Talk:Mach's principle

message: This article needs to be entirely rewritten to 
*take account of the fact that many distinct ideas have been called "Mach's principle", leading to much confusion in the literature,
*give an accurate account of how these are/are not validated in gtr and other major theories,
*give pointers to the most useful references in the literature, especially recent volumes/reviews.
For now I have just added a few citations---CH  (talk) 04:22, 18 August 2005 (UTC)
replies: text: The second paragraph "The idea is that the local motion of a rotating reference frame is determined by the large scale distribution of matter, as exemplified by this anecdote:..." is not really correct. Rotating reference frames were a key motivation for Mach and Einstein, but Mach's principle is not limited to rotating frames. Actually, since the term "Mach's principle" was (as stated correctly) coined by Einstein, and all the subsequent literature is related to it, it might be good to paraphrase Einstein's definition. The original definition by Einstein (in German) is from his 1918 paper on GR [Einstein, A.: Prinzipielles zur allgemeinen Relativitätstheorie. Ann. Phys. 55, 241–244 (1918)] and can be found translated in several secondary references, e.g. the section by C. Hoefer in Ch.1 of Barbour & Pfister (eds.) "Mach's principle" (ref. 6), in particular p.77: "Mach's principle: The G-field is without remainder determined by the masses of the bodies. Since mass and energy are, according to the results of the special theory of relativity, the same, and since energy is formally described by the symmetric energy tensor T_{\mu\nu}, this therefore entails that the G-field be conditioned and determined by the energy tensor." [G-field=gravitational field=metric tensor]. I would suggest to correct the relevant sentence by writing something in the style of: "The idea is that the geometry of the universe, and hence the definition of inertial reference frames, is determined by its mass distribution. As Einstein himself put it: The gravitational field is without remainder determined by the masses of the bodies. [cite ref. Einstein 1918 mentioned above]." A key issue and crucial motivation for both Mach and Einstein was the question of absolute and relative rotation, as exemplified by the following anecdote..." (although honestly I am not convinced that this anecdote is very much to the point, and sounds pretty much like "original inspiration" of whoever wrote this - I have certainly not seen it being mentioned anywhere in the literature on Mach's principle). Imtg5102 (talk) 08:22, 14 April 2012 (UTC)
replies: text: I'm pleased to see that the above comment gives a precise reference for the original coinage of the term by Einstein.  I was specifically looking for this, and frustrated not to find it in the article itself.  At present it just states that Einstein coined the term in 1918.  It would be useful for someone who knows the Wiki ropes to insert a reference into the article.109.148.240.238 (talk) 20:58, 19 February 2020 (UTC)
thread_title: This article needs much improvement

message: The article is currently very confused about whether the quote is due to Einstein or Mach himself.  In fact I think it is probably due to Born!  Whoever wrote this, please fix!  TIA ---CH 21:33, 24 December 2005 (UTC)
replies: text: Seems to me that this problem is solved and so this remark can be removed. Imtg5102 (talk) 08:22, 14 April 2012 (UTC)
replies: text:  Actually, I am trying to find the quote referenced by note n. 6 both in the main English translation and in the original German text... but I am utterly unable to find it. It seems like it ether comes form Einstein or from an unofficial translation of Mach.151.61.65.209 (talk) 13:37, 30 March 2021 (UTC)
thread_title: Misattribution?

message: I extensively edit the August 2005  version of this article and had been monitoring it for bad edits, but I am leaving the WP and am now abandoning this article to its fate.
Just wanted to provide notice that I am only responsible (in part) for the last version I edited;
see User:Hillman/Archive. I emphatically do not vouch for anything you might see in more recent versions.
Be aware that Mach principles (see the arXiv eprint by Hermann Bondi for the plurality of Mach principles), is one of the most contentious topics in gravitation physics.  Unfortunately, several WP editors have attempted in the past to slant this and related articles to present their own idiosyncractic view as the only view, or have suppressed the fact that this topic is highly controversial (or have simply unbalanced coverage by presenting far more information about their particular view than about the dozens of alternative views).
Good luck in your search for information, regardless!---CH 01:57, 1 July 2006 (UTC)
thread_title: Students beware

message: Mach's principle is a particular statement—the content of which is, unfortunately, very vague.  On the other hand, a Mach principle is any statement (hopefully less vague) which either is, or pursues the spirit of the original Mach's principle.
"A Mach principle" is syntactically and semantically distinct from "Mach's principle".  The class of principles qualifying as Mach principles deserves its own page, as does the historically important and distinct Mach's principle.  Thus, I have killed the redirect on Mach principle and put some distinct and (hopefully) useful information on that page.  I think it is very useful to have one page dedicated to the history of this notion, and one to the jungle of statements which have actual scientific value.  MOBle 01:11, 24 August 2006 (UTC)
replies: text: As I am not a native English speaker I do not understand in full what "Mach principle" in fact means in this context. I wrote both articles for sl WP from English versions and named second term as "Machian principle" (Slovene machovsko načelo) in similarity to Euclidean space (evklidski prostor) (in contrast to Euclid's lemma (Evklidova lema) or Euclid number (Evklidovo število)) and such - but I am not sure if this naming is correct. Are terms "Mach" and "Machian" in this case equivalent? --xJaM 14:19, 12 October 2006 (UTC)
replies: text:  The difference in meaning is only very subtle, so it's mostly just an issue of style.  I think I might actually prefer "Machian principle" slightly, but others had already used "a Mach principle", so I figured we should stick with that, here.  I'm not committed one way or the other for the English, and I guess you should use whatever sounds best in Slovene.  My only concern was to clarify the distinction between history and science/philosophy.  --MOBle 17:49, 12 October 2006 (UTC)

text:  I see. I understand your concern for the distinction. Here I also see one difference between English and Slovene in one another example: a term Galilean transformation is in Slovene in fact named Galilei('s) transformation (Galilejeva transformacija and not galilejevska ~). Further on Lorentz transformation in English is not called Lorentzian. Perhaps I didn't choose the best example, because "Galilean" here might in fact mean "Galilei('s)", but also it can be one speciality in English. --xJaM 11:15, 13 October 2006 (UTC)

text: I would like to say that I would have personally found it extremely helpful to find the  material under Mach principle on Mach's principle and I therefore support the merge. 1Z (talk) 13:24, 4 January 2011 (UTC)
replies: text:  Regardless of syntactical or semantical concerns, wikipedia should reflect the common habits of professional literature on Mach/Mach's/Machian principle. To my knowledge, there is NOT A SINGLE of the dozens of academic articles and books on Mach('s) principle that makes a distinction between Mach principle, Mach's principle or a Machian principle, and the preferred term (actually the ONLY ONE used in the professional literature, as far as I know) is "Mach's principle", since this was the original term coined by Einstein. For example, Julian Barbour, the leading expert on the subject and editor of the standard book "Mach's principle" (cited as ref.6 in the "Mach's principle" article), systematically refers to "Mach's principle", even when he explicitly reformulates it within the contect of his own theories (see his recent "The Definition of Mach's Principle", Foundations of Physics 40 (2010) 1263-1284; http://arxiv.org/abs/arXiv:1007.3368). Even the article by Bondi and Samuel which is cited in the "Mach principle" article as the main inspiration to distinguish between "Mach principles" as opposed to "Mach's principle" actually does not use the term "Mach principle" but only "Mach's principle". This distinction is therefore confusing, contrary to established standards and should, IMHO, be removed (i.e.: the article "Mach principle" should disappear). The paragraph "Examples" from "Mach principle" could be integrated into the article on "Mach's principle". Imtg5102 (talk) 07:17, 14 April 2012 (UTC)
thread_title: Mach's Principle v. Mach Principle

message: Archelon removed the following paragraph:
It is very easy to understand that we need some metrical system which consist of mutually related parameters (or observables) and to pin somehow one end of such proportions to some datum-point. This process is very well visualised in crystalization process when we have some initial place in the space where crystalization starts (this place can be called as a datum-point of crystalization). And the rest of the system is affected and obeys some rules created at that initial datum-point.    
(It had apparently persisted for about a week).  The paragraph is not claimed to be nonsensical, though it is worded a bit obscurely; but it makes no sense in the context where it was inserted. 
Archelon 00:23, 18 February 2007 (UTC)
thread_title: Removed paragraph

message: Is there general agreement that this 'Pseudoscience Infobox' is appropriate here?  Certainly at least some Mach principles do not fall under the heading of pseudoscience, disputed though all of them may be.  Archelon 00:27, 18 February 2007 (UTC)
thread_title: 'Disputed Science'

