Joseph Larmor

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Sir Joseph Larmor (July 11, 1857 - May 19, 1942), an Irish physicist, mathematician and politician, researched electricity, dynamics, and thermodynamics.

Contents 1 Biography 2 Awards and honors 3 Publications 4 See also 5 External links and references

[edit] Biography

Larmor published the Lorentz transformations in the Philosophical Transactions of the Royal Society in 1897 (see Macrossan (1986)), some two years before Hendrik Lorentz (1899, 1904) and eight years before Albert Einstein (1905). Larmor predicted the phenomenon of time dilation, at least for orbiting electrons, and verified that the FitzGerald-Lorentz contraction (length contraction) should occur for bodies whose atoms where held together by electro-magnetic forces. In his book Aether and Matter (1900), he again presented the Lorentz transformations, time dilation and length contraction (treating these as dynamic rather than kinematic effects). Larmor was in opposition to Albert Einstein's theory of relativity (though he supported it for a short time). Larmor rejected both the curvature of space and the special theory of relativity, to the extent that he claimed that an absolute time was essential to astronomy (Larmor 1924, 1927).

Larmor proposed that the aether could be represented as a homogeneous fluid medium which was perfectly incompressible and elastic. Larmor believed the aether was separate from matter. Larmor united Lord Kelvin's model of spinning gyrostats (e.g., vortexes) with this theory.

Larmor held that matter consisted of particles moving in the aether. Larmor believed the source of electric charge was a "particle" (which as early as 1897 he was referring to as the electron). Thus, in what was apparently the first specific prediction of time dilation, he wrote "... individual electrons describe corresponding parts of their orbits in times shorter for the [rest] system in the ratio (1 - v²/c²)^1/2" (Larmor 1897).

Larmor held that the flow of charged particles constitutes the current of conduction (but was not part of the atom). Larmor calculated the rate of energy radiation from an accelerating electron. Larmor explained the splitting of the spectral lines in a magnetic field by the oscillation of electrons.

In February 1911 Joseph Larmor was elected as the Unionist MP for Cambridge University and remained in Parliament until the 1922 general election.

In 1919, Larmor proposed sunspots are self-regenerative dynamo action on the Sun's surface.

[edit] Awards and honors

1898 -- Adams Prize (Cambridge)

1914 -- De Morgan Medal (London Mathematical Society)

1915 -- Royal Medal (Royal Society)

1921 -- Copley Medal (Royal Society)

The Crater Larmor on the moon was named in his honour.

[edit] Publications

Larmor edited the complete works of George Stokes and William Thomson, 1st Baron Kelvin. Larmor wrote the obituaries of George Stokes, Josiah Gibbs, and William Thomson. Larmor's publications include:

• 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 papers containing Larmor's physical theory of the universe. The last, containing the Lorentz transformations, is 1897 (190): 205-300.
• 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.
• 1898, "Note on the complete scheme of electrodymnamic 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. (renamed by Horace Lamb Aether and no matter).
• 1903, "On the electrodymanic and thermal relations of energy of magnetisation," 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, "Newtonion time essential to astronomy," Nature.
• 1929, "Mathematical and Physical Papers. Cambridge Univ. Press.

[edit] See also

• George Gabriel Stokes
• Larmor precession
• Larmor frequency
• Larmor radius
• Larmor's Theorem
• Larmor's Formula
• Lucasian professor
• Relativity of simultaneity

[edit] External links and references

• Einstein, A. (1905) "Zur Elektrodynamik bewegter Körper", Annalen der Physik, 17, 891. English translation: On the electrodynamics of moving bodies
• Greco, Diane, "Ether and field theories". Massachusetts Institute of Technology.
• 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. "A note on relativity before Einstein", British Journal for the Philosophy of Science, 37 (1986): 232-234.
• Warwick, Andrew, "On the Role of the FitzGerald-Lorentz Contraction Hypothesis in the Development of Joseph Larmor's Electronic Theory of Matter". Archive for History of Exact Sciences 43 (1991): 29-91.
• Weisstein, Eric W., "Larmor, Joseph (1857-1942)". Science World.
• "Larmor, Sir Joseph (1857-1942)". AIM25.
• "Sir Joseph Larmor". Rug.ac.be.
• "Sir Joseph Larmor". School of Mathematics and Statistics, University of St Andrews, Scotland.
• "Joseph Larmor". University Science.
• "Papers of Sir Joseph Larmor". Janus, University of Cambridge.

Preceded by Sir George Stokes

Lucasian Professor at Cambridge University 1903–1932

Succeeded by Paul Dirac