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== Unclear sentence ==

The intended structure of the following sentence is unclear to me: “Reconciliation of general relativity with the laws of quantum physics remains a problem however, as there is a lack of a self-consistent theory of quantum gravity; and how gravity can be unified with the three non-gravitational forces—strong, weak, and electromagnetic forces.”

A minor issue is that a comma seems necessary before “however.” A more important issue is how the part after the semicolon is related to what comes before. Would the following rewrite be correct? Or would something else be better?

“Reconciliation of general relativity with the laws of quantum physics remains a problem, however, as there is a lack of a self-consistent theory of quantum gravity, and how gravity can be unified with the three non-gravitational forces—strong, weak, and electromagnetic forces—is not yet known.”

] (]) 13:27, 16 June 2022 (UTC)

:Your suggested change would be an improvement. However, I personally would not want to suggest that gravity theory must change to accommodate those other theories. Perhaps they need to change instead. Or perhaps our four-dimensional space-time continuum should be embedded in a higher dimensional space with a more uniform structure, like ]? ] (]) 15:09, 16 June 2022 (UTC)
::Thank you for the reply. I am afraid I don’t understand the issues well enough to feel confident about making any changes to the article (other than adding a comma before "however"). Can you, or someone else, use my suggestion above as a basis for fixing the structure of that sentence? As it is, it doesn’t make sense grammatically. ] (]) 06:38, 18 June 2022 (UTC)
:::To me, the major issue is the forced mashing together of multiple sentences into a single sentence via the semicolon. How about this? “Reconciliation of general relativity with the laws of quantum physics remains a problem, however, as there is a lack of a self-consistent theory of quantum gravity. It not yet known how gravity can be unified with the three non-gravitational forces—strong, weak, and electromagnetic forces.” ] (]) 06:39, 19 June 2022 (UTC)
::::I like this, so I'll 'be bold' and put it in. ] (]) 00:01, 24 June 2022 (UTC)
:::::Many thanks to all of you for your replies and for fixing that sentence! I’ll try to be '''bold'''er next time. ] (]) 12:19, 25 June 2022 (UTC)

== A generalization of the Einstein-Maxwell equations ==

I think the solutions I have obtained will be of interest to the readers of this[REDACTED] article. Since I am the author, I cannot make any related edits. The article has been published open access CC BY 4.0.
Cotton, F.W. A generalization of the Einstein–Maxwell equations. Eur. Phys. J. Plus 136, 162 (2021).
https://doi.org/10.1140/epjp/s13360-021-01115-6 ] (]) 19:32, 30 July 2022 (UTC)


: Thanks for sharing. So far Google Scholar only produces . When this is noticed, picked up and sufficiently cited in the relevant literature, it could be ready for being mentioned in Misplaced Pages. - ] (]) 20:32, 30 July 2022 (UTC)
== Short description ==


== Misplaced Pages is written for narrow experts? ==
{{ping|DVdm}} The original short description contradicts the article. It reads, "Theory by Albert Einstein, covering gravitation in curved spacetime." In reality, general relativity tells us that gravitation manifests itself as the curvature of spacetime. Again, that's not what the article says. My alternative is correct and does not contradict the article. ] (]) 15:42, 22 June 2019 (UTC)
:Then I propose "Theory by Albert Einstein, covering gravitation ''and'' curved spacetime", or better still, "Theory by Albert Einstein, covering gravitation ''as'' curved spacetime". Anyway, my main objection to your proposal was the somewhat accusing tone of the phrase "due to Albert Einstein" {{smiley}}, and the re-splitting of the essential concept of "spacetime" into "space and time". - ] (]) 16:18, 22 June 2019 (UTC)
::I . - ] (]) 08:09, 23 June 2019 (UTC)
:::{{ping|DVdm}} Thank you! That's much better. The word 'as' is the right one here. I think we should also add the adjective 'scientific' to emphasize the fact that general relativity is not a child of an idle mind or some crazy mathematics on a piece of paper but rather a proper scientific theory supported by mountains of empirical evidence. What do you think? ] (]) 02:20, 24 July 2019 (UTC)
:::: I don't think we need that, as the description is already significantly longer than its ]. In order to get closer to 40, perhaps we should amend it to "Einstein's theory of gravitation as curved spacetime".- ] (]) 08:20, 24 July 2019 (UTC)
::::: Fair enough. I think your new proposal is even better. {{smiley}} ] (]) 12:53, 24 July 2019 (UTC)
:::::: {{done}}: . - ] (]) 13:14, 24 July 2019 (UTC)


