Hendrik Antoon Lorentz (July 18, 1853 – February 4, 1928) was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect. He also derived the transformation equations subsequently used by Albert Einstein to describe space and time.
During the first twenty years in Leiden, Lorentz was primarily interested in the theory of electromagnetism to explain the relationship of electricity, magnetism, and light. After that, he extended his research to a much wider area while still focusing on theoretical physics. From his publications, it appears that Lorentz made contributions to mechanics, thermodynamics, hydrodynamics, kinetic theories, solid state theory, light, and propagation. His most important contributions were in the area of electromagnetism, the electron theory, and relativity.
Lorentz theorized that the atoms might consist of charged particles and suggested that the oscillations of these charged particles were the source of light. When colleague and former student of Lorentz Pieter Zeeman discovered the Zeeman effect in 1896, Lorentz supplied its theoretical interpretation. The experimental and theoretical work was honored with the Nobel prize in physics in 1902. Lorentz' name is now associated with the Lorentz-Lorenz formula, the Lorentz force, the Lorentzian distribution, and the Lorentz transformation.
In 1892, with the attempt to explain the Michelson-Morley experiment, Lorentz proposed that moving bodies contract in the direction of motion (see length contraction; George FitzGerald had already arrived at this conclusion, see FitzGerald-Lorentz Contraction). Lorentz worked on describing electromagnetic phenomena (the propagation of light) in reference frames that moved relative to each other. He discovered that the transition from one to another reference frame could be simplified by using a new time variable which he called local time. The local time depended on the universal time and the location under consideration. Lorentz's publications (of 1895 and 1899) made use of the term local time without giving a detailed interpretation of its physical relevance. In 1900, Henri Poincaré called Lorentz's local time a "wonderful invention" and illustrated it by showing that clocks in moving frames are synchronized by exchanging light signals that are assumed to travel at the same speed against and with the motion of the frame. In 1899, and again in 1904, Lorentz added time dilation to his transformations and published what Poincaré in 1905 named Lorentz transformations. It was apparently unknown to Lorentz that Joseph Larmor had used identical transformations to describe orbiting electrons in 1897. Larmor's and Lorentz's equations look somewhat unfamiliar, but they are algebraically equivalent to those presented by Poincaré and Einstein in 1905. Lorentz's 1904 paper includes the covariant formulation of electrodynamics, in which electrodynamic phenomena in different reference frames are described by identical equations with well defined transformation properties. The paper clearly recognizes the significance of this formulation, namely that the outcomes of electrodynamic experiments do not depend on the relative motion of the reference frame. The 1904 paper includes a detailed discussion of the increase of the inertial mass of rapidly moving objects. In 1905, Einstein would use many of the concepts, mathematical tools and results discussed to write his paper entitled "Elektrodynamik" (Electrodynamics) known today as the theory of special relativity. Because Lorentz laid the fundamentals for the work by Einstein, this theory was called the Lorentz-Einstein theory originally.
The increase of mass was the first prediction of special relativity to be tested, but from early experiments by Kaufmann it appeared that his prediction was wrong; this led Lorentz to the famous remark that he was "at the end of his Latin. The confirmation of his prediction had to wait until 1908. In 1909, Lorentz published "Theory of Electrons" based on a series of lectures in Mathematical Physics he gave at Columbia University.
Poincaré (1902) said of Lorentz's theory of electrodynamics:
Paul Langevin (1911) said of Lorentz:
Lorentz was chairman of the first Solvay Conference held in Brussels in the autumn of 1911. Shortly after the conference, Poincaré wrote an essay on quantum physics which gives an indication of Lorentz's status at the time:
Albert Einstein (1953) wrote of Lorentz:
In 1912 Lorentz retired early to become director of research at Teylers Museum in Haarlem, although he remained external professor at Leiden and gave weekly lectures there. Paul Ehrenfest succeeded him in his chair at the University of Leiden, founding the Institute for Theoretical Physics which would become known as the Lorentz Institute. In addition to the Nobel prize, Lorentz received a great many honours for his outstanding work. He was elected a Fellow of the Royal Society in 1905. The Society awarded him their Rumford Medal in 1908 and their Copley Medal in 1918.
While Lorentz is mostly known for fundamental theoretical work, he also had an interest in practical applications. In the years 1918-1926, at the request of the Dutch government, Lorentz headed a committee to calculate some of the effects of the proposed Afsluitdijk (Closure Dike) flood control dam on other seaworks in the Netherlands. Hydraulic engineering was mainly an empirical science at that time, but the disturbance of the tidal flow caused by the Afsluitdijk was so unprecedented that the empirical rules could not be trusted. Lorentz proposed to start from the basic hydrodynamic equations of motion and solve the problem numerically. This was feasible for a "human computer", because of the quasi-one-dimensional nature of the water flow in the Waddenzee. The Afsluitdijk was completed in 1933 and the predictions of Lorentz and his committee turned out to be remarkably accurate.
Richardson describes Lorentz as:
M. J. Klein (1967) wrote of Lorentz's reputation in the 1920s: