George Darwin

See also: Darwin

Sir George Howard Darwin was born with Downe the July 9th 1845 and died in Cambridge the December 7th 1912. He was the second wire of the famous British biologist Charles Darwin, founder of the Théorie of the evolution, and his wife Emma Darwin born Wedgwood. While being interested in a very different scientific discipline, it was like his/her father a British scientist except par and left, like this one, an indelible print in the history of sciences. Still now many of its work remain of topicality.

He studied under Charles Pritchard, then gained a purse to finance his studies with the college Trinity of the Université of Cambridge. He there was allowed as a lawyer in 1874, but went back well quickly to scientific studies. In 1883 it becomes “Professor Plumien d' Astronomie and of Experimental Philosophy” at this same university of Cambridge. It occupied this station until its death in 1912. He was member of the Royal Société of London.

He accepted the Gold medal of Royal Astronomical Society in 1892, and was president of this institution later some time. Its principal work related to what one now calls the Géodynamique, of which it was with Lord Kelvin and A.E.H. Love one of the most famous pioneers. It was illustrated in the theory of the tides which it made rest on solid mathematical bases; it establishes the first classification of the most important components of tide (currently called “classification of Darwin” and forged the symbols (always employed) for these partial tides, such M₂ to indicate the principal semi-diurnal tide caused by the Moon (“M” for moon =lune in English) or S₁ to indicate an important diurnal tide caused by the Sun (“S” for sun =soleil in English). He proposed a theory of the formation of the Moon which knew its hour of glory: according to Darwin, the Moon would have been ejected Earth by leaving like scar the basin of the Pacific. That would have occurred in a very remote past when the Earth rotated so much quickly that the duration of the day was only slightly higher than four hours and that gravific attraction at the equator was less than the centrifugal force. Of course, have regard to our current knowledge, this theory is hardly any more accepted by the very large majority of the geophysicists, sometimes but certain astronomers and certain geochemists try to revive it in amended form. George Howard Darwin is also extremely known among the specialists for her marvellous work relating to on the one hand the figure in the Earth, field in which it extended work of Clairaut and of Laplace, which remained confined with the first order of approximation, the second order of approximation (with the approximation of Darwin, the figure of the Earth is not any more one strict spheroid as in the case of the approximation of Clairaut and Laplace), relating to on the other hand the friction of the tides causing the braking of the rotation of the Earth and the concomitant lengthening of the distance the Ground-Moon during geological times. During years 1860, it and Kelvin could prove, on the basis of recording of marigraphs installed in various ports of the British Empire, that the material being in lower part of the Earth's crust was not liquid as it then was thought, but at least as solid as steel. In Astronomie and Celestial mechanics beautiful work of Darwin on the double stars was also innovating. The very vast scientific literature, gathered in five volumes of its Scientific Papers , testifies to the variety, the richness and the depth of the work left by this brilliant British scientist. For the layman, his book of popularization concerning the phenomena of tide always remains of a reading extremely pleasant and enriching, in spite of the passage of time.

George Howard Darwin married in 1884 Martha (Maud) of Puy, American of Philadelphia. The couple had four children (two wire and two girls), among whom at least two reached also a certain celebrity. It is about Gwen Raverat (1885 - 1957), which was illustrated in the artistic field; of Charles Galton Darwin (1887 - 1962), which was a famous physicist, especially in the field of theoretical atomic physics, Margaret Elizabeth Darwin (1890 - 1974), which married Sir Geoffrey Keynes, and of William Robert Darwin (1894 -?).

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