Misplaced Pages is written for narrow experts? What is the point of placing the forms of writing incomprehensible not to a narrow specialist? For example
== A Commons file used on this page has been nominated for deletion ==
The following Wikimedia Commons file used on this page has been nominated for deletion:
* ]<!-- COMMONSBOT: discussion | 2019-07-13T07:36:39.084409 | Light deflection.png -->
Participate in the deletion discussion at the ]. —] (]) 07:36, 13 July 2019 (UTC)


<math> R_{\mu\nu} - {\textstyle 1 \over 2}R\,g_{\mu\nu} + \Lambda\ g_{\mu\nu} = \frac{8\pi G}{c^{4}}\, T_{\mu\nu} </math>
== refines / supersedes ==


is non-understandable form of writing. Why is the non-understandable form of writing is used unless an understandable form of writing for tensors? But the understandable form of writing is something like this:
To a third party observer like me who watches the page, this seems ridiculous (both are true).<abbr title="Smiling face" style="border-bottom: none;">]</abbr> I suggest to form a consensus here for one or the other instead of constantly switching from one to another... Thanks, —]] – 12:25, 23 July 2019 (UTC)


<math>\mathop {\mu,\nu}\limits_{ \ge 0}^{n \le } \left\{ {R_{\mu\nu} - {\textstyle 1 \over 2}R\,g_{\mu\nu} + \Lambda\ g_{\mu\nu} = \frac{8\pi G}{c^{4}}\, T_{\mu\nu}} \right. </math>
Well, or for an alternative that conveys more clearly the intended meaning, of course. —]] – 12:25, 23 July 2019 (UTC)


or
: Agreed. My take on it: as Newton's theory is still perfectly valid and useful in the low-gravity-low-speed limit, I think that "refines" is better (—even if perhaps just slightly—) than "supersedes". I don't think we need to worry about how flat-earthers (, , ) might get confused by either alternative here. - ] (]) 13:11, 23 July 2019 (UTC)


<math> \mathop \mu\limits_{ \ge 0}^{n \le } \left\{ {\mathop \nu\limits_{ \ge 0}^{n \le } \left\{ R_{\mu\nu} - {\textstyle 1 \over 2}R\,g_{\mu\nu} + \Lambda\ g_{\mu\nu} = \frac{8\pi G}{c^{4}}\, T_{\mu\nu} \right.} \right. </math>
::Likewise. There is no need to pay attention to the people who believe the Earth is flat. Such an idea is untenable even by the standards of 2000 years ago. ] (]) 02:16, 24 July 2019 (UTC)


or
== A Commons file used on this page or its Wikidata item has been nominated for deletion ==
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion:
* ]<!-- COMMONSBOT: discussion | 2020-02-09T23:37:02.985403 | Relativistic precession.svg -->
Participate in the deletion discussion at the ]. —] (]) 23:37, 9 February 2020 (UTC)


<math> \mathop {\left\{ {} \right.}\limits_{\mu = 0}^n \mathop {\left\{ {} \right.}\limits_{\nu = 0}^n R_{\mu\nu} - {\textstyle 1 \over 2}R\,g_{\mu\nu} + \Lambda\ g_{\mu\nu} = \frac{8\pi G}{c^{4}}\, T_{\mu\nu} </math>
== Books ==


