Undid revision 1101427685 by JayBeeEll (talk) no. Tags: Undo Reverted |
XOR'easter (talk | contribs) Undid revision 1101428189 by Ascax (talk): trolling Tags: Undo Reverted |
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:Cranks are gonna crank. The article contains a perfectly cogent discussion of the speed of light in general relativity; the removed sections were entirely [[WP:SYNTH|synthesis from primary sources]]. Such a discussion (of early 20th century views on the speed of light) should instead be sourced to published literature on the history of science. If Unzicker wants to write such an article and get it through peer review at a real journal, more power to him; ranting youtube videos are not a substitute. [[User:JayBeeEll|JBL]] ([[User_talk:JayBeeEll|talk]]) 19:17, 26 July 2022 (UTC) |
:Cranks are gonna crank. The article contains a perfectly cogent discussion of the speed of light in general relativity; the removed sections were entirely [[WP:SYNTH|synthesis from primary sources]]. Such a discussion (of early 20th century views on the speed of light) should instead be sourced to published literature on the history of science. If Unzicker wants to write such an article and get it through peer review at a real journal, more power to him; ranting youtube videos are not a substitute. [[User:JayBeeEll|JBL]] ([[User_talk:JayBeeEll|talk]]) 19:17, 26 July 2022 (UTC) |
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::Everything removed from this article (repeatedly, and by multiple editors) was about ''something else,'' shoved in here in order to make borderline [[WP:FRINGE|fringe]] ideas look more respectable. [[User:XOR'easter|XOR'easter]] ([[User talk:XOR'easter|talk]]) 17:48, 27 July 2022 (UTC) |
::Everything removed from this article (repeatedly, and by multiple editors) was about ''something else,'' shoved in here in order to make borderline [[WP:FRINGE|fringe]] ideas look more respectable. [[User:XOR'easter|XOR'easter]] ([[User talk:XOR'easter|talk]]) 17:48, 27 July 2022 (UTC) |
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There is no serious controversy that Einstein advocated a variable speed of light in general relativity. |
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Editing on Wikipedia is for the improvement of articles. |
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Deleting, not improving, the contentious paragraphs, even when everyone recognizes that Einstein defended this position, constitutes vandalism. |
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I think the editors who removed these passages, instead of improving them, owe an apology. |
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I think an adequate apology would be to write up an acceptable version of Einstein's position on the variable speed of light, with the references. |
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If they make no effort to restore the truth of these historical writings, we can conclude that they edited Wikipedia with malicious intent, in order to reinforce their prejudices about the history of science. [[User:Ascax|Ascax]] ([[User talk:Ascax|talk]]) 00:04, 31 July 2022 (UTC) |
Revision as of 04:47, 31 July 2022
Physics: Relativity Start‑class Mid‑importance | |||||||||||||
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Einstein's view
Now that the Einstein digital papers are online, it's possible to search various papers to determine Einstein's opinion about the speed of light. For example you can find this where in the second paragraph Einstein says this:
"Second, this consequence shows that the law of the constancy of the speed of light no longer holds, according to the general theory of relativity, in spaces that have gravitational fields".
That wasn't written in 1911. It was written in 1920. I'm afraid it's a popscience myth, or a rewriting of history, to claim that Einstein abandoned the variable speed of light in 1911. You can find other examples yourself. Note that in some of the translations you see the word "velocity" instead of "speed". Some will tell you that this is the vector quantity velocity. It isn't, it's the common usage, as per high-velocity bullet. Have a read of this Baez article written by Don Koks for another example. See the general relativity section. JohnDuffield (talk) 19:14, 2 January 2015 (UTC)
All you need to do is look at the math in Einstein’s book "The Meaning of Relativity" 5th edition from 1953. A calculation of alpha (α) follows equation 107 and makes an unambiguous use of variable scalar light velocity (L) both as the argument of a partial differential function (proving a variable) and as the denominator in a fraction (proving not a vector) both in the same integrated quantity. Division by a vector is not defined, so there is no other way to interpret the velocity of light in this usage except as a variable scalar speed.
(1/L)(∂L/∂x1)dx3
In other calculations Einstein explained that he used velocity as a vector when it was measured as components of a coordinate system.
Peter Bergmann did not agree with Einstein, but left the dispute out of his earlier book "Introduction to the Theory of Relativity" 1942 to get Einstein’s endorsement. After Einstein died Bergmann wrote a new book "The Riddle of Gravitation" 1968 claiming that vector light velocity could change direction but not speed. This has become a prevailing opinion in science, but not in agreement with Einstein’s unambiguous math.
Max Born agreed with Einstein and very clearly stated both speed and direction of light change in a gravity field. Einstein’s Theory of Relativity 1923 in English, 1920 in German. Dover editions 1965 page 357. Astrojed (talk) 01:43, 24 June 2015 (UTC)
This article is aware in some places, and unaware at others, that "VSL" groups a number of completely unrelated proposal. This is of course a result of content-creep over time. Atm, I can see at least three unrelated topics here:
- "Einstein and Dicke" ideas of frequency/wavelength dependency of c: all criticism related to "but c is dimensionful" is off topic to this, because it is about an upper limit on the ratio of c of light of two different frequencies. If c were frequency-dependent, the SI definition would become meaningless unless a specific frequency was specified.
- massive photons: this is not a proposal that c as a fundamental parameter in relativity etc. is variable, but that actual light travels at variable speeds slightly below c. Again, this would be about the ratio of the speed of a given photon to c
- cosmological things: Here I am not sure whether "VSL" is just a convenient way of phrasing this for the purposes of cosmologists who are perfectly aware that their "variable c" is equivalent to a variation of alpha and/or G. The problem is apparently that the editors responsible for this section were themselves not sure/aware of this.
tl;dr / bottom line: it is useful to point out the "dimensionful" problem to the reader of the article, but it is beside the point to portray this as a "criticism" because it simply doesn't apply to any actual proposals discussed in the article. It also isn't possible to present any one "criticism of the VSL concept" because there isn't any single "VSL concept". --dab (𒁳) 13:58, 12 May 2016 (UTC)
Sign error in Dicke's refraction formula?
If c_0 is the speed of light absent of gravity, should not c --- the speed of light in presence of gravity --- be smaller? The formula then should rather have a minus sign as in 1-2GM/rc^2, converging nicely to 0 as r approaches the Schwarzschild radius r_s=2GM/c^2 from above? — Preceding unsigned comment added by 46.92.251.76 (talk) 08:20, 17 September 2017 (UTC)
Einstein's VSL - re:Unzicker's Real Physics video
As discussed in this YouTube video, it seems that mentions into Einstein's exploration of VSL have been unjustifiably removed. While I disagree with some of the language in the video, I think he demonstrated well that Einstein's VSL definitely belongs in this article. //Yuval Talya; My contributions; Let's talk// 10:50, 26 July 2022 (UTC)
- Cranks are gonna crank. The article contains a perfectly cogent discussion of the speed of light in general relativity; the removed sections were entirely synthesis from primary sources. Such a discussion (of early 20th century views on the speed of light) should instead be sourced to published literature on the history of science. If Unzicker wants to write such an article and get it through peer review at a real journal, more power to him; ranting youtube videos are not a substitute. JBL (talk) 19:17, 26 July 2022 (UTC)
- Everything removed from this article (repeatedly, and by multiple editors) was about something else, shoved in here in order to make borderline fringe ideas look more respectable. XOR'easter (talk) 17:48, 27 July 2022 (UTC)