message: There is a great preprint on the arxiv "Mach's Holographic Principle" by Khoury and Parikh (http://arxiv.org/abs/hep-th/0612117). There Mach's principle is taken to mean the idea that inertia is determined entirely by the 
matter content in the universe. 
The common objections general relativity being Machian, it is argued within,
essentially boil down to the fact that one, in solving GR's field equations, is allowed to 
select initia data for the induced metric and extrinsic curvature completely independently of the 
matter on the initial surface/boundary. 
Therefore, the geometry (given by the metric) defines inertia (acceleration is defined with respect to the geodesics
of the spacetime). However, in GR this geometry is determined not just by the matter (via
the Einstein field equations) but also by arbitrarily chosen initial conditions.
A process of replacing the initial conditions by boundary matter so that inertia is determined
entirely by matter content, is described. HaludzaHaludza 10:44, 20 April 2007 (UTC)
thread_title: 'Mach's Holographic Principle"

message: I see no reason to describe this subject as pseudoscience.  What justification is proposed for the pseudoscience box.
Martin Hogbin (talk) 20:25, 17 January 2008 (UTC)
thread_title: 'Disputed Science???'

message: I propose to delete the pseudoscience box.
Martin Hogbin (talk) 09:18, 18 January 2008 (UTC)
thread_title: 'Disputed Science???'

message: Why would Foucault’s pendulum oscillate inside a thick rotating sphere?  Oscillation is driven by gravitation, and gravitation inside the sphere cancels out, doesn’t it?  --Yecril (talk) 20:12, 19 October 2009 (UTC)
thread_title:  Foucault’s pendulum 

message: I wonder how this principle can have a meaning with actual quantum gravity and origin of inertia in particle physics, and wht about locality, GR is very very local. (To me this problem looks the same as current induction in electromagnetism). An experiment in GR can be made locally, and the centrifugal force depends on the speed of spining that can be experienced locally, and so with or without mass it is always the same locally. Where relative motion to define centrifugal force must appear is between particles which are part of the spining body. Could a single particle spining in an empty universe exist? I see no objection in a classical universe, the spining particle would create radiation because there are not only gravity!!!! the particle should have an energy lost in radiation,(excepted if the universe is closed, radiation could come back). But what is the meaning for a single point particle that doesn't radiate and has really not any spatial extension? It doesn't mean a lot I guess. Now my point is in particle physics we use the higgs to generate mass, and it is local, it doen't need far stars, I will search for link between graviton and higgs, a friend of mine had already talked to me about that, I hope I asked myself too in vague terms before, BUT a priori the higgs are not graviton, and even if they were we don't need far stars to generate inertia. More, in a quantum universe, with quantum fields, a single particle can't exist, then there exist always a relative motion and then relative relative motion => accelerations, I didn't say it was why we need quantum, but quantum field theory looks to be a "relation" theory (or interaction), that's what we need no? like it is wrote in the article.
So far stars are far.Klinfran (talk) 01:48, 8 January 2010 (UTC)
thread_title:  particles 

message: space existence cannot be imagined,no body in this world can exactly say how the space came into existence.Time and space are in same dimension.  — Preceding unsigned comment added by 123.201.131.2 (talk) 06:09, 22 February 2019 (UTC)
replies: text: g, vague, unclear, not logical proression to conclusion Juror1 (talk) 15:13, 16 June 2017 (UTC)
thread_title:  Answer 

message: As an interested non-physicist (student of Berkeley, Kant and Hegel) I found most of the article comprehensible and stimulating. But the last two paragraphs descend into incomprehensible gobbledygook, either willfully ("This section reserved for members only") or (more likely) because the author was unsure what point he or she was actually trying to make. Please revise or omit.66.108.110.211 (talk) 09:20, 12 June 2011 (UTC)
thread_title:  Rewrite or omit last two paragraphs (starting with "Initial Value Problem"). 

