ARAG Dominique Francois (Arago Dominