Talk:Chronology of the universe

Outline of Chronology at Odds with Cosmological Standard Model

The image im Chronology shows Inflation which - while it does explain the fine adjustment problem underlying the flatness of space - is by its nature of taking place before recombinant an unfalsifiable hypothesis and is not part of the standard model. PixelRayn (talk) 11:52, 30 June 2022 (UTC)

The article, nor the image you mention, does not claim to represent only the Lambda-CDM model, which is not at odds with and can accommodate inflation. As for its falsifiability, some cosmologists (like Roger Penrose) would argue that it very well is falsifiable and may have already been falsified. But until some general consensus among cosmologists is reached, and as inflation is currently a popular explanation for big bang cosmology, I don't see any issues with including it in this article. Especially since the article does mention its standing, or lack thereof, in the various big bang stages. elentir (talk) 12:36, 30 June 2022 (UTC)

Detecting photons from 13.2+ billion light years away.

For the Hubble and Webb telescopes to be able to detect radiation from over 13 billion light years away then the dark or ordinary matter that our galaxy is made from must have already existed at or near that distance from the origin of the universe when those early galaxies started forming.

If this is not the case then the universe must have expanded about 13 billion times faster than light else that radiation would already have passed us billions of years ago never to be detectable again. 

What am I missing in my understanding? 86.15.61.16 (talk) 16:08, 13 July 2022 (UTC)

The universe is expanding, which means that we're not seeing further out but rather the space between us is increasing. The expansion is happening in all directions, so the origin (or centre) of the universe is not one specific point in space, but everywhere in space. See: Expansion of the universe, Hubble's law. Lightbloom (talk) 19:39, 8 September 2023 (UTC)

Emergence of nucleons may have been earlier than stated

The following:

"At about one second, neutrinos decouple; these neutrinos form the cosmic neutrino background (CνB). If primordial black holes exist, they are also formed at about one second of cosmic time. Composite subatomic particles emerge—including protons and neutrons—and from about 2 minutes, conditions are suitable for nucleosynthesis"

This implies the first emergence of nucleons was after one second.

Later, the Tabular Summary says that hadronisation will occur at 1e-5 seconds and 150 MeV. This is much earlier than one second; the 150 MeV value is consistent with the article "Color Confinement" which states the Hagedorn temperature corresponds to 130 to 140 MeV.

Spope3 (talk) 05:11, 15 September 2022 (UTC)

Article issues and classification

It is practically impossible to tell what is original research and what is not. There are unsourced sentences, paragraphs, and subsections. The article has "citation needed" tags from April 2018, September 2018, September 2020, and January 2023. There is also a March 2021 "section needs additional citations" tag.

The B-class criteria #1 states; The article is suitably referenced, with inline citations. It has reliable sources, and any important or controversial material which is likely to be challenged is cited. According to this the article does not meet the criteria.

There are thirteen entries in the "External links". Three seems to be a normally acceptable number and of course, everyone has their favorite to add for four. The problem is that none is needed for article promotion.

For the sake of completeness and perspective, I recommend that the Tabular Summary be expanded by one column to show the radius of the universe at each state/time period described, rather than simply and unsystematically throwing size/radius information into the general descriptions.

• ELpoints #3) states: Links in the "External links" section should be kept to a minimum. A lack of external links or a small number of external links is not a reason to add external links.
• LINKFARM states: There is nothing wrong with adding one or more useful content-relevant links to the external links section of an article; however, excessive lists can dwarf articles and detract from the purpose of Wikipedia. On articles about topics with many fansites, for example, including a link to one major fansite may be appropriate.
• WP:ELMIN: Minimize the number of links. -- Otr500 (talk) 16:57, 27 February 2023 (UTC)

Nominate Bad References For Removal

I'd argued for cleanup of the references/external links.

The topic itself is highly based in theoretical research and data analysis. While many things like the Standard Model are the 'currently accepted' model; other areas are more tenuous in what is 'generally accepted, based on available evidence/data', and in the case of pre-Lambda CDM, fundamentally 'theory' at best...since nothing can be directly observed, only theorized based on experiments (IE in particle accelerators).

Point
For such a topic, IMO the level of scrutiny of what is a reputable source should be higher. References like powerpoints (from lectures, w/o any works cited, or affiliated papers), obsolete papers, webpages (w/o immediate works cited/links to sources) should be removed. For topics that aren't entrenched in theoretical sciences 'sure' a reference like above may meet threshold of acceptability, but it would seem logical that when the topic (say very early universe) involves science disciplines where anything reputable (in that field) is backed up by peer-reviewed papers, only references backed by such things should be used.

