Sir Joseph Larmor (11 July 1857 â 19 May 1942) was an Irish mathematician, theoretical physicist, and British politician who made breakthroughs in the understanding of electricity, dynamics, thermodynamics, and the electron theory of matter. His most influential work was Aether and Matter, a theoretical physics book published in 1900.
Joseph Larmor was born on 11 July 1857 in Magheragall, County Antrim, the son of Hugh Larmor, a Belfast shopkeeper and his wife, Anna Wright. The family moved back to Belfast, where he was educated at the Royal Belfast Academical Institution, and then studied mathematics and experimental science at Queen's College, Belfast (B.A., 1874; M.A., 1875), where one of his teachers was John Purser. He subsequently studied at St John's College, Cambridge, where in 1880 he was Senior Wrangler (J. J. Thomson was second wrangler that year) and Smith's Prizeman, getting his M.A. in 1883.
After teaching physics for five years at Queen's College, Galway, Larmor accepted a lectureship in mathematics at Cambridge in 1885. In 1903, he was appointed Lucasian Professor of Mathematics, a position he held until his retirement in 1932. He never married. He was knighted by King Edward VII in 1909.
Motivated by his strong opposition to Home Rule for Ireland, in February 1911 Larmor ran for and was elected a Member of Parliament for Cambridge University with the Conservative party. He remained in parliament until the 1922 general election, at which point the Irish question had been settled. Upon his retirement from Cambridge in 1932, Larmor moved back to County Down in Northern Ireland.
Larmor was a plenary speaker in 1920 at the International Congress of Mathematicians (ICM) in Strasbourg. He also was an invited speaker at the ICM in 1924 in Toronto and in 1928 in Bologna.
Larmor died in Holywood, County Down on 19 May 1942 at the age of 84.
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. He united Lord Kelvin's model of spinning gyrostats (see Vortex theory of the atom) 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 1894 he was referring to as the electron). 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.
Larmor also created the first solar system model of the atom in 1897. He also postulated the proton, calling it a "positive electron". He said the destruction of this type of atom making up matter "is an occurrence of infinitely small probability".
In 1919, Larmor proposed sunspots are self-regenerative dynamo action on the Sun's surface.
Quotes from one of Larmor's voluminous work include:
Parallel to the development of Lorentz ether theory, Larmor published an approximation to the Lorentz transformations in the Philosophical Transactions of the Royal Society in 1897, namely for the spatial part and for the temporal part, where and the local time He obtained the full Lorentz transformation in 1900 by inserting into his expression of local time such that and, as before, and . This was done around the same time as Hendrik Lorentz (1899, 1904) and five years before Albert Einstein (1905).
Larmor, however, did not possess the correct velocity transformations, which include the addition of velocities law, which were later discovered by Henri Poincaré. Larmor predicted the phenomenon of time dilation, at least for orbiting electrons, by writing (Larmor 1897): "individual electrons describe corresponding parts of their orbits in times shorter for the [rest] system in the ratio (1 â v<sup>2</sup>/c<sup>2</sup>)<sup>1/2</sup>". He also verified that length contraction should occur for bodies whose atoms were held together by electromagnetic 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 opposed to the spacetime interpretation of the Lorentz transformation in special relativity because he continued to believe in an absolute aether. He was also critical of the curvature of space of general relativity, to the extent that he claimed that an absolute time was essential to astronomy (Larmor 1924, 1927).
Larmor edited the collected works of George Stokes, James Thomson, and William Thomson.