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Discussion of BGV theorem does not belong in lede

I removed the following material from the lede. I suggest that a more appropriate location for discussion of the BGV theorem would be in the articles on Cosmology or on the Big Bang. Could somebody with more expertise on these subjects check whether incorporation of this material into those articles is appropriate? Thanks!

The BGV theorem demonstrates that classical spacetime, under a single, extremely general state, cannot be prolonged to past infinity but must arrive at a boundary at some moment in the finite past.

Prokaryotic Caspase Homolog (talk) 13:27, 28 May 2021 (UTC)

References

Addition to History of Special Relativity

time cannot be separated from the three dimensions of space except for wave particles with a velocity equal to the speed of light

Einstein's Original Paper on Special Relativity https://www.fourmilab.ch/etexts/einstein/specrel/specrel.pdf Page 22 "Thus, when v = c, W becomes infinite"

In the context of special relativity, time cannot be separated from the three dimensions of space except for wave particles with a velocity equal to the speed of light, because the observed rate at which time passes for an object depends on the object's velocity relative to the observer. General relativity also provides an explanation of how gravitational fields can slow the passage of time for an object as seen by an observer outside the field. — Preceding unsigned comment added by AtlasDidntShrug (talk • contribs) 17:29, 11 February 2022 (UTC)

Please put new talk page messages at the bottom of talk pages and sign your messages with four tildes (~~~~) — See Help:Using talk pages. Thanks.

@AtlasDidntShrug: The cited source (Einstein's 1905 article) does not mention wave–particle duality, so we cannot use that for such content. See, for instance, wp:original research and wp:synth. DVdm (talk) 18:40, 11 February 2022 (UTC)

Existing articles on (Introduction to the) mathematics of general relativity are virtually useless

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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My recent DIFF addition to the Spacetime article was reverted by User:Zefr, justified by policies WP:SYNTH and WP:NOTTEXTBOOK.

I created this new section because, quite frankly, I find the existing articles on Introduction to the mathematics of general relativity and Mathematics of general relativity to be virtually useless for their presumably intended target audiences. These two articles are nothing but lists of mathematical concepts that provide the reader with virtually no clues as to how these concepts apply to general relativity.

The existing two Wikipedia articles on this subject provide absolutely no assistance to, say, a college student who wants a bit of guidance getting through a chapter of, say, Hartle, Wald, or Schultz.

• In regards to WP:SYNTH: I have, as much as possible, tried to avoid introducing my own original thoughts on the subject. Unfortunately, adding ALL of the citations that I could have put in to justify each and every single statement to show that I haven't been trying to show off my own thoughts on the subject would have made the text unreadable. I chose to limit my citations to the more obvious.
• In regards to WP:NOTTEXTBOOK: If, by this objection, User:Zefr means that I have provided many detailed derivations, I assert that the presence of detailed derivations does not make an article a textbook. I note that derivations are common in articles on relativistic topics. For example:
  • Relativistic_Doppler_effect#Relativistic_longitudinal_Doppler_effect
  • Michelson–Morley_experiment#Light_path_analysis_and_consequences
  • Kennedy–Thorndike_experiment#Basic_theory_of_the_experiment
  • Special_relativity#Invariant_interval
  • and so on and so forth...

The only thing that I have done here that is different from the above, is that I have strung together a series of related derivations together in logical, coherent order, following as guide a classic semi-popular book on the subject by Lillian Lieber, whom many of you might recognize as the author of The Education of T.C. Mits.

• Do we want Wikipedia to be a useful resource?
• Or do we insist that Wikipedia adhere rigidly to general guidelines that result in the articles becoming useless for their supposedly intended purpose?

Prokaryotic Caspase Homolog (talk) 17:59, 27 March 2022 (UTC)

Understanding derivations, rather than merely knowing abstract definitions, is an important part of physics and mathematics. I note that many mathematical articles, especially those of an introductory nature (directed towards K-12 students), include derivations as an integral part of their presentation. Articles covering upper-level topics tend to be more abstract. Here are some examples of mathematics articles that use derivations, interpretative segments, "how to" segments, and detailed discussion of specific use cases as part of their presentation.

• Quadratic equation
• Solving quadratic equations with continued fractions
• Linear equation
• Cubic function
• and so forth

Prokaryotic Caspase Homolog (talk) 08:11, 30 March 2022 (UTC)

Notes

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

What constitutes "encyclopedic content"?