Examples (I nominate for removal)

• 37. Hawking's paper is from '71 and many findings since then make much of that content obsolete or, at best, partially relevant; making this either a misleading or dissonant reference.
• 38. Kuffmann. This is a lecture, and while the Max Plank Institutes are highly respected in field of physics and astronomy; it doesn't provide anything beyond the powerpoint: no papers, links to research, its just a powerpoint of generalized statements. Not good source for the topic, even as a secondary/tertiary reference.
• 42. Ryder's "Astronomy 162 - Lecture 44" is same, but worse: not even the lecture or powerpoint, but 'notes'. Notes aren't always written by the Professors themselves, and many are written by aides, teaching assistants, etc. Is 'reputability' purely based on fact it was 'a professor' at 'a university'?
• 55. Amos, Jonathan. This is an article from BBC News. The source is more 'sensational' then scientific; and befits current events or politics. etc. While it references a couple papers or ongoing experiments; the article itself appears bombastic and doesn't go into anything (of any actual detail) related to the 21cm radiation, or events in early universe. ultimately no content worth referencing, that hasn't been referenced by more reputable sources than a media outlet
• 78. Landau's article about the 'most distant galaxy observed'. This is from 2013 and obsolete since launch of JWST, and many high-redshifted galaxies its looking at are far more distant. The galaxy she references is z8 GND5296 (RS of 7.5x), whereas current (Nov 2024) has JADES GS z14-0 and z14-1 (RS of 14.32 and 13.90 respectively). NOTE: The entire 'Galaxies, clusters, Superclusters' section needs rewriting. Much of wording in these 3 paragraphs is obsolete, even before JWST's observations in 2020s: much of it is from 2000s or early 2010s.
• 81. Drake, Nadia. Regarding 'most distant galaxy observed'. Its obsolete. GN-z11 isn't in the top5 as of Nov 2024
• 86. Siegel, Ethan. this is a forbes article. Forbes doesn't specialize in astrophysic, astronomy, cosmogony content. This is more 'sensational' then it is meaningful and doesn't provide supportive evidence.
  It in fact contradicts one of the prevailing (current) theories for far-distant future of the universe, specifically regarding the 'Black Hole Era'. Currently while 'finer' points of this era are up for debate, generally it would consist of Quantum-Tunneling turning iron stars to black hole (which evaporate via hawking radiation to subatomic particles). Take the following from the article which goes against both current theories, and more generally, the basic math involved in calculating decay:

  "You might think that after googols and googols of years, anything still present in a galaxy will eventually be consumed, but don't forget about Hawking radiation: eventually, all the Universe's black holes will decay, too. Before any substantial fraction of the remaining galactic matter — normal or dark — can be devoured, every black hole in the Universe will have completely decayed away.

  This article's content doesn't fit into a Big Rip, Big Crunch, nor Heat Death 'end of universe' scenarios. When they state "After 10^26 years have gone by, for example, the Earth will inspiral into (what's left of) the Sun"...No reputability or meaningful information worth referencing.

A Good Example In contrast 57. (Link to Richard Ellis' university homepage).
This more reputable than the above. It provides links to what is being stated on the homepage, links to his peer-reviewed publications. I'd argue that this be a good benchmark for references like personal (university) webpages, lecture powerpoints, lecture notes. etc.

I'm newer to this, so wanted to bring this up here. I'll let somebody more experienced make the necessary changes after any consensus on this is reached. 72.131.34.32 (talk) 00:52, 19 November 2024 (UTC)

First thanks for posting!

I would like to make some practical suggestions: register for an account since IP addresses change and edits from IP addresses are immediately suspect because so many are vandals. Start small, it's hard to discuss a long list in these pages. Read about the importance of secondary sources. Don't use the ref number since these change often.

Overall I agree with your goals up to a point. Better references are really important. However, this is an encyclopedia and not a news site or database. So verifiable secondary references are the goal, even at the expressed expense of being up to date.

I don't agree with some of the detail in your critique.

• Hawking 1971: the primary reference but one cited over 2000 times. Considered reliable unless a review expressly explains why it is not.
• Kuffmann. This is a lecture: Guinevere Kauffmann is Scientific Director, Max Planck Institute for Astrophysics and coauthor on many highly cited papers. See WP:SPS "Self-published expert sources may be considered reliable when produced by an established subject-matter expert, whose work in the relevant field has previously been published by reliable, independent publications".
• Ryden is not in the same league as Kuffman but the real issue is that the content connected to the ref is incorrect.
• Amos, Jonathan. This is an article from BBC News. In my opinion the science writing at BBC is decent and there is editorial oversight. The real issue is that the article is about a preprint and should be excluded on that ground. In the meantime the article was published and has more than 1000 citations. Look for a review article that refs the article. If the BBC is consistent with the review, give both refs. We don't need to remove refs just because the org they come from also publishes news.
• Landau. Same issues
• Nadia Drake. Most distant galaxy. I would simply delete that sentence as off-topic. Any "most" claims in astronomy are wrong and pointless. The claim needs to have some connection to chronology to belong here.
• Siegel, Ethan. this is a forbes article: Forbes does not specialize in astrophysics but Ethan Siegel does and he has a solid reputation. His page does have some supportive evidence.

By comparison to other sources I see, these are not horrible. There are good textbooks and review articles for most of these points and replacing these kinds of refs with better ones would be great. Too many pages have large amounts of content with no refs: if you doubt the content, delete it. Incorrect summaries of sources is surprisingly common: when in doubt verify.

Hope this helps. Johnjbarton (talk) 01:48, 19 November 2024 (UTC)