These forms of writing clearly indicate the system of equations and quantity of this equations. At the same time, this form is the same short. Unfortunately, it is difficult to find literature that would prove the importance of using such forms for better understanding by readers. At the same time, I do not understand why this problem is not obvious for writers. ] (]) 08:18, 28 February 2023 (UTC)
Shall we create a separate page for the notable books on general relativity at various levels? This article is already long in its current state. We do have pages for lists of ], of ], and ]. ] (]) 00:37, 14 June 2020 (UTC)


== Poincare ==
== 4D Spacetime: 3D Regular Space + Time ==
Lorentz thought that gravity was electromagnetic, but not Poincare. Poincare did have a relativistic gravity theory. See <ref>{{ cite web |title=Walter, Breaking in the 4-vectors |url=http://scottwalter.free.fr/papers/2007-genesis-walter.html}}</ref><ref>{{ cite web |title=Walter, Breaking in the 4-vectors |url=https://link.springer.com/chapter/10.1007/978-1-4020-4000-9_18}}</ref>. So I do not think the last edit is correct. ] (]) 05:15, 24 July 2023 (UTC)


: Weinstein translates a crucial passage from his 1905 note (which he expanded to a full paper in 1906) as follows: "If we were to admit the postulate of relativity, we would find the same number in the law of gravitation and the laws of electromagnetism – the speed of light – and we would find it again in all other forces of any origin whatsoever. This state of affairs may be explained in one of two ways: either everything in the universe would be of electromagnetic origin, or this aspect – shared, as it were, by all physical phenomena – would be a mere epiphenomenon, something due to our methods of measurement".<ref name="Weinstein">{{cite web |last1=Weinstein |first1=Galina |title=Poincaré's Dynamics of the Electron – A Theory of Relativity? |url=https://arxiv.org/ftp/arxiv/papers/1204/1204.6576.pdf |website=arXiv.org |publisher=Cornell University |access-date=24 July 2023}}</ref>
Einstein recognized the '''4 dimensions of spacetime: 3D regular space + time'''. ] (]) 13:01, 21 August 2020 (UTC)
: In other words, Poincare expressed a faith that either (1) gravitation would ultimately prove to be of electromagnetic origin, or (2) both gravitation and electromagnetism would be "epiphenomena" of some deeper theory.
: In both 1905 note and his 1906 article, Poincare argued against an infinite speed of gravitation as representing a violation of the principle of relativity, which he considered absolute. Asserting that gravitational forces must obey the principle of relativity is, in my opinion, a far cry from being able to state that Poincare had anything resembling a relativistic theory of gravity. However, it would be correct to state that Poincare derived some results in what would today be called "relativistic gravitation".<ref name="Damour">{{cite web |last1=Damour |first1=Thibault |title=Poincaré, the Dynamics of the Electron, and Relativity |url=https://arxiv.org/pdf/1710.00706.pdf |website=arXiv.org |publisher=Cornell University |access-date=24 July 2023}}</ref> ] (]) 08:20, 24 July 2023 (UTC)
:: I guess you are agreeing that it is incorrect to say option (1) is Poincare's belief. He is favoring option (2). Option (2) does not say that gravitation and electromagnetism are from a deeper theory. It says that "this aspect" (propagating at the speed of light) is "due to our methods of measurement". That option is not much different from what many say today.
:: Weinstein says "when discussing his theory of gravitation, Poincaré extended his mathematical theory of groups from electrodynamics to gravitation." Damour says "Poincare’s June 5, 1905 Note announces important mathematical and physical advances in what we would call today, Special Relativity, relativistic electrodynamics and relativistic gravitation". Walter says "In July, 1905, Henri Poincaré (1854–1912) proposed two laws of gravitational attraction compatible with the principle of relativity and all astronomical observations explained by Newton’s law." So I think it is fair to say Poincare proposed a relativistic theory of gravity. ] (]) 17:22, 24 July 2023 (UTC)
::: I would no more state that than I would agree that Einstein proposed a relativistic theory of gravity in 1907 because, using relativistic arguments, he predicted gravitational time dilation and, in 1911, the bending of light. Einstein made a few predictions, but he had not yet tied everything together in a coherent theory. Neither did Poincare. ] (]) 20:54, 24 July 2023 (UTC)
:::: Your edit is still wrong. You say Poincare made an "assumption that gravitation should ultimately have a common origin with electromagnetism". That is not true. Poincare said that Lorentz made such an assumption, and Poincare was pointedly not making that assumption. Then you say that he made a prediction as a consequence of that assumption. None of the primary or secondary sources say that. On the contrary, Poincare said that it was a consequence of his relativity theory that nothing goes faster than the speed of light. Before Poincare, it was thought that gravity went faster. ] (]) 01:59, 25 July 2023 (UTC)
{{reflist-talk}}


