Rodolphe Radau

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Jean Charles Rodolphe Radau (born January 22, 1835 in Angerburg , East Prussia , † December 21, 1911 in Paris ) was a Franco-German astronomer.

life and work

Radau's father was the director of an institution for the deaf and the mentally handicapped. Radau went to school in Königsberg and studied mathematics and astronomy at the University of Königsberg from 1852 to 1857 (with Christian August Friedrich Peters and Carl Gottfried Neumann , among others ), where he was a volunteer at the observatory in Königsberg as early as 1855/56. After he had worked on the astronomical and geodetic observations of the French traveler Antoine d'Abbadie d'Arrast (1810-1897) in Ethiopia and made contacts, he went to Paris in 1858, where he stayed for the rest of his career.

From 1866 he was a science journalist at the Revue des Deux Mondes , where he was soon editor. He also previously wrote numerous articles as a science journalist in a wide variety of journals, for example the Journal des Débats . He was known for his brilliant style and had wide-ranging interests, for example he also wrote a libretto for Jacques Offenbach . After a short break due to the Franco-Prussian War (he did not become a French citizen until 1873), he was back in Paris, edited the Bulletin des Sciences Mathematiques with Gaston Darboux and was a co-founder of the Bulletin Astronomique , in which he published a lot. In addition to his editorial and journalistic activities, he continued his scientific work and won the Prix ​​Damoiseau of the French Academy of Sciences in 1892 for a thesis on the disturbance of the moon orbit by the planets. Because of this work he was accepted into the French Academy of Sciences in 1897 as the successor to Félix Tisserand (with whom he also worked several times).

He became a member of the Bureau des Longitudes in 1899 and devoted himself to the calculation of lunar ephemeris based on the theory of Charles Eugène Delaunay . The creation of the tables, which had already been started by Delaunay and Tisserand, ran into difficulties (the disturbance from the planets had to be completely redeveloped by Radau) and could only be completed by him much later ( Tables de la lune fondées sur la théorie de Delaunay , Bureau des Longitudes, Gauthier-Villars 1911). Another work that received much attention at the time was devoted to the astronomical theory of refraction in the atmosphere (Annales de l'Observatoire de Paris, 1881 and 1889), for which he also calculated tables, and a work on the figure of the earth, where he found the differential equation von Clairaut solved with a transformation named after him (also known as the Radau approximation).

In 1864 he published an essay in which he was one of the first to apply elliptic functions to the three-body problem . By evaluating the observations of the English astronomer Richard Christopher Carrington , he also determined the period of rotation of the sun in different latitudes in 1864. Radau published several popular science books, for example on meteorology and acoustics (where he made the theories of Hermann von Helmholtz known in France).

In 1871 he was awarded an honorary doctorate from the University of Königsberg. A crater on Mars bears his name.

Fonts

  • Les Planètes au delà de Mercure , Paris, Au Bureau de Cosmos, 1861 ( online )
  • Recherches modern sur la conductibilité calorifique , 1862
  • Le Specter solaire , 1863
  • Sur la formule barométrique , 1864
  • Sur la base scientifique de la musique: analysis des recherches de M. Helmholtz , 1865
  • Sur les ereurs personnelles , 1865
  • Théorie des battements et des sons résultants d'après M. Helmholtz , 1865
  • L'Acoustique, ou Les phénomènes du son , Hachette 1867
  • L'Origine de l'homme d'après Darwin , 1871
  • Les Observatoires de montagne. Les nouveaux observatoires météorologiques du Puy-de-Dôme et du Picdu-Midi de Bigorre , Gauthier-Villars 1876
  • La Production houillère et l'exportation du charbon en Angleterre et en France , 1876
  • Progrès récents de l'astronomie stellaire , 1876
  • La Lumière et les climats , 1877
  • Actinometry , 1877
  • Les Radiations chimiques du soleil , 1877
  • La Photographie et ses applications scientifiques , 1877
  • La Constitution intérieure de la terre , 1880
  • Le Rôle des vents dans les climats chauds , Gauthier-Villars 1880
  • Le Magnétisme , Librairie Hachette 1881
  • Travaux concernant leproblemème des trois corps et la théorie des perturbations , 1881
  • La Météorologie nouvelle et la prévision du temps , 1883
  • Les Vêtements et les habitations dans leurs rapports avec l'atmosphère , 1883

Web links

Individual evidence

  1. ↑ Bigourdan, Astronomical News 1912
personal data
SURNAME Radau, Rodolphe
ALTERNATIVE NAMES Radau, Jean Charles Rodolphe (full name)
BRIEF DESCRIPTION German-French astronomer
DATE OF BIRTH January 22, 1835
PLACE OF BIRTH Angerburg , East Prussia
DATE OF DEATH December 21, 1911
Place of death Paris