic matter, but start an independent life. A fundamental question is whether the gravitational force of the detached cloud is sufficient for this independent life, i.e. is it gravitationally stable? The cloud that has come to life on its own can continue to crumble, and new subsystems can take shape in it. Clusters of galaxies are a characteristic stage of this process.

As part of the revolution in cosmology, the question was raised already in the thirties of the last century, whether the gravitational force acting between the members of the cluster in galaxy clusters is sufficiently large to prevent the cluster from falling apart, i.e. how stable are these formations over time? In 1937, Fritz Zwicky of the California Institute of Technology studied the very rich galaxy cluster in the Coma constellation and concluded in 1937 that the gravitational force of the galaxies that make up the cluster is not sufficient to pull the galaxies that make up the cluster into the observed keep them together against their movement. Given that the cluster appears to be balanced in terms of the distribution of the galaxies in it, there must also be a mass in the cluster whose attraction complements that of the objects visible with our telescopes, and which can only be perceived through its gravitational effect. This is the so-called "dark matter".

The question was raised, how does this only gravitationally detectable material populate the cluster? Reality could be found somewhere between two extremes. At one extreme, dark matter does not stick to galaxies, filling the cluster more or less evenly. The other extreme is that dark matter sticks to galaxies, and most of it sticks to the more massive ones.

After György Paál came to the conclusion by examining Abell's galaxy clusters that their spatial distribution/movement does not follow the rules set by the Cosmological Principle, in the 1970s he investigated in detail the question of what role the presence of dark matter played in the observed discrepancies. He found that after the "Big Bang", when the material of the Universe began to organize itself into structures, some very efficient process must have worked, which formed the currently observable face of the observable galaxy clusters during the available 13 billion years.

He concluded that without the presence of a significant amount of dark matter, the gravitational influence from the light-emitting material objects in the clusters reaching our telescopes is not sufficient to create their current form from the initial state in the time available. The presence of darkness is absolutely necessary for sufficiently rapid development.

The realization of this fact was, in his words, the "rediscovery" of dark matter. He pointed out that the effect of dark matter is extremely sensitive to how it is distributed in the cluster. With specific numerical examples, he proved that if the majority of dark matter adheres to the high-mass galaxies of the cluster, the development rate of the cluster can be up to 3 orders of magnitude faster compared to the state without dark matter.

End translation. Katkahosz (talk) 10:26, 6 December 2023 (UTC)

Is there any notable scientific result here? --Katkahosz (talk) 16:32, 7 December 2023 (UTC)

Doesn't look like it, no. - Parejkoj (talk) 21:36, 7 December 2023 (UTC)

Oh, I am sorry. I forget to mention it, after this sentence

From this, he concluded that in the part of space covered by the Abell catalog around our galaxy (it is a sphere with a radius of roughly 700 Mpc), the spatial distribution and/or movement of the clusters does not follow the uniform density and expansion predicted by the models.

there was a footnote, mentioning that later the Sloan Great Wall and the Laniakea superclusters were discovered. --Katkahosz (talk) 08:36, 8 December 2023 (UTC)

Paal's work about the dark matter is part of the history of dark matter. Since Balazs' work is a secondary sources I am going to include this in some enwiki articles. --Katkahosz (talk) 08:58, 10 December 2023 (UTC)