Talk:Lorentz transformation/Archive 7

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Derivation

This is copied from my talk page:

Re: your edits to the Lorentz transformation article...

Not only isn't it the case that "From Einstein's second postulate of relativity follows immediately", but it doesn't follow at all! Rather, it follows from simple algebra (as I showed in the edit you deleted). Einstein's second postulate doesn't figure into it until later in the transformation.

Ross Fraser (talk) 03:47, 11 January 2016 (UTC)

You showed the interval is invariant for light signals. From this you cannot infer directly that it holds for all intervals. This is showed in my version of it in the linked article. You simply require (without proof) that it holds for all intervals. This is a standard undergraduate textbook shortcut. It is also revealing that you claim that the second postulate is not required for the invariance of lightlike intervals. YohanN7 (talk) 10:09, 14 January 2016 (UTC)

My take on this is that the "standard recipe" in undergraduate textbooks is endowed with too many gaps. That the interval is invariant for light signals is a trivial consequence of postulate two, while the invariance of every interval takes a derivation. (The present proof has gaps too, but these are less severe. Namely, what guarantees that every LT is found in this way.) YohanN7 (talk) 10:17, 14 January 2016 (UTC)

"absurd physics" – a critique

just found → this on linkedIn. the diagram seems indeed flawed. please inspect things. best, Maximilian (talk) 11:46, 18 August 2016 (UTC)

Seems very reliable. The author also writes

I am busy with a loong manuscript in which I am doing the mathematics in detail and show that QM and relativity flow seamlessly from Newton's laws (when corrected for mass increase) and Maxwell's laws. Physics has been unified since Maxwell, when not believing the absurd nonsense like "time-dilation" and Schroedinger's cat being alive AND dead!

My sentiments exactly. YohanN7 (talk) 12:39, 18 August 2016 (UTC)

Extreme misuse of LinkedIn Stigmatella aurantiaca (talk) 13:24, 18 August 2016 (UTC)

How is the diagram flawed? It just shows what each observer measures in their frame. Let's see Maximilian's explanation for the flaw in this diagram. M∧Ŝc²ħεИ_τlk 15:25, 18 August 2016 (UTC)

The author seems to disagree with SR and emphasizes Galileo-Newtonian mechanics (see for example [1]). I still don't understand the explanation about the Lorentz transformations... M∧Ŝc²ħεИ_τlk 16:02, 18 August 2016 (UTC)

Debunking antirelativists is highly off-topic here. Let's try to confine it to LinkedIn or to Usenet. Or to Speaker's Corner. - DVdm (talk) 16:15, 18 August 2016 (UTC)

@DVdm: Not trying and debunk Johan Prins here. I simply commented on the fact that he is an "antirelativist", and has written a long rambling incomprehensible "critique" on the LTs. (Even trying to make fun of my diagram in the process, and tar it and WP and the literature with $h!t - not that I care). Also, I simply asked if Maximilian had his own explanation to offer, if any.

@Maximilian Schönherr: No worries and thanks for pointing this out. M∧Ŝc²ħεИ_τlk 17:54, 18 August 2016 (UTC)

that's fine with me. i guess, after some inspection, that mr. prins runs conspiracy theories, so let's ignore this. Maximilian (talk) 17:17, 18 August 2016 (UTC)

Quite. I had a good laugh too . - DVdm (talk) 20:05, 18 August 2016 (UTC)

I think it is a very good exercise of one's understanding of relativity to find the flaws in antirelativist arguments. Some are very subltle and instructive. But this is just too long winded to pick apart. Which is not to say he doesn't have a point. One fundamental flaw is the idea that an event occurs in a particular inertial reference frame (IRF). An event is a point, it has no extension in space or time, and cannot specify, or be considered to be "in" one IRF but not another. The equivalent statement in spatial geometry is that a point cannot specify a set of coordinate axes, nor is its nature or existence dependent upon a choice of coordinate axes. PAR (talk) 01:22, 19 August 2016 (UTC)