@Zefr and Roxy the dog: I wish you two guys had responded to my original Talk page post above rather than ignoring it and then arbitrarily reverting after I had tried to follow the wp:BOLD, revert, discuss cycle.

Zefr: You justify your second revert stating that Wikipedia needs to provide summarized content from WP:SCIRS reviews. Of my six most cited sources:

• Of the original 1945 edition of Lieber, Einstein wrote: "A clear and vivid exposition of the essential ideas and methods of the theory of relativity...warmly recommended especially to whose who cannot spend too much time on the subject." Water Isaacson wrote: "This is the clearest explanation of relativity available — and the most fun. It's great to have it available again."
• D'Inverno (1992) is the first edition of standard textbook. I am eagerly awaiting the second edition which will be out soon.
• Adler (2021) is a standard textbook
• Grøn (2011) is a standard textbook
• Lawden (2002) is a Dover reprint of a formerly standard text
• Kay (2011) is a Schaums Outline Series review.

I would like to know which of these above sources fails WP:SCIRS?

Roxy the dog: What is "encyclopedic"? Is it an article like Introduction to the mathematics of general relativity which follows the forms of an encyclopedia article, but which, as I noted in my previous Talk page post, cannot realistically be used as a resource by anybody studying general relativity who wants help understanding a concept? I looked at that article and I didn't see how I could possibly rewrite it into anything useful. Prokaryotic Caspase Homolog (talk) 21:51, 10 April 2022 (UTC)

That's an interesting question, to which I reply, not totally jokingly, will anybody studying general relativty be consulting wikipedia? This also begs the same question regarding this article? Would what you wrote be at all helpful to 95% of people seeking to understand spacetime by looking here? Most of us are not keyboard players. -Roxy the grumpy dog. wooF 22:32, 10 April 2022 (UTC)

Why do people consult Wikipedia?

Wikipedia:Academic use says "...Wikipedia is increasingly used by people in the academic community, from first-year students to distinguished professors, as an easily accessible tertiary source for information about anything and everything and as a quick "ready reference", to get a sense of a concept or idea. [Discussion follows about Wikipedia not being a reliable source...]"

https://diff.wikimedia.org/2018/03/15/why-the-world-reads-wikipedia/ says "From these graphs, we see that on average around 35 percent of Wikipedia users across these languages come to Wikipedia for looking up a specific fact, 33 percent come for an overview or summary of a topic, and 32 percent come to Wikipedia to read about a topic in-depth."

In other words, people people consult Wikipedia for many reasons, and Wikipedia articles are written starting with a wide variety of assumptions about their potential readership. Good articles are written in a layered fashion so as to be accessible to the widest possible readership, starting with a general overview in the lede, then going deeper.

I wrote my section for the "32 percent [who] come to Wikipedia to read about a topic in-depth" but whose mathematics background is limited to, say, about a year of calculus. My proposed section is no good for people wanting to look up a specific fact, and it is no good for people wanting a simple overview of the topic. For that, the first five sections of the article suffice.

It seems to me that you and user:Zefr believe that only the first two audiences (people looking up a specific fact, and people wanting an overview of a topic) should be served by Wikipedia. Articles (and sections of articles) attempting in-depth coverage are, in your opinions, "non-encyclopedic". Is that a correct characterization, or am I distorting your viewpoints?

Prokaryotic Caspase Homolog (talk) 05:13, 11 April 2022 (UTC)

"Encyclopedic content" can be interpreted from several topics under WP:NOT: it is 1) not a dictionary for math derivations about spacetime; 2) not a math essay, forum, manual, or repository of calculations to interpret spacetime; 3) not a math journal or textbook, which states the "purpose of Wikipedia is to summarize accepted knowledge, not to teach subject matter" about math background for spacetime; and 4) WP:NOTEVERYTHING: "Information should not be included in this encyclopedia solely because it is true or useful. A Wikipedia article should not be a complete exposition of all possible details." These examples are the background for my reverts and edit summaries. An encyclopedia is to inform generally – which the article provided before such extensive math solutions were offered – not instruct in calculus unfamiliar to general users. There has been no show of support for your section by other editors. Your work may be better placed in the The Wikijournal of Science math section. Zefr (talk) 16:35, 11 April 2022 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for deletion

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Participate in the deletion discussion at the nomination page. —Community Tech bot (talk) 01:53, 10 November 2022 (UTC)