Lorentz, Hendrik Antoon

Lorentz, Hendrik Antoon (hĕn`drək än`tōn lō`rĕnts), 1853–1928, Dutch physicist, a pioneer in formulating the relations between electricity, magnetism, and light. He was one of the first to postulate the existence of electrons. On this he based his explanation of the Zeeman effect (a change in spectrum lines in a magnetic field), for which he shared with Pieter Zeeman the 1902 Nobel Prize in Physics. He extended the hypothesis of G. F. Fitzgerald, an Irish physicist, that the length of a body contracts as its speed increases (see Lorentz contraction), and he formulated the Lorentz transformation, by which space and time coordinates of one moving system can be correlated with the known space and time coordinates of any other system. This work influenced, and was confirmed by, Einstein's special theory of relativity. Lorentz also discovered (1880), simultaneously with L. V. Lorenz of the Univ. of Copenhagen, the relations (known as Lorentz-Lorenz relations) between the refraction of light and the density of a translucent body. He was professor (1878–1912) at the Univ. of Leiden and director from 1912 of the Teyler laboratory, Haarlem. His works in English include The Theory of Electrons (1909) and Problems of Modern Physics (1927).

Bibliography

See his collected papers (9 vol., 1934–39); study ed. by G. L. de Haas-Lorentz (tr. 1957).

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Lorentz, Hendrik Antoon

(born July 18, 1853, Arnhem, Neth.—died Feb. 4, 1928, Haarlem) Dutch physicist. He taught at the University of Leiden (1878–1912) and later directed Haarlem's Teyler Institute. In 1875 he refined James Clerk Maxwell's theory of electromagnetic radiation so that it explained the reflection and refraction of light. Aiming to devise a single theory to explain the relationship of electricity, magnetism, and light, he later suggested that atoms might consist of charged particles that oscillate and produce light. In 1896 his student Pieter Zeeman (1865–1943) demonstrated this phenomenon (see Zeeman effect), and in 1902 the two men were awarded the second Nobel Prize for Physics. In 1904 Lorentz developed the Lorentz transformations (including the so-called Fitzgerald-Lorentz contraction), mathematical formulas that relate space and time measurements of one observer to those of a second observer moving relative to the first. These formed the basis of Albert Einstein's special theory of relativity.