Hendrik Lorentz

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Hendrik Antoon Lorentz (July 18, 1853, Arnhem – February 4, 1928, Haarlem) was a Dutch physicist and the winner of the 1902 Nobel Prize in Physics for his work on electromagnetic radiation.

Lorentz attended primary school in Arnhem until he was 13 years of age when he entered the new High School there. He entered the University of Leiden in 1870 but, in 1872, he returned to Arnhem to take up teaching evening classes. He worked for his doctorate while holding the teaching post.

In his doctoral thesis for University of Leiden (1875), Lorentz refined the electromagnetic theory of James Clerk Maxwell to better explain the reflection and refraction of light. His name is now associated with the Lorentz-Lorenz formula, the Lorentz force, the Lorentzian distribution, and the Lorentz transformation. He was appointed professor of theoretical physics at the University of Leiden in 1878. During his time there he was primarily interested in a single theory to explain the relationship of electricity, magnetism, and light. Lorentz theorized that the atoms might consist of charged particles and suggested that the oscillations of these charged particles were the source of light. This was experimentally proven in 1896 by Pieter Zeeman, a colleague and former student of Lorentz.

1 Achievements in electrodynamics and "Relativity"
2 Later life
3 See also
4 References

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Achievements in electrodynamics and "Relativity"

In 1895 in an 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). He introduced the term local time which expresses the relativity of simultaneity between reference frames in relative motion. Henri Poincaré in 1900 called Lorentz's local time a "wonderful invention" and showed how it arose when clocks in moving frames are sychronized by exchanging light signals which are assumed to travel with 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 the Lorentz transformations. It was apparently unknown to Lorentz that Joseph Larmor had predicted time dilation, at least for orbiting electrons, and published the identical transformations in 1897. Larmor's and Lorentz's equations look unfamilar, but are algebraically equivalent to those presented by Poincaré and Einstein in 1905 (see Macrossan (1986)). These mathematical formulas describe basic effects of the theory of Special relativity, namely the increase of mass, shortening of length, and time dilation that are characteristic of a moving body, all of which Lorentz had discussed in his 1899 publication. Image:Einstein en Lorentz.jpg Mass increase 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."[1] Its confirmation had to wait until 1908.

Poincaré (1902) said of Lorentz's theory of electrodynamics

The most satisfactory theory is that of Lorentz; it is unquestionably the theory that best explains the known facts, the one that throws into relief the greatest number of known relations ... it is due to Lorentz that the results of Fizeau on the optics of moving bodies, the laws of normal and abnormal dispersion and of absorption are connected with each other ... Look at the ease with which the new Zeeman phenomenon found its place, and even aided the classification of Faraday's magnetic rotation, which had defied all Maxwell's efforts. (Poincaré 1902)

Paul Langevin (1911) said of Lorentz

It is the great merit of H. A. Lorentz to have seen that the fundamental equations of electromagnetism admit a group of transformations which enables them to have the same form when one passes from one frame of reference to another; this new transformation has the most profound implications for the transformations of space and time

which nowadays could easily be mistaken for a reference to Einstein. Lorentz was chairman of the first Solvay Conference held in Brussels in the autumn of 1911. Shorty after the conference, Poincaré wrote an essay on quantum physics which gives an indication of Lorentz's status at the time:

... at every moment [the twenty physicists from different countries] could be heard talking of the [quantum mechanics] which they contrasted with the old mechanics. Now what was the old mechanics? Was it that of Newton, the one which still reigned uncontested at the close of the nineteenth centrury? No, it was the mechanics of Lorentz, the one dealing with the principle of relativity; the one which, hardly five years ago, seemed to be the height of boldness. (Poincaré 1913)

In the same essay Poincaré lists the enduring aspects of Lorentzian mechanics:

no body in motion will ever be able to exceed the speed of light ... the mass of a body is not constant ... no experiment will ever be able [to detect] motion either in relation to absolute space or even in relation to the ether. (Poincaré 1913)

Thus Dingle remarked:

Until the first World War, Lorentz's and Einstein's theories were regarded as different forms of the same idea, but Lorentz, having priority and being a more established figure speaking a more familiar language, was credited with it (Dingle 1967, Nature 216 p.119-122)

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Later life

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.

The respect that Lorentz held in the Netherlands is seen in O. W. Richardson's description of his funeral [6]:

The funeral took place at Haarlem at noon on Friday, February 10. At the stroke of twelve the State telegraph and telephone services of Holland were suspended for three minutes as a revered tribute to the greatest man Holland has produced in our time. It was attended by many colleagues and distinguished physicists from foreign countries. The President, Sir Ernest Rutherford, represented the Royal Society and made an appreciative oration by the graveside.

Richardson describes Lorentz as:

[A] man of remarkable intellectual powers ... . Although steeped in his own investigation of the moment, he always seemed to have in his immediate grasp its ramifications into every corner of the universe. ... The singular clearness of his writings provides a striking reflection of his wonderful powers in this respect. .... He possessed and successfully employed the mental vivacity which is necessary to follow the interplay of discussion, the insight which is required to extract those statements which illuminate the real difficulties, and the wisdom to lead the discussion among fruitful channels, and he did this so skillfully taught the process was hardly perceptible.

M. J. Klein (1967) wrote of Lorentz's reputation in the 1920s: For many years physicists had always been eager "to hear what Lorentz will say about it" when a new theory was advanced, and, even at seventy-two, he did not disappoint them.

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References

Klein, M. J. (1967) "Letters of wave mechanics: Schrödinger, Planck, Einstein, Lorentz" (ed. K. Przibram), Philosophical Library, New York.
Langevin, P. (1911) "L'évolution de l'éspace et du temps", Scientia, X, 31-54
Larmor, J. (1897) "On a dynamical theory of the electric and luminiferous medium", Phil. Trans. Roy. Soc. 190, 205-300 (third and last in a series of papers with the same name).
Lorentz, H. A. Versuch Einer Theorie der Elektrischen und Optischen Erscheinungen in Bewegten Körpern, Leiden (book). ("Towards a theory of electrical and optical phenomena of moving bodies")
Lorentz, H. A. (1899) "Simplified theory of electrical and optical phnomena in moving systems", Proc. Acad. Science Amsterdam, I, 427-43.
Lorentz, H. A. (1904) /"Electromagnetic phenomena in a system moving with any velocity less than that of light", Proc. Acad. Science Amsterdam, IV, 669-78.
Macrossan, M. N. (1986) "A note on relativity before Einstein", Brit. J. Phil. Sci., 37, 232-234
Poincaré, H. (1900) "La théorie de Lorentz et le Principe de Réaction", Archives Neerlandaises, V, 253-78.
Poincaré, H. (1902) La Science et L'Hypothèse. Quote from the English translation Science and Hypothesis, Walter Scott (1905) as republished unabrodged by Dover 1952, p. 175.
Poincaré, H. (1905) "Sur la dynamique de l'électron", Comptes Rendues, 140, 1504-8.
Poincaré, H. (1913) Dernières Pensées Ernest Flammarion 1913. Quote from English translation: Mathematics and Science: Last Essays, Dover 1963.
Template:MacTutor Biography
Biography at brainparad.com
Lorentz and the Zuiderzee project

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Categories: 1853 births | 1928 deaths | Dutch physicists | Nobel Prize in Physics winners | Dutch Nobel Prize winners

Hendrik Lorentz

From Free net encyclopedia

Contents

Achievements in electrodynamics and "Relativity"

Later life

See also

References

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