THE

LORENTZ-

FITZGERALD

CONTRACTION

MYTH

(1889–1892)

The Lorentz-FitzGerald Contraction Myth (1889–1892): The Desperate Attempt to Uphold Heliocentrism in the Wake of the 1887 Michelson-Morley Experiment

To counter the definitive, empirically-based refutation of heliocentrism implied by the 1887 Michelson-Morley paper1 — see Heliocentrism Refuted: The Michelson-Morely Experiment (1887), George Francis FitzGerald proposed (within two years) the absurd notion that the length of material bodies could actually contract due to their motion. In his 1889 note to Science, FitzGerald states:

   I have read with much interest Messrs. Michelson and Morley’s wonderfully delicate experiment attempting to decide the important question as to how far the ether is carried along by the earth. Their result seems opposed to other experiments showing that the ether in the air can be carried along only to an inappreciable extent. I would suggest that almost the only hypothesis that can reconcile this opposition is that the length of material bodies changes, according as they are moving through the ether or across it, by an amount depending on the square of the ratio of their velocity to that of light. We know that electric forces are affected by the motion of the electrified bodies relative to the ether, and it seems a not improbable supposition that the molecular forces are affected by the motion, and that the size of a body alters consequently. It would be very important if secular experiments on electrical attractions between permanently electrified bodies, such as in a very delicate quadrant electrometer, were instituted in some of the equatorial parts of the earth, to observe whether there is any diurnal and annual variation of attraction, — diurnal due to the rotation of the earth being added and subtracted from its orbital velocity; and annual similarly for its orbital velocity and the motion of the solar system.2

This absurdity was further developed a few years later by Hendrik Antoon Lorentz in his 1892 paper.3 The relevant points from that paper are as follows (in Dutch followed by English):

   […]

   Maxwell had reeds opgemerkt dat, indien de aether niet medegaat, de beweging der aarde een invloed moet hebben op den tijd dien het licht behoeft om tusschen twee vaste met de aarde verbonden punten heen en weer te gaan. Is \(l\) de afstand, \(V\) de snelheid van het licht, en \(p\) die der aarde, dan is de bedoelde tijd als de verbindingslijn der punten evenwijdig loopt aan de bewegingsrichting der aarde \[2 \frac{l}{V}\left(1+\frac{p^2}{V^2}\right)\tag{1}\]

en als zij loodrecht daarop staat\[2 \frac{l}{V}\left(1+\frac{p^2}{2V^2}\right),\tag{2}\]

gevende een verschil \[\frac{lp^2}{V^3}.\tag{3}\]4 [...]

   Ik heb lang vruchteloos over deze proef [Michelson en Morley] nagedacht en heb ten slotte slechts één middel kunnen bedenken om de uitkomst ervan met de theorie van Fresnel te verzoenen. Het bestaat in de onderstelling dat de verbindingslijn van twee punten van een vast lichaam niet even lang blijft indien zij eerst evenwijdig aan de bewegingsrichting der aarde loopt en vervolgens loodrecht daarop wordt geplaatst. Indien b. v. de aftstand in ’t laatste gevel \(l\) en in ’t eerste \(l (1-α)\) is, moet men van de uitdukkingen \((1)\) en \((2)\) de eerst met \(1-α\) vermenigvuldigen. Met verwaarloozing van \(\frac{αp^2}{V^2}\) geeft dit \[2 \frac{l}{V}\left (1+\frac{p^2}{V^2}-α\right).\]

   Het verschil hiervan met \((2)\) — en daarmede ’t geheele bezwaar — zou verdwijnen als \[α=\frac{p^2}{2V^2}\]was.

   Eene dergelijke verandering van de lengte der armen bij de eerste proef van Michelson, en van de afmetingen van den steen bij de tweede is nu inderdaad, naar ’t mij voorkomt, niet ondenkbaar.5

   [...]

   Met dat al schijnt het niet te ontkennen dat veranderingen der molekulaire krachten, en dien ten gevolge der afmetingen van een lichaam, van de orde \(\frac{p^2}{2V^2}\) mogelijk zijn.6

   […]

In English:7

   Maxwell had already observed that if the ether is not dragged along, the motion of the earth must influence the time required by light to travel to and fro between two points rigidly fixed to the earth. Denoting their distance by \(l\), the velocity of light by \(V\), that of the earth by \(p\), the time in question is, when the line joining the points is parallel to the earth’s motion \[2 \frac{l}{V}\left(1+\frac{p^2}{V^2}\right)\tag{1},\]

and when at right angles to that direction \[2 \frac{l}{V}\left(1+\frac{p^2}{2V^2}\right)\tag{2},\]

giving a difference \[\frac{lp^2}{V^3}.\tag{3}\]8 [...]

   This [Michelson and Morley] experiment has been puzzling me for a long time, and in the end I have been able to think of only one means of reconciling its result with Fresnel’s theory. It consists in the supposition that the line joining two points of a solid body, if at first parallel to the direction of the earth’s motion, does not keep the same length when it is subsequently turned through \(90^\circ\). If, for example, its length be \(l\) in the latter position and \(l (1-α)\) in the former, the [expressions \((1)\) and \((2)\)] must be multiplied by \((1-α)\). Neglecting \(\frac{αp^2}{V^2}\) this gives \[2 \frac{l}{V}\left (1+\frac{p^2}{V^2}-α\right).\]

   The difference between this expression and \((2)\), and with it the whole difficulty, would disappear if \(α\) were equal to \(\frac{p^2}{2V^2}\).

   Now, some such change in the length of the arms in Michelson’s first experiment and in the dimensions of the slab in the second one is so far as I can see, not inconceivable.9

   […]

   […]

   But for all that, it seems undeniable that changes in the molecular forces and, consequently, in the dimensions of a body are possible of the order of \(\frac{p^2}{2V}\).10 […]

While such a possibility may have seemed undeniable to Lorentz, the fact of the matter is that length contraction has never been (nor never can be) experimentally demonstrated. It was a desperate but historically successful attempt to derail what was essentially a scientific breakthrough by Michelson and Morley and impede real scientific progress (at least in the public domain) for well over a century. Length contraction was a wild assumption that was eventually converted into a metaphysical precept by Einstein — see Einstein’s Special Theory of Relativity Myth (1905). It nevertheless remains inherently untestable and therefore outside the framework of the scientific method.


— FINIS —


  1. Albert A. Michelson and Edward W. Morley, “On the relative motion of the Earth and the Luminiferous Ether.” The American Journal of Science, Third Series, Vol. XXXIV, No. 203 (November 1887), Art. XXXVI, pp. 333–345.↩️

  2. George Francis FitzGerald, “The Ether and the Earth’s Atmosphere,” Science, Vol. XIII, No. 328 (May 17, 1889), p. 390.↩️

  3. Lorentz, Hendrik Antoon (1892), “De relatieve beweging van de aarde en den aether” [“The Relative Motion of the Earth and the Aether”], Zittingsverlag Akad. V. Wet., 1: 74–79.↩️

  4. Ibid., p. 75.↩️

  5. Ibid., p. 76.↩️

  6. Ibid., p. 78.↩️

  7. Hendrik Antoon Lorentz, “The relative motion of the earth and the ether,” in H.A. Lorentz, Collected Papers (Volume IV), edited by P. Zeeman and A.D. Fokker (The Hague, M. Nijhoff, 1937), pp. 219–223.↩️

  8. Ibid., pp. 219–220.↩️

  9. Ibid., p. 221.↩️

  10. Ibid., p. 223.↩️


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