Georges Sagnac

Georges Sagnac (* 1869, † 1926) was a French physicist. He is the namesake of the Sagnac effect, a phenomenon which is the basis of the Sagnac interferometer and thus the developed since the 1970s, laser gyro.

Life and work

Little is known about the life of Georges Sagnac, apart from the fact that he was one of the first researchers in France, which dealt with X-rays. He reached Wilhelm Conrad Roentgen on work while he was a laboratory technician at the Sorbonne.

From Marie Curie is narrated that the Curies was the time of the discovery of radioactivity in the exchange of ideas with Sagnac.

He belonged to a circle of friends and scientists, including the Pierre and Marie Curie, Paul Langevin, Jean Perrin, and the mathematician Émile Borel belonged.

In 1913 showed Georges Sagnac that when light is directed in two opposite directions on a closed path, which is on a rotating platform, there is a phase shift. The beam moves with the outer rotation comes to later than the oppositely running. The theory of this experiment was given in 1911 by Max von Laue, who calculated that according to both the theory of relativity as well as the stationary luminiferous ether, a positive result was to be expected only when completely entrained ether, this effect would not occur. Sagnac, however, mistakenly believed his experiment would prove only the airwaves and was subsequently an opponent of the theory of relativity.

Writings (selection )

  • Sur la transformation of the rayons X par les métaux. Comptes rendus, 125:230-231, 1897.
  • Émission de rayons secondaires par l'air sous l' influence of rayons X. Comptes rendus, 126:521, 1898.
  • Sur la transformation of the rayons X par les differents corps. Comptes rendus, 128:546-552, 1899.
  • Émission de differents rayons inégalement absorbables, dans la transformation of the rayons X par un même corps. Comptes rendus, 128:300-303, 1899.
  • De l' optique de rayons of the X-ray et des rayons secondaires qui en ... dérivent thesis, Faculté des Sciences de Paris, 1900. 380 no, no d'ordre 1050.
  • Électrisation négative of rayons secondaires produits au moyen of rayons X-ray. In: Comptes rendus hebdomadaires of séances de l' Académie des sciences. Volume 130, pp. 1013-1016, 1900; online - with Pierre Curie
  • L' éther lumineux démontré par l' effet du vent d' relatif éther dans un interféromètre en rotation uniforme. In: Comptes Rendus. Volume 157, pp. 708-710, 1913;
  • Sur la preuve de la réalité de l' éther lumineux par l' expérience de l' interférographe tournant. In: Comptes Rendus. Volume 157, pp. 1410-1413, 1913;
  • Physicist ( 20th century)
  • Frenchman
  • Born in 1869
  • Died in 1926
  • Man
  • University teachers ( University of Lille I)
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