Background
Sagnac was born at Périgueux and entered the École Normale Supérieure in 1889.
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Georges Sagnac
Edit Profilephysicist university professor
Education
University of Paris; École Normale Supérieure.
Career
While a lab assistant at the Sorbonne, he was one of the first in France to study X-rays, following Wilhelm Conrad Röntgen. Sagnac died at Meudon-Bellevue. In 1913, Georges Sagnac showed that if a beam of light is split and sent in two opposite directions around a closed path on a revolving platform with mirrors on its perimeter, and then the beams are recombined, they will exhibit interference effects.
From this result Sagnac concluded that light propagates at a speed independent of the speed of the source.
The motion of the earth through space had no apparent effect on the speed of the light beam, no matter how the platform was turned. The effect had been observed earlier (by Harress in 1911), but Sagnac was the first to correctly identify the cause.
This (in vacuum) was theoretically predicted by Max von Laue already in 1911. He showed that such an effect is consistent with stationary ether theories (such as the Lorentz ether theory) as well as with Einstein"s theory of relativity.
lieutenant is generally taken to be inconsistent with a complete ether drag.
And also inconsistent with emission theories of light, according to which the speed of light depends on the speed of the source.
Connections
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Born
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Died
February 26, 1928 (aged 58) -
Nationality
France