Good Jeans Biography
Source (Google.com.pk)
James Jeans' father was William Tullock Jeans. William Jeans was a parliamentary journalist of Scottish descent who wrote two books on the lives of scientists. The name Hopgood was James mother's maiden name; she came from the north of England. It was a very religious Christian family with James the eldest of the three children and the only boy. James' family moved to Brighton when he was eighteen months old then, when he was three years old, they moved to London.
Jeans was educated in Merchant Taylor's School in London which he entered in 1890. The first topic which interested him was classics but soon his interests turned towards mathematics. An excellent mathematics teacher at the school encouraged Jeans' interest in the subject but from the time he was a young child he had shown a fascination with numbers. Several stories about his remarkable abilities as a child indicate both an interest and curiosity about numbers and an outstanding memory. Milne relates in [5] that:-
His interest in numbers was early and deep-seated: he not only factorised cab-numbers, but retained in his memory the numbers that he encountered ... At the age of seven he found his father's book of logarithms, tried to discover what they were for but failed, and learnt the first twenty or so seven-figure logs by heart, and remembered them until near the end of his life.
Jeans went to Trinity College Cambridge in October 1896 having won a mathematical scholarship. There he was a fellow student with G H Hardy who was in the same year. He was taught as an undergraduate at Cambridge by J W L Glaisher, W W Rouse Ball, A N Whitehead, R A Herman and E T Whittaker. He was Second Wrangler in the Mathematical Tripos examinations of 1898 (ranked seconf in the list of First Class students) and was awarded a First Class degree in the Mathematical Tripos of 1900. Although he would not return again to pure mathematics, Jeans wrote a paper on the theory of numbers while an undergraduate. Both Jeans and Hardy were awarded a Smith's prize with 'unspecified relative merit'. Jeans was awarded an Isaac Newton Studentship in astronomy and optics, then in 1901 he was elected a Fellow of Trinity.
Already while he was still an undergraduate Jeans had gained experience in experimental physics having worked in the Cavendish Laboratory during the academic year 1899-1900. He was very active in research publishing work on a variety of topics in applied mathematics, physics and astronomy from 1901 onwards. In particular he published on the specific heats of gases and the mechanism of radiation. However this was achieved despite health problems. He suffered from tuberculosis during 1902 and 1903 and he had to go to a sanatorium to recover. He spent some time at a sanatorium in Ringwood, Lyndhurst, then later at a sanatorium in Mundesley.
During this period of forced rest due to the tuberculosis, Jeans worked on his first major text The dynamical theory of gases. It was a book which incorporated much of Jeans own researches. Milne writes that the work includes [5]:-
... the theory of the equipartition of energy and Maxwell's law, and the chapters in which he ... treats the statistical mechanics of a gas ... sweep the reader off his feet by their charm of expression, boldness of exposition, and power of generality.
Milne writes that studying this work when he was a student was one of his:-
... most vivid and pleasurable mathematical experiences.
He goes on to show what an impact the work had on him as the start of his career:-
It is all a joyous adventure. Pure mathematicians will know what I mean when I describe the effect of the impact of Jeans' statistical mechanics on a young man's mind as comparable with the impact of a first introduction to the theory of functions of a complex variable. One is astounded that such a rich harvest of results arises from so thin a sowing of assumptions and definitions.
The dynamical theory of gases is far more than an account of Jeans' own research. It is a scholarly account of the whole area including a description of the physical properties of gases. Viscosity and conduction of heat are other topics which he included. The book benefits from Jeans' expertise in several areas: his physical intuition, his mathematical skills, and not least his ability to write with extraordinary clarity.
In 1905 Jeans published a paper in the Philosophical Magazine which showed the impossibility of the ether reaching thermal equilibrium with matter. Of course Planck had announced in 1900 his formula, now known as Planck's radiation formula, on black-body radiation but Jeans was strongly opposed to Planck's results, see for example [4]. Of course Jeans' paper can be seen as a mathematical "proof" that classical physics does not suffice, but it is interesting to note that his pre-quantum ideas concerning the very long time required for systems to come into equilibrium and the observed breakdown of equipartition in specific heat measurements on molecular gases have been used again in relatively recent times more than 80 years after Jeans introduced them. We should also note that Jeans' paper was written after the Michelson-Morley experiment disproved the existence of the ether, and in the same year that Einstein published the special theory of relativity.
Jeans was appointed a Lecturer in Mathematics at Cambridge in 1904, then he lectured at Princeton from 1905 until 1909 where he was Professor of Applied Mathematics. During this period he published his second major text Theoretical Mechanics (1906) and then, in 1907, he was elected a Fellow of the Royal Society.
In 1907 Jeans married an American, Charlotte Tiffany Mitchell, who became a poet of some note. He published The Mathematical Theory of Electricity and Magnetism in 1908 while still in the United States. In 1909 Jeans returned to England and the following year he was appointed Stokes Lecturer in Applied Mathematics at Cambridge. He only held this post until 1912 when he retired to Guildford to devote himself completely to mathematical research and writing books.
Certainly Jeans continued to produce a remarkable output, and he wrote an excellent report on Radiation and Quantum Theory for the Physical Society in 1914. In this work he showed that he had come to accept Planck's formula on black-body radiation which he had rejected in 1905. Although World War I prevented Jeans' report from being widely read in Britain until after 1918, it then had a major impact on having quantum theory and the Bohr theory of the atom accepted by the British scientific community.
In 1917 Jeans won the Adams Prize from the University of Cambridge for his essay entitled Problems of cosmogony and stellar dynamics. This was published as a book in 1919. The high work-load was taking its toll, however, and in 1917 Jeans began to show his first signs of heart problems. In 1918 Jeans and his family moved to Dorking, Surrey, where they occupied a fine house Cleveland Lodge. He was a great lover of music and in his home he had an organ built which he often played for three or four hours a day. Despite considerable talents, he never played in public, not even playing for his friends.
There was a long running scientific argument between Jeans and Eddington over the mechanism by which energy was created in stars. Jeans favoured, incorrectly as it turned out, the theory that the energy was the result of contraction while Eddington, correctly of course, believed it resulted from a slow process of annihilation of matter.
Jeans' work in fluids led him to believe that Laplace's nebular hypothesis for the creation of the solar system was incorrect. He had studied compressible fluids in his Adams Prize essay. Examining the stability of a rotating mass of fluid he concluded that the result of George Darwin which showed that a pear shape of fluid was stable, was wrong. Taking the calculations to a higher degree of accuracy he showed that the shape was in fact unstable. He deduced from these results a mechanism whereby the rotating mass can split into two, giving a model for double star formation.
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