Friday, April 14, 2017

Poincare discovered relativistic gravity

Marco Mamone-capria ·writes in a new paper:
Looking back at the origins of the relativity revolution, it is interesting to note that the main reason given at the Saint-Louis conference of 24 September 1904 by Poincare for hesitating at a full endorsement of the principle of relativity was that celestial mechanics had suggested that the speed of the gravitational interaction exceeded that of light by at least six orders of magnitude ([45], p. 312, [46], p. 134; cit. in [37], pp.779-80).

A few months later Poincare changed his mind, if tentatively, when he discovered what, in our terms, are the first Poincare-invariant formulations of gravitation. He announced and, respectively, described in detail these findings (among many others) in his two famous articles of 1905 and 1906 ([47], [48]). Historians of physics have often taxed Poincare with not being bold enough to espouse the new theory of relativity in the trenchant way adopted a few weeks later by a young patent office clerk, who nonchalantly disposed of the aether as “superfluous”.27

At an historical distance of more than a century Poincare’s hesitancy is worth our admiration for its methodological wisdom.
This is correct. Poincare was many years ahead of Einstein in relativistic analysis of gravitation and causality.

Yes, some authors are impressed by Einstein calling the aether superfluous, but he was just echoing what Poincare had been saying for many years. As early as 1889, Poincare predicted that “the day will doubtless come when the ether will be rejected as useless”. He repeated this in his widely-read 1902 book.

Capria has a lot of excellent detail on the history of special relativity in his 2011 paper. I had not seen this early, and it partially explains the bias against Poincare.


  1. When you say Poincare discovered relativistic gravity, you should probably note that Poincare's proposed theory turned out to be wrong, e.g., it didn't satisfy the equivalence principle, it didn't correctly account for mass-energy equivalence, it gave wrong predictions for orbital precession, light deflection, etc. Also, Poincare was neither the first nor the last to propose a (wrong) relativistic theory of gravitation. The first (and so far the only) successful relativistic theory of gravity is general relativity, developed by Albert Einstein.

  2. One could just as easily say that Einstein's theory was wrong, because it did not correctly account for dark energy. Or that Heisenberg's theory of quantum mechanics was also wrong, for some shortcoming of the theory.

    Poincare's theory did correctly account for Lorentz transformations, and the finite propagation speed of gravitational fields. It was a crucial step in the development of relativistic gravity, and all subsequent work depended on it. It is very strange that all the articles about the recently LIGO detection of gravity waves always mention Einstein, and not Poincare. Gravity waves were Poincare's idea, not Einstein's.

    1. Poincare's 1905/6 paper was certainly admirable for many reasons, but, as Poincare himself admits, Lorentz's theory already furnishes us with examples that show any relativistic field theory must have components, analogous to the magnetic field for electromagnetism, that cancel the aberration effect, so Laplace's argument doesn't apply. It's the same reason there was no torque in the Trouton-Noble experiment, as explained in Lorentz's 1904. So, Poincare was not the originator of this insight about relativistic theories. More importantly, Poincare had no field equations for gravitation, and certainly didn't work out any equations for gravitational waves. And his whole approach, staying within the context of special relativity, was incapable of leading to the correct field equations. Einstein was the first to develop the field equations that are the basis for all the binary pulsar and now the LIGO calculations, etc. So it's surely understandable that his name is associated with the modern theory of gravitational waves. Also, I think it's inaccurate to imply (without actually saying) that subsequent work depended on Poincare, because his Palermo paper was neglected, and was regarded mostly as an exposition, with some amplifications, of Lorentz's theory. The part on gravitation, though interesting, it was a theoretical dead end.

  3. Poincare's Palermo paper was not neglected. It was absolutely crucial for Minkowski's papers, and Minkowski's work was essential for subsequent progress by Einstein and others.

    On the other hand, Einstein's 1905 paper was hardly used at all in that line of research, and had much less impact at the time.

    Poincare did explicitly refute Laplace's argument, and argue for gravitational waves. Maybe Lorentz would have gotten there, but he did not say so, as far as I know, and Einstein did not either until many years after Poincare.

    As for Einstein being the first to write down the field equations used in binary pulsar and LIGO calculations, I am not sure that is true either. I think that Grossmann was the first to say that empty spacetime was Ricci-flat in 1913.

    Einstein didn't exactly do much with gravitational waves either, as I think he even wrote a paper claiming that they do not exist.

  4. Minkowski's work was not based on Poincare. (The Palermo paper was in an obscure venue.) It's true that Poincare anticipated Minkowski in several things, but that is different than saying Minkowski's work was based on Poincare. Again, the absence of first-order aberration in relativistic forces was already a known feature of Lorentz's theory, as Poincare noted. As to your suggestion that Grossman be credited with the Einstein field equations, I would direct you to their joint paper, in which Grossman always refers to "Einstein's theory of gravitation", and distanced himself from the physical part of the paper. Grossman's contribution doesn't contain any physics. Einstein was the first to give the quadrupole solution (1918), which is the foundation of all subsequent work. The fact that he entertained (for a short time) doubts about possible realistic sources is irrelevant. Even before 1900 Lorentz wrote about gravity propagating at c, as had other before that. But Einstein created the modern subject of gravitational waves.

  5. The Palermo paper was not that obscure. All the major libraries had it. Minkowski had a copy of it, and studied it intensely. We know this because Minkowski made reference to it, even if to cheat Poincare of credit. For example, the 2011 paper mentioned above says:
    "What is quite clear is that Minkowski was overanxious to earn a decisive place in the historical development of the theory, and that to this end he did not care to give even such an eminent foreign colleague as Poincare, whose work he followed with the utmost attention,45 blatantly less than his due.46"

    Yes, Minkowski's work was most emphatically based on Poincare, and not Einstein.

    Maybe Lorentz should also get some credit for originating the idea of gravitational waves.

    Grossmann's contribution was Ricci=0. Hilbert had an equivalent way of saying the same thing. Yes, that is a mathematical equation, but that is what you said was so important. If so, Einstein depended on Grossmann and Hilbert for getting this.

  6. In his Cologne address Minkowski cited only Lorentz and Einstein, and even in other venues when he mentioned Poincare it only as the one who named the Lorentz transformations. Minkowski claimed originality for his works, and it isn't particularly implausible, since any competent mathematician would notice that the Lorentz transformation leaves invariant the quantity x^2 + y^2 + z^2 - c^2t^2. This is already tantamount to recognizing the Lorentz transformations are (hyperbolic) rotations in 4D space-time. The "great man" theory of history, according to which only a single person can have thought of something is often untrue. You think Poincare was the original source of wisdom, without whom Minkowski could not have done his work, but that is doubtful. In any case, this is all irrelevant to the point, which is that the modern theory of gravitation is Einstein's general relativity, and the associated modern theory of gravitational waves was founded by Einstein, particularly his 1918 paper giving the quadrupole solution. It is very ahistorical to credit the modern theory of gravitational waves (let alone general relativity) to Lorentz, Poincare, or Minkowski.

    1. This troll was addressed before with citations. You won't admit Minkowski cites Poincare. Crank.

      It was Einstein who falsely credited Minkowski for showing Lorentz transformations are rotations in spacetime, whereas it was Poincare in 1906.

      "Einstein's general relativity"


    2. "Minkowski was certainly aware of Poincar ́e’s paper Sur la dynamique de l’ ́electron published
      in 1906 (but received by Rendiconti del Circolo matematico Rendiconti del Circolo di Palermo on July 23, 1905) since he quoted it in his previous lectures given in November and December 1907."

      Why didn't he cite it in the Cologne lecture
      Space and Time? It's obvious! HE DIDN'T DO IT FIRST. An egotistical dick like most overrated academics that invent nothing revolutionary or practical.

      "In the absence of any clear indication why Minkowski left Poincare out of his lecture, a speculation or two on his motivation may be entertained. If Minkowski had chosen to include some mention of Poincar ́e’s work, his own contribution may have appeared derivative. Also, Poincare’s modification of Lorentz’s theory of electrons constituted yet another example of the cooperative role played by the mathematician in the elaboration of physical theory. Poincare’s “more mathematical” study of Lorentz’s electron theory demonstrated the mathematician’s dependence upon the insights of the theoretical physicist, and as such, it did little to establish the independence of the physical and mathematical paths to the Lorentz group."

  7. Yes, Minkowski cites Poincare only for naming the Lorentz transformations. What does that tell you? It tells me that Minkowski read Poincare's papers, but only credited him for a triviality. Minkowski was trying to get all the credit for himself.

    Minkowski's famous paper starts "The concepts about time and space", but he never mentions that those concepts are straight out of Poincare's paper. Even if Minkowski independently rediscovered those concepts, he was dishonest to not cite Poincare.

    I am not the one with the "great man" theory. You (Anonymous) and others who say "Einstein's general relativity" are subscribing to the great man theory. General relativity resulted from the work of several scholars. I posted a good account of the history here.

  8. I'm not here to analyze Minkowski's behavior or motivations vis-à-vis Poincare. Creative people are often not receptive to, or appreciative of, the competing works of others. I stipulated that Poincare anticipated Minkowski in several things for which Minkowski is commonly credited. But this is far removed from the subject at hand, which is your blog claim that Poincare should be credited as the discoverer of the theory of gravitational waves as supported by (for example) the LIGO observations. My comment is that the ideas for a relativistic theory of gravity outlined by Poincare in his 1905/6 paper are not the ideas that led to the theory of gravitational waves confirmed by the LIGO observations. The originator of the modern theory of gravity and gravitational waves was Einstein. It's well known that one of the tools that Einstein used was the 4D formalism of special relativity highlighted by Minkowski, which Minkowski claimed to have conceived of independently, but which may or may not have been influenced by his reading of Poincare, and was certainly by his own account influenced by his (Minkowski's) reading of Lorentz and Einstein. This was just one of many ingredients that Einstein exploited to create the modern theory of gravity, and hence gravitational waves.