== Problems with Einstein's general theory of relativity ==
== Possible incorrect equation? ==


The article " ] " was online for about eight or so weeks but then failed to survive a vfd.
Under "Total force in general relativity":


If anyone's looking for the content, it's now online again, at http://dx.doi.org/10.13140/RG.2.2.16665.12649
Applying <math>F(r) = - \frac{\partial U}{\partial r}</math> to the given formula for potential energy gives <math>\frac{GMm}{r^2} - \frac{L^2}{mr^3} + \frac{3GML^2}{mc^2 r^4}</math>. Is the force equation currently in the article incorrect?
TeX seems reluctant to parse minus signs... <!-- Template:Unsigned --><span class="autosigned" style="font-size:85%;">—&nbsp;Preceding ] comment added by ] (] • ]) 12:57, 14 January 2021 (UTC)</span> <!--Autosigned by SineBot-->


This seems to be the best listing of its type available. The problems highlighted are specific to the consequences of Einstein's 1913-1916 ''attempt to construct'' a general theory, starting from an SR foundation (an approach that he later rejected, in 1950) ... that is, they are not obviously issues with ''the fundamental concept'' of a general theory, only with Einstein's flawed ''attempted implementation''. You're welcome. ] (]) 20:43, 18 January 2025 (UTC)
:<small>Please ] all your talk page messages with four tildes (<nowiki>~~~~</nowiki>) — See ]. Thanks.</small>
:{{rto|Compoteleon}} There currently is a problem with rendering minus signs in Chrome and Edge. Firefox is doing fine. See ] - ] (]) 14:45, 14 January 2021 (UTC)

Latest revision as of 18:23, 19 January 2025

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Unclear sentence

The intended structure of the following sentence is unclear to me: “Reconciliation of general relativity with the laws of quantum physics remains a problem however, as there is a lack of a self-consistent theory of quantum gravity; and how gravity can be unified with the three non-gravitational forces—strong, weak, and electromagnetic forces.”

A minor issue is that a comma seems necessary before “however.” A more important issue is how the part after the semicolon is related to what comes before. Would the following rewrite be correct? Or would something else be better?

“Reconciliation of general relativity with the laws of quantum physics remains a problem, however, as there is a lack of a self-consistent theory of quantum gravity, and how gravity can be unified with the three non-gravitational forces—strong, weak, and electromagnetic forces—is not yet known.”

Tom Gally (talk) 13:27, 16 June 2022 (UTC)

Your suggested change would be an improvement. However, I personally would not want to suggest that gravity theory must change to accommodate those other theories. Perhaps they need to change instead. Or perhaps our four-dimensional space-time continuum should be embedded in a higher dimensional space with a more uniform structure, like Minkowski space? JRSpriggs (talk) 15:09, 16 June 2022 (UTC)
Thank you for the reply. I am afraid I don’t understand the issues well enough to feel confident about making any changes to the article (other than adding a comma before "however"). Can you, or someone else, use my suggestion above as a basis for fixing the structure of that sentence? As it is, it doesn’t make sense grammatically. Tom Gally (talk) 06:38, 18 June 2022 (UTC)
To me, the major issue is the forced mashing together of multiple sentences into a single sentence via the semicolon. How about this? “Reconciliation of general relativity with the laws of quantum physics remains a problem, however, as there is a lack of a self-consistent theory of quantum gravity. It not yet known how gravity can be unified with the three non-gravitational forces—strong, weak, and electromagnetic forces.” Prokaryotic Caspase Homolog (talk) 06:39, 19 June 2022 (UTC)
I like this, so I'll 'be bold' and put it in. David Spector (talk) 00:01, 24 June 2022 (UTC)
Many thanks to all of you for your replies and for fixing that sentence! I’ll try to be bolder next time. Tom Gally (talk) 12:19, 25 June 2022 (UTC)

