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Astro*Dictionary by Michael Erlewine





1 article for "Fizeau, Armand Hippolyte Louis"

Fizeau, Armand Hippolyte Louis [Astro*Index]

(fee-zoh') (1819-1896) French physicist.

Born at Paris; died at Venteuil, Seine-et- Marne). In 1849, he used a rapidly turning toothed disk and a fixed mirror on hilltops, separated by 5 miles, to measure the velocity of light. This procedure was improved by Foucault. In 1848, Fizeau also (correctly) theorized that spectral lines from a source which moved with respect to the observer should be shifted from their rest positions; toward the violet, if the source is approaching, and toward the red, if receding. This effect, now called the Doppler Effect, was not actually measured for another 20 years.

See also:
♦ Foucault, Jean Bernard Leon ♦ Light, Velocity of ♦ Light Spectrum


Astro*Index Copyright © 1997 Michael Erlewine