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Einstein's train and platform
The following needs more explanation
For the observer standing on the platform, on the other hand, the rear of the train is moving (catching up) toward the point at which the front flash was given off, and the front of the train is moving away from it. As the speed of light is finite and the same in all directions for all observers, the light headed for the back of the train will have less distance to cover than the light headed for the front. Thus, the flashes of light will strike the ends of the train at different times.
For the speed of light is supposed to be relative to the observer.
From the train's observers perspective, the train is not moving. So why would the front flash be seen before the back one? (Einstein himself merely asserts it, and I suspect it is a fudge.) See the online reference to his work that I added.
Tuntable (
talk)
02:17, 13 November 2019 (UTC)reply
Yes, Einstein's original example with two flashes (in the first subsection
Relativity of simultaneity#Einstein's train and with the first figure on the right) is different from the one we have here. Here in the second subsection (
Relativity of simultaneity#The train-and-platform) we have one flash from the center of the car, as explained in the second figure on the right and in the the cited sources. This was discussed before—see the archive of this talk page. I have restored the original content. -
DVdm (
talk)
07:52, 13 November 2019 (UTC)reply
Students do not understand Einstein's train
They cannot understand it because the concept of relative simultaneity is full of errors.
[1]
see
See Scherr et. al.
References
^"The results indicate that after standard instruction students at all academic levels have serious difficulties with the relativity of simultaneity and with the role of observers in inertial reference frames. Evidence is presented that suggests many students construct a conceptual framework in which the ideas of absolute simultaneity and the relativity of simultaneity harmoniously co-exist."
They cannot understand it because the concept of relative simultaneity is full of errors. That is not what the paper you linked says.
VQuakr (
talk)
09:18, 1 February 2020 (UTC)reply
Errors
The equations for the Lorentz transformation involve t − vx/c2, which is correct, but the associated text is changing the x to a subscript, i.e. t − vx/c2, thus making it incorrect. Unless someone can explain this mixup then I will proceed to rectify the text.
TonyP (
talk)
16:55, 26 July 2022 (UTC)reply
User
Fjeowu (
talk·contribs) added a remark about Poincaré in the lead (
[2]). I undid the edit (
[3]) because, as I explained in the edit summary, I think this does not belong in the lead. Poincaré's role is amply mentioned in the history section. User Fjeowu then reverted again (
[4]) with (i.m.o. misguided, possibly
assuming bad faith from my part) remarks about Einstein being made a super hero of some kind. I warned user Fjeowu on their user talk page about edit warring. Comments welcome. -
DVdm (
talk)
17:55, 5 October 2022 (UTC)reply
Absolutely a good inclusion. @
DVdm: there's still time for you to self-rv your removal. Since the lead is effectively missing from this article I would suggest holding off on the undo button as much as possible when it comes to expansion of the lead section.
VQuakr (
talk)
18:43, 5 October 2022 (UTC)reply
L If you want to balance out the credit, then I would suggest removing the extraneous "Einstein" from the beginning of the Description section. The History section is fairly thorough.
Roger (
talk)
23:00, 5 October 2022 (UTC)reply
Mentioning only Poincaré and no one else is not in line with
the Manual of Style. As it stands, the lede doesn't even attempt to fairly summarize the body. A lede that mentions no individual scientists at all would be better than what we have now, though a fuller lede would be better still. Right now, it's in an awkward local minimum.
XOR'easter (
talk)
18:43, 7 October 2022 (UTC)reply
I fail to see how that policy is relevant. Using the only part of the page that many readers will read to tell half the story — and in a POV-pushing way, at that — isn't better than waiting to tell the full story. Right now, the article has a major
Undue weight problem, which is explicitly listed in the
Wikipedia:Editing policy#Problems that may justify removal section of that policy page. Sometimes the quickest fix is the Backspace key.
XOR'easter (
talk)
17:00, 8 October 2022 (UTC)reply
The body mentions Lorentz, Poincare, Einstein, and Minkowski. The concept is chiefly due to Poincare. The lede could mention all four, but if it mentions one man, it should be Poincare.
Roger (
talk)
20:44, 9 October 2022 (UTC)reply
If it mentions one man, it should be Einstein, who developed the full theory that provides a detailed accounting of the concept. Predecessors are trivia by comparison. (The introduction to
calculus mentions Newton and Leibniz but not Archimedes, and this is as it should be.) I could see a case for mentioning all four, or possibly for omitting Lorentz. The main text could be expanded to include, e.g., Reichenbach and Whitehead, but I doubt that they'd make the intro.
XOR'easter (
talk)
19:07, 10 October 2022 (UTC)reply
Archimedes did not find the equations and formulas that Newton and Leibniz did. Lorentz and Poincare had all of the relativity simultaneity formulas before Einstein. See the History section for a good summary of what each did. The lede should just summarize. You could say that Minkowski had the full theory.
Roger (
talk)
00:00, 11 October 2022 (UTC)reply
Having the formulas doesn't mean having the concepts (as the History section already notes). Maybe others feel differently, but I tend to find that an accurate treatment of the history of a scientific subject can quickly become a tangled mess. Who had which part of which idea in what year? What now-forgotten philosophy did they subscribe to? Etc. I think that expanding what the intro has to say about the concepts and the mathematics is more likely to be helpful.
XOR'easter (
talk)
01:35, 11 October 2022 (UTC)reply
Conjugate diameter and
conjugate hyperbola both remark on their role in the subject of this article. An editor has reverted a contribution, asserting original research. The images in use show leaning and
hyperbolic rotation is linked in the contribution. The assertion is false, and the contribution should be restored.
I
undid the modification fof the lead, as I found the wording unusual and leaning to original research. For instance, regarding the phrase "A diameter of one hyperbola reflects into a diameter of the other", there is nothing about that in Whittaker.
The tag requests an expanded lede, and that part of an article is to describe the whole. As it is, much of the article recounts the various attempts to comprehend Minkowski's notion. The classical geometry of conic sections treats conjugate diameters, which Whittaker recognized in Minkowski's algebraic statement as a vanishing bilinear form. The analytic geometry of conjugate diameters of a hyperbola (and its conjugate) has been written at
hyperbolic orthogonality, with references. The relativity of simultaneity concept is transparent when associated with the classical geometrical symmetry. —
Rgdboer (
talk)
02:20, 14 February 2024 (UTC)reply
Sure, but expanding the lead with content that is not in the article is not the way to go. If content is missing, it should be put in the article body, together with the relevant sources. Only if there is sufficient of it, it can be very briefly mentioned in the lead, as is explained in the guideline
wp:LEAD. -
DVdm (
talk)
03:01, 14 February 2024 (UTC)reply
To echo this - the lead needs to summarize the body. Mention of Minkowski in the lead probably makes sense but the proposed diff? Nah. Not even close.
VQuakr (
talk)
05:35, 13 March 2024 (UTC)reply
But then a month later,
this with an edit summary "Undid revision 1206155316 by DVdm (talk)per Talk". Per lack of conensus on talk perhaps? User Rgdboer warned for edit warring:
[5]. -
DVdm (
talk)
06:21, 13 March 2024 (UTC)reply
In the revert of 11 February the edit summary says the new lede is unusual, unsourced, or OR. The discussion was initiated by me. See
Spacetime_diagram#Minkowski_diagrams for an expression of the relevant geometry, which is well-known. The terms are found in the article, so new matter was not introduced. A month seemed long enough to appreciate Minkowski's relativity of simultaneity by geometrical symmetry. BTW alternate editors indenting alternately, commonly used in Talks, saves screen space. —
Rgdboer (
talk)
01:47, 16 March 2024 (UTC)reply