A generalization of the Einstein-Maxwell equations

I think the solutions I have obtained will be of interest to the readers of this[REDACTED] article. Since I am the author, I cannot make any related edits. The article has been published open access CC BY 4.0. Cotton, F.W. A generalization of the Einstein–Maxwell equations. Eur. Phys. J. Plus 136, 162 (2021).

     https://doi.org/10.1140/epjp/s13360-021-01115-6 71.183.235.5 (talk) 19:32, 30 July 2022 (UTC)
Thanks for sharing. So far Google Scholar only produces this. When this is noticed, picked up and sufficiently cited in the relevant literature, it could be ready for being mentioned in Misplaced Pages. - DVdm (talk) 20:32, 30 July 2022 (UTC)

Misplaced Pages is written for narrow experts?

Misplaced Pages is written for narrow experts? What is the point of placing the forms of writing incomprehensible not to a narrow specialist? For example

R μ ν 1 2 R g μ ν + Λ   g μ ν = 8 π G c 4 T μ ν {\displaystyle R_{\mu \nu }-{\textstyle 1 \over 2}R\,g_{\mu \nu }+\Lambda \ g_{\mu \nu }={\frac {8\pi G}{c^{4}}}\,T_{\mu \nu }}

is non-understandable form of writing. Why is the non-understandable form of writing is used unless an understandable form of writing for tensors? But the understandable form of writing is something like this:

μ , ν 0 n { R μ ν 1 2 R g μ ν + Λ   g μ ν = 8 π G c 4 T μ ν {\displaystyle \mathop {\mu ,\nu } \limits _{\geq 0}^{n\leq }\left\{{R_{\mu \nu }-{\textstyle 1 \over 2}R\,g_{\mu \nu }+\Lambda \ g_{\mu \nu }={\frac {8\pi G}{c^{4}}}\,T_{\mu \nu }}\right.}

or

μ 0 n { ν 0 n { R μ ν 1 2 R g μ ν + Λ   g μ ν = 8 π G c 4 T μ ν {\displaystyle \mathop {\mu } \limits _{\geq 0}^{n\leq }\left\{{\mathop {\nu } \limits _{\geq 0}^{n\leq }\left\{R_{\mu \nu }-{\textstyle 1 \over 2}R\,g_{\mu \nu }+\Lambda \ g_{\mu \nu }={\frac {8\pi G}{c^{4}}}\,T_{\mu \nu }\right.}\right.}

or

{ μ = 0 n { ν = 0 n R μ ν 1 2 R g μ ν + Λ   g μ ν = 8 π G c 4 T μ ν {\displaystyle \mathop {\left\{{}\right.} \limits _{\mu =0}^{n}\mathop {\left\{{}\right.} \limits _{\nu =0}^{n}R_{\mu \nu }-{\textstyle 1 \over 2}R\,g_{\mu \nu }+\Lambda \ g_{\mu \nu }={\frac {8\pi G}{c^{4}}}\,T_{\mu \nu }}

These forms of writing clearly indicate the system of equations and quantity of this equations. At the same time, this form is the same short. Unfortunately, it is difficult to find literature that would prove the importance of using such forms for better understanding by readers. At the same time, I do not understand why this problem is not obvious for writers. Voproshatel (talk) 08:18, 28 February 2023 (UTC)

Poincare

Lorentz thought that gravity was electromagnetic, but not Poincare. Poincare did have a relativistic gravity theory. See . So I do not think the last edit is correct. Roger (talk) 05:15, 24 July 2023 (UTC)

Weinstein translates a crucial passage from his 1905 note (which he expanded to a full paper in 1906) as follows: "If we were to admit the postulate of relativity, we would find the same number in the law of gravitation and the laws of electromagnetism – the speed of light – and we would find it again in all other forces of any origin whatsoever. This state of affairs may be explained in one of two ways: either everything in the universe would be of electromagnetic origin, or this aspect – shared, as it were, by all physical phenomena – would be a mere epiphenomenon, something due to our methods of measurement".
In other words, Poincare expressed a faith that either (1) gravitation would ultimately prove to be of electromagnetic origin, or (2) both gravitation and electromagnetism would be "epiphenomena" of some deeper theory.
In both 1905 note and his 1906 article, Poincare argued against an infinite speed of gravitation as representing a violation of the principle of relativity, which he considered absolute. Asserting that gravitational forces must obey the principle of relativity is, in my opinion, a far cry from being able to state that Poincare had anything resembling a relativistic theory of gravity. However, it would be correct to state that Poincare derived some results in what would today be called "relativistic gravitation". Prokaryotic Caspase Homolog (talk) 08:20, 24 July 2023 (UTC)
I guess you are agreeing that it is incorrect to say option (1) is Poincare's belief. He is favoring option (2). Option (2) does not say that gravitation and electromagnetism are from a deeper theory. It says that "this aspect" (propagating at the speed of light) is "due to our methods of measurement". That option is not much different from what many say today.
Weinstein says "when discussing his theory of gravitation, Poincaré extended his mathematical theory of groups from electrodynamics to gravitation." Damour says "Poincare’s June 5, 1905 Note announces important mathematical and physical advances in what we would call today, Special Relativity, relativistic electrodynamics and relativistic gravitation". Walter says "In July, 1905, Henri Poincaré (1854–1912) proposed two laws of gravitational attraction compatible with the principle of relativity and all astronomical observations explained by Newton’s law." So I think it is fair to say Poincare proposed a relativistic theory of gravity. Roger (talk) 17:22, 24 July 2023 (UTC)
I would no more state that than I would agree that Einstein proposed a relativistic theory of gravity in 1907 because, using relativistic arguments, he predicted gravitational time dilation and, in 1911, the bending of light. Einstein made a few predictions, but he had not yet tied everything together in a coherent theory. Neither did Poincare. Prokaryotic Caspase Homolog (talk) 20:54, 24 July 2023 (UTC)
Your edit is still wrong. You say Poincare made an "assumption that gravitation should ultimately have a common origin with electromagnetism". That is not true. Poincare said that Lorentz made such an assumption, and Poincare was pointedly not making that assumption. Then you say that he made a prediction as a consequence of that assumption. None of the primary or secondary sources say that. On the contrary, Poincare said that it was a consequence of his relativity theory that nothing goes faster than the speed of light. Before Poincare, it was thought that gravity went faster. Roger (talk) 01:59, 25 July 2023 (UTC)

References

  1. "Walter, Breaking in the 4-vectors".
  2. "Walter, Breaking in the 4-vectors".
  3. Weinstein, Galina. "Poincaré's Dynamics of the Electron – A Theory of Relativity?" (PDF). arXiv.org. Cornell University. Retrieved 24 July 2023.
  4. Damour, Thibault. "Poincaré, the Dynamics of the Electron, and Relativity" (PDF). arXiv.org. Cornell University. Retrieved 24 July 2023.

Problems with Einstein's general theory of relativity

The article " Problems with Einstein's general theory of relativity " was online for about eight or so weeks but then failed to survive a vfd.

If anyone's looking for the content, it's now online again, at http://dx.doi.org/10.13140/RG.2.2.16665.12649

This seems to be the best listing of its type available. The problems highlighted are specific to the consequences of Einstein's 1913-1916 attempt to construct a general theory, starting from an SR foundation (an approach that he later rejected, in 1950) ... that is, they are not obviously issues with the fundamental concept of a general theory, only with Einstein's flawed attempted implementation. You're welcome. ErkDemon (talk) 20:43, 18 January 2025 (UTC)

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