Joseph Larmor

Sir Joseph Larmor, around 1920

Sir Joseph Larmor (born July 11, 1857 in Magheragall , County Antrim , Northern Ireland , † May 19, 1942 in Holywood , County Down ) was an Irish physicist and mathematician .

Life

Larmor studied at the Royal Belfast Academical Institution and Queens College in Belfast and then at Cambridge University at St. Johns College . He was then Professor of Theoretical Physics (called Natural Philosophy ) at Queens College Galway for five years .

From 1903 to 1932 he was a professor at the Luca-fish chair of mathematics at Trinity College of the University of Cambridge ; his predecessor in this position was George Gabriel Stokes , he was succeeded by Paul Dirac .

Larmor, who already spent the summer holidays regularly in his Irish homeland, retired to Holywood in Ireland. He never married. From 1911 to 1922 he was a member of the British Parliament for Cambridge University, where he spoke out in favor of maintaining the union between Ireland and Great Britain.

Larmor was one of the leading theoretical physicists in Britain in his day. He edited the collected works of Stokes, George Francis FitzGerald , John Henry Poynting , Henry Cavendish (1921) and William Thomson (Lord Kelvin), as well as the book Matter and Motion by James Clerk Maxwell .

plant

Larmor was the first to publish the Lorentz Transformation in 1897 , two years before Hendrik Antoon Lorentz and eight years before Albert Einstein . He predicted the effect of time dilation and confirmed the FitzGerald-Lorentz contraction , provided the molecules are held together by electromagnetic forces. In 1900 he presented the transformations in a somewhat clearer form, although like Lorentz, but in contrast to Einstein, he understood the associated effects as dynamic and not kinematic. Although he endorsed the theory of relativity for a short time, he later rejected it because he rejected space-time curvature and believed that absolute time was essential to astronomy.

Larmor assumed that ether can be imagined as a homogeneous, fluid medium that is incompressible and elastic. Like Lorentz, he believed that the movement of ether and matter should be strictly separated from one another. Larmor combined Kelvin's vortex aether model with his theory. Like Lorentz, he described matter as a flow of particles or electrons . Larmor assumed that matter or electrons have no substance of their own and are only a special form of ether.

After William Mitchinson Hicks' criticism of the Michelson-Morley experiment , which Larmor saw as confirmation of his theory of length contraction, Larmor looked for an alternative confirmation and thus stimulated the Trouton-Noble experiment by Frederick Thomas Trouton (and a planned review before that by Trouton's teacher George Francis FitzGerald , who died soon afterwards ).

Larmor is still known today for the Larmor frequency , the Larmor radius and a formula for the (non-relativistic) rate of energy radiation of an accelerated electron ( Larmor formula ).

Awards

In 1880 Larmor was in the Tripos examinations of the Senior Wrangler (first of the exams) of the University of Cambridge, which awarded him the Smith Prize in the same year ; In 1898 she awarded him the Adams Prize for his work Aether and Matter (from which his book of the same name emerged). In 1892 he was elected as a member (" Fellow ") in the Royal Society , which awarded him the Royal Medal in 1915 and the Copley Medal in 1921 . In 1903 he was elected to the American Academy of Arts and Sciences , in 1908 to the National Academy of Sciences , in 1909 he was promoted to a Knight Bachelor's degree . In 1910 he became an Honorary Fellow of the Royal Society of Edinburgh . The London Mathematical Society awarded him the De Morgan Medal in 1914 . In 1911 he became a foreign member of the Accademia Nazionale dei Lincei in Rome and in 1920 a corresponding member of the Académie des Sciences in Paris. In 1912 he gave a plenary lecture at the International Congress of Mathematicians in Cambridge (On the Dynamics of Radiation) and also in Strasbourg in 1920 (Questions in physical indetermination). The lunar crater Larmor was named after him.

See also

• History of the Lorentz Transformation
• History of the special theory of relativity
• Lorentz's theory of ethers

Publications

Larmor edited the collected works of George Gabriel Stokes and Lord Kelvin and wrote obituaries on Stokes, Kelvin and Josiah Gibbs .

• 1887, "On the direct applications of first principles in the theory of partial differential equations," Proceedings of the Royal Society .
• 1891, "On the theory of electrodynamics," Proceedings of the Royal Society .
• 1892, "On the theory of electrodynamics, as affected by the nature of the mechanical stresses in excited dielectrics," Proceedings of the Royal Society .
• 1893-97, "Dynamical Theory of the Electric and Luminiferous Medium," Proceedings of the Royal Society; Philosophical Transactions of the Royal Society . Series of 3 articles with Larmor's physical theory of space.
• 1894, "Least action as the fundamental formulation in dynamics and physics", Proceedings of the London Mathematical Society .
• 1896, "The influence of a magnetic field on radiation frequency", Proceedings of the Royal Society .
• 1896, "On the absolute minimum of optical deviation by a prism," Proceedings of the Cambridge Philosophical Society .
• 1897, " On a Dynamical Theory of the Electric and Luminiferous Medium, Part 3, Relations with Material Media, " Phil. Trans. Roy. Soc., Vol. 190, pp. 205-300. Contains the Lorentz transformation on p. 229.
• 1898, "Note on the complete scheme of electrodynamic equations of a moving material medium, and electrostriction", Proceedings of the Royal Society .
• 1898, "On the origin of magneto-optic rotation", Proceedings of the Cambridge Philosophical Society .
• 1900, " Aether and Matter, " Cambridge University Press. Also contains the Lorentz transformation.
• 1903, "On the electrodynamic and thermal relations of energy of magnetization," Proceedings of the Royal Society .
• 1907, “ Aether ” in Encyclopædia Britannica , 11th ed. London.
• 1908, “William Thomson, Baron Kelvin of Largs. 1824-1907 ”(Obituary). Proceedings of the Royal Society .
• 1924, "On Editing Newton," Nature .
• 1927, "Newtonian time essential to astronomy," Nature .
• 1929, "Mathematical and Physical Papers". Cambridge Univ. Press. Two volumes.

Individual evidence

1. ^ J. Larmor: On a Dynamical Theory of the Electric and Luminiferous Medium, Part 3, Relations with material media . In: Phil. Trans. Roy. Soc . tape 190 , 1897, pp. 205-300 .
2. ↑ J. Larmor: Aether and Matter . Cambridge University Press, 1900.
3. ↑ Andrew Warwick: The sturdy protestants of science: Larmor, Trouton and the earth's motion through the ether, in: Jed Z. Buchwald (ed.), Scientific Practice, University of Chicago Press 1995, pp. 300-344
4. ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. (PDF file) Royal Society of Edinburgh, accessed December 30, 2019 . 

Secondary sources

• MN Macrossan: A Note on Relativity Before Einstein . In: Brit. J. Phil. Sci . tape 37 , 1986, pp. 232-234 .
• Andrew Warwick: On the Role of the FitzGerald-Lorentz Contraction Hypothesis in the Development of Joseph Larmor's Electronic Theory of Matter . In: Archive for History of Exact Sciences. Volume 43, 1991, pp. 29-91.
• O. Darrigol: The Electron Theories of Larmor and Lorentz: A Comparative Study . In: Historical Studies in the Physical and Biological Sciences . tape 24 , 1994, pp. 265-336 .

Web links

Wikisource: Joseph Larmor  - Sources and full texts (English)

Commons : Joseph Larmor  - Collection of Images, Videos and Audio Files

• John J. O'Connor, Edmund F. Robertson :  Joseph Larmor. In: MacTutor History of Mathematics archive .
• A very short biography of Joseph Larmor ( Memento from July 19, 2009 in the Internet Archive )
• Ether and field theories in the late 19th century At VictorianWeb: History of science in the Victorian era
• Papers of Sir Joseph Larmor . Janus, University of Cambridge.