message: With all due respect for Asghar Qadir, his reference needs to be removed. Apart from the fact that these are hand-written slides, they actually have nothing to do with Mach's principle but with quantum non-locality (the correct title of the document is "Quantum non-locality, Black holes and Quantum Gravity", not the one given here). Also Vishwakarma's reference is not very relevant, since it is related to a very particular use of Mach's principle. I would be good to add "Barbour, Julian; and Pfister, Herbert (eds.) (1995). Mach's principle: from Newton's bucket to quantum gravity. Boston: Birkhauser. . (Einstein studies, vol. 6)" (ref. 6 in the main text), as well as a more recent article by Barbour (the undisputed expert on Mach's principle): Julian Barbour, The Definition of Mach's Principle", Foundations of Physics 40 (2010) 1263-1284; http://arxiv.org/abs/arXiv:1007.3368. Although the definition given there is a rather peculiar one, the article contains an excellent and very readable account of Mach's and Einstein's motivations. Imtg5102 (talk) 08:22, 14 April 2012 (UTC)
thread_title:  Further reading 

message: I have deleted that section for several reasons.  Firstly it was completely unreferenced.  The title is not that most commonly used for the general subject; it is usually called Newton's bucket.  The resolution referred to some specific assumptions about GR. It is in the wrong place, it would better form part of the history of the subject.
I intend to add more material to this article, including Newton's bucket, taken almost exclusively from the book "Mach's principle from Newton's bucket to quantum gravity".  I think it is OK to do that, the book consists mainly of a number of papers by experts in the subject and is by far the most comprehensive reference work on the subject.  Martin Hogbin (talk) 13:09, 12 March 2014 (UTC)
thread_title:  The Spinning Bucket paradox 

message: There are two separate pages! Will bring in the few lines from there. No point in two spellings, except confusion.  A tensor a day... (talk) 14:42, 24 November 2015 (UTC)
thread_title: Mach's vs Mach 

message: Now that I have read this page, I see so many problems in it. By the way, the idea was mentioned in the NY Times today, and the page is in a very sad state. Will try a few fixes, but it is mostly throw away material in this page now. A tensor a day... (talk) 14:42, 24 November 2015 (UTC)
replies: text: Wow. What a mess. Good luck with the pruning. Remember that everything is saved in the history, so you can be quite WP:BOLD in doing so. -- The Anome (talk) 15:01, 24 November 2015 (UTC)
replies: text: I will try to be bold after my tears have dried following my reading of this page. Even key items like the famous paper which relates to the  letter of Einstein to Felix Pirani mentioned in the NY Times article are not in this page now. Will try to delete some material and add a better, but necessarily shorter, summary for now.  A tensor a day... (talk) 15:36, 24 November 2015 (UTC)
thread_title: Oh Mach oh Mach... 

message: Substituted at 22:44, 29 April 2016 (UTC)
thread_title: Assessment comment

message: FYI, the book Misner Thorne Wheeler contains a facsimile of Einsteins letter to Mach. Legible, but its not a terribly good image, though.67.198.37.16 (talk) 23:17, 1 May 2016 (UTC)
thread_title:  einstein's letter to Mach 

message: Newton's bucket and the Michelson-Morley experiment led to lively discussions in the scientific scene of the time around 1900 and in particular inspired Albert Einstein in the development of his general theory of relativity.
Nowadays, experiments in this field have reached dimensions that can only be financed on the basis of globally organized media campaigns. As a result, the pressure to succeed in such experiments is also reaching previously unheard-of dimensions. This can lead, in particular, to a procedure of generating prefabricated "templates" before the actual measurements begin, as has become routine for example in the current search for gravitational waves. When further experiments then substantiate the suspicion that claimed gravitational wave signals originate from inside the experimental setups, this obviously does not affect the public acceptance of gravitational wave detection.
The high-speed rotor experiment proposed by James C. Keith in 1963 and its significance in view of Mach's principle (related section "Experimental Verification" meanwhile deleted from main article) had no chance of being recognised due to lack of public promotion. Jan Fremerey (talk) 10:14, 15 August 2022 (UTC)
thread_title:  On the significance of experimental verification 

message: Please would an interested editor assess the value of this addition which was made in the abandoned WP:COPYARTICLE (now blanked) User:Christillin/Mach e centrifuga in 2012: 
:Recently a semiquantitative realization of Mach's principle has been obtained, within the framework of an "effective" vector theory of gravitation, as regards both the Coriolis and the centrifugal force.
User:Christillin lists other user drafts which may likewise be worth checking. – Fayenatic London 14:50, 15 September 2022 (UTC)
thread_title:  Abandoned user draft