We all seem to agree. But I object to even posting here that there are conspiracy theories (or whatever it happens to be) floating around on the internet. It invariably costs people time. Quoting DVdm, "debunking antirelativists is highly off-topic here.", right - but it is also near impossible to debunk them. The people behind conspiracy theories are often not psychologically well. They may be intelligent, but they are unable to listen and learn. If they are psychologically well, they do what they do because they like to mess with people. They like the attention. Yet so, it is hard to resist debunking. This is why I strongly recommend posting links to such theories should be refrained from - even as a good joke. YohanN7 (talk) 08:29, 19 August 2016 (UTC)

I agree. And re "but it is also near impossible to debunk them": actually, it is not just near impossible—it is completely impossible. That's why we don't do that here. - DVdm (talk) 09:13, 19 August 2016 (UTC)

Yes. I strayed off subject - This page is not the place to consider antirelativist theories. A link to an antirelativist wikipedia page is all that is needed. Such a page would, in effect, reveal the errors in thinking , which I fully expect, but do not presume apriori, to exist, of more or less intellectually honest antirelativists, and maybe some comment on the whackazoids. This would be constructive to anyone learning relativity. I don't agree with the generalization that all antirelativist theories are generated by nut cases and are uniformly undebunkable. This smacks of an unscientific "belief" in relativity, rather than the scientific attitude of tentative agreement. PAR (talk) 09:25, 19 August 2016 (UTC)

Readibility problem

Was just reading the article today, found it quite easy to follow, well done. About half way down the formulas are printed as formatting instructions and the article becomes unreadable, just thought you should know.

23 October 2016 AbsoluteZero01 AbsoluteZero01 (talk) 20:29, 23 October 2016 (UTC)

@AbsoluteZero01: everything looks ok here. Exactly where does it go wrong? Which OS? Which browser? Which setting do you have in Preferences, Appearance, Math? - DVdm (talk) 20:38, 23 October 2016 (UTC)

Just checked the article again, it seems fine, the formulas from the Tensors section to the end of the article appeared in formatting text only and could not be read, I don't know what the problem was but it seems OK now. I have never had this with any other article, so I doubt it was at my end. I'm using Firefox, Windows 10, English, Times New Roman. Maybe just a temporary glitch. Thanks for replying so quickly. I can read the rest of the article now. Thank you.

23 October 2016 AbsoluteZero01 AbsoluteZero01 (talk) 22:09, 23 October 2016 (UTC)

Temporary glitch, no doubt. - DVdm (talk) 06:40, 24 October 2016 (UTC)

Simple inference of Lorentz Transformations due to Time Dilation

This derivation is intended for lay readers, which is why the math is explicitly spelt out, and the derivation makes no reference to more advanced topics like 'frame', 'light cone' 'boost velocity' and the like. Indeed it uses no words or terms that are not fully defined within the section, apart from 'space', 'time', 'velocity' and gamma which is derived and defined in the Simple Derivation on the time dilation page.

This is by design.

The intent is that a lay reader may fully understand the lorentz transforms with only a passing knowledge of time dilation. I have therefore added it at a similar position to the Simple Derivation on the Time Dilation page.

I am working on adding the simplest possible space time diagram, to accompany this derivation, in the hope that I may be able to make it less verbose. For the meanwhile: you may find my choice of language a little "old school", but I believe it is the minimal set of words for the proof to be both immediately clear to anyone, and formal. Perhaps modifications should be discussed here first.

That being said, please do expand, clarify or correct it wherever you deem appropriate, particularly any typos that may have crept in while marking this up. Improvements on my rudimentary markup skills are also very welcome. I have checked the presentation as well as I am able.

If anyone can also tell me whether they have seen this derivation before, or if indeed it is likely to be novel, I would be most grateful. A question has been asked on Talk:Derivations of the Lorentz transformations (where you can see preceding discussion) as to whether this derivation would then constitute original research, which is against policy (thank you so much User:DVdm), to which I humbly suggest that this is simply a rearrangement of information already present on the Derivation of Lorentz Transforms page, and also this page, and the dozens of references therein, and also this one that I have just found [[2]] rather than original research per se. The search term I used to find that reference was 'minimal derivation of lorentz transformations', in case you are interested in ferreting such references out. If you have better luck finding a more direct reference than I did, then I would very much like to read it, and will happily add the reference note myself. This is my third post on this site, so my apologies for any unwitting breach in etiquette. Respectfully, Kebl0155 (talk) 17:49, 12 January 2017 (UTC)

I have removed ([3]) the addition per elementary policy wp:unsourced and wp:no original research. We can't have this, as I explicitly told you here. - DVdm (talk) 18:24, 12 January 2017 (UTC)

My sincere apologies for any offence caused. I had thought the reference given above would be sufficient. I will see if I can find a better reference for it. It appears I have been overly bold after all. I hope you do not think me a vandal. I will certainly not repost the section unless or until confirmation of a sufficiently strong reference has been obtained. I would be interested to know your thoughts on the derivation itself. Also, if it's sufficiently original to be unpostable here, does that mean it is original enough for the notion of publishing a paper to be considered? It would be my first, and I don't know how to go about doing that. I defer to your judgement on appropriate action. Very respectfully, Kebl0155 (talk) 18:52, 12 January 2017 (UTC)

No problem, no offence at this point. We can't comment on the derivation itself, as that would be against our wp:talk page guidelines. - DVdm (talk) 19:57, 12 January 2017 (UTC)

Thank you for that. I am partially reassured. I have moved from feeling very discouraged to neither discouraged nor encouraged, but still also perhaps overly cautious, and quite uncomfortable. I retract my specific question on your thoughts, of course, and further apologise for having asked it. I remain very new. The etiquette guidelines do say that talk pages are an appropriate place to provide comfort to damaged egos; though perhaps you may choose to move this conversation to my personal user page instead, as that's all a bit personal. I am going to carefully think about what my next questions on this matter might be, and will do my best to confine them to topics you may be able to answer, so this is probably the last post you'll see from me 'til tomorrow. I would like to leave you with my sincere thanks for the time you have spent in conversation with me over the last few days, particularly given my newness. Respectfully, Kebl0155 (talk) 20:53, 12 January 2017 (UTC)

This article is about the LT and its properties. Derivations of the LTs are for the Derivations of the Lorentz transformations article. No derivations of the LTs should be in this article. M∧Ŝc²ħεИ_τlk 08:47, 13 January 2017 (UTC)

I agree. And that article is more or less at the brink of overflowing... - DVdm (talk) 09:24, 13 January 2017 (UTC)

Thank you all for sharing your thoughts. In point of fact, there is a derivation on this page, in the Derivation section. It is incomplete and inpenetrable to the lay reader. Is that really as it should be? Should that section simply be removed? Or should it be replaced with a derivation that is short, complete and easy to follow? I'm not suggesting that the one that I have presented should be that one; I'm simply asking three specific questions as to whether this page is maximally beneficial. I would argue that it is not. Respectfully Kebl0155 (talk) 10:26, 13 January 2017 (UTC)

The section Lorentz transformation#Derivation is obviously not a derivation. Just a section which shows the starting point to derive the LTs. It made no sense at all to put your edit before this section, which is just one of many ways (tens? hundreds?) to derive the LTs. That is the whole point of having a separate article for derivations. M∧Ŝc²ħεИ_τlk 10:34, 13 January 2017 (UTC)

Let's take my edit off the table. This is not about me. It is reasonable to suggest that the words "Finding the solution to the simpler problem is just a matter of look-up in the theory of classical groups that preserve bilinear forms of various signature. The Lorentz transformation is thus an element of the group O(3, 1) or, for those that prefer the other metric signature, O(1, 3)." at the end of the derivation section does constitute a derviation. Its brevity makes it look a little hand-wavy to the untrained eye, but I expect you would have no trouble convincing me that the full form is not at all hand-wavy; it just does not appear here. It also does not appear on the Derivations page, so my expectation is based purely on trust at this point. It may appear on the Lorentz group page; the necessary group theory is quite beyond my competence to comment further.

I can see that the Generalities section that immediately follows does expand upon the notions introduced in the Derivations section. I can't see that much else on the page relies upon it; that may be a failure in my sight.

The question I am asking is: When a lay reader searches for Lorentz Transformations, is this really the first thing they should see? No-one has answered that. Respectfully Kebl0155 (talk) 11:03, 13 January 2017 (UTC)

The alternate contention that the Derivation section does not contain a derivation, as asserted above, is easily resolved; I have applied a simple fix. My question still stands. Kebl0155 (talk) 11:26, 13 January 2017 (UTC)

Please refrain for editing a t m. You have blanked the section. YohanN7 (talk) 11:35, 13 January 2017 (UTC)

The section does contain a derivation of the set of Lorentz transformations. They are by definition the ones preserving the interval. The only argument one can raise is that it is not proved that all transformations preserving the interval are found this way. This is at least dealt with. Partly by exposing the spacetime translations (which do preserve the interval) and partly by (in footnote) exposing the conformal transformations that do preserve the interval, but for lightlike separated events only.

This section is purely neutral because it is mathematical. It relies on no physical experiment of thought. This is a strength, not a weakness, and it should definitely stay. YohanN7 (talk) 11:50, 13 January 2017 (UTC)

I had merged it into the Generalities section (at least I thought I had). I didn't realise you were also making edits at this time. My apologies. If the Derivation section does not contain a derivation, it should be called something else; otherwise it is misleading. I am not alleging any ill intent with that; just pointing it out. Am I out of line to also point out that these sections contain no references? Are they original research? Kebl0155 (talk) 11:57, 13 January 2017 (UTC)

The derivation of all Lorentz transformations is there, just in front of your eyes.

No, it is not original research. It is verifiable, and the distinction between verifiable material and original research is that the former can be referenced to a reliable source, while the latter can not. There is no requirement that citations are in place for anything and everything. but anyone can demand it. But "demanding it" (by placing templates) should be kept to a minimum, because it tends to make article look like the inside of a brothel. Better is to put in citations yourself or take it to the talk pages. YohanN7 (talk) 12:33, 13 January 2017 (UTC)

Thank you for this clarifying note and your wonderfully lurid simile, which made me smile. When making my edit, I had taken my cue from these two sections, so I feel less embarrassed about that now, and am correspondingly grateful for your kind words. If my attention had been brought to the Citations guidance, I may have gone about things differently (User:DVdm your actions have been unfailingly kind, and I thank you whole-heartedly for that; perhaps as part of your kindness you might consider referring to these alongside the Reference guidance to newbies like myself in future to save embarrassment). I assert that my edit is/was eminently verifiable; I should none the less back that up before considering it further. I do accept the arguments that this is not the right page; had they been presented earlier, I would not have posted here. Indeed I am glad that we have now had this conversation, and that matter has been debated and agreed. I do not intend to discuss that matter here further. I will take it on trust that the mathematical derivations of all Lorentz Transformations are there in 'just in front of my eyes' (also very pleasing). I also whole-heartedly approve of the renaming of the Derivations section, and the immediate link to the Lorentz Group, which seems to have recently taken palce. Bravo. Thank you again. Kebl0155 (talk) 13:18, 13 January 2017 (UTC)

What is not there is an explicit connection between elements of the representative matrices $\Lambda$ and physical quantities, i.e. how the boost vector ${\boldsymbol {\beta }}$ and vector of rotation angles ${\boldsymbol {\theta }}$ relate to matrix elements. This is displayed in Lorentz transformation#Proper transformations in the case of pure boosts, but not derived anywhere in this article. I presume that that is what you mean by a "derivation". I'd certainly agree that that would be a derivation of a particular Lorentz transformation, e.g. in the case of a pure boost in the x-direction. But we have previously agreed the latter is relegated to Derivations of the Lorentz transformations. (There all mention of matrices is absent though. But the connection between matrix elements and the "Standard configuration boost" is fortunately rather trivial.) YohanN7 (talk) 13:46, 13 January 2017 (UTC)

I'm not knowledgeable enough to know whether that is what I meant by my earlier statement. That's not a sarcasm; it is a genuine acknowledgement of my limited ability. It could well be. I was earlier talking about language; I'm happy to leave the matter settled. Humbly Kebl0155 (talk) 14:13, 13 January 2017 (UTC)