FitzGerald, George Francis

▪ Irish physicist

born Aug. 3, 1851, Dublin

died Feb. 22, 1901, Dublin

      physicist who first suggested a method of producing radio waves, thus helping to lay the basis of wireless telegraphy. He also developed a theory, now known as the Lorentz–FitzGerald contraction (Lorentz-FitzGerald contraction), which Einstein used in his own special theory of relativity.

      FitzGerald became a tutor at Trinity College in Dublin in 1877 and professor of natural and experimental philosophy in 1881. From his studies of radiation he concluded that an oscillating electric current would produce electromagnetic waves. This finding was later verified experimentally by Heinrich R. Hertz of Germany and used in the development of wireless telegraphy.

      Independently of Hendrik A. Lorentz of The Netherlands, FitzGerald studied the results of the Michelson–Morley experiment (Michelson-Morley experiment) (1887) and arrived at a similar conclusion. The experiment was an attempt to measure the Earth's motion relative to the pervasive luminiferous ether postulated as the medium within which light waves were propagated. The attempt failed to detect any such motion. In 1892 FitzGerald suggested that when in motion, a body is shorter (along its line of motion) than when at rest and that such a shortening, or contraction, affects the instruments used in the experiment. Lorentz arrived at this idea independently in 1895 and developed it considerably. A collection, The Scientific Writings of the Late George Francis FitzGerald, was published in 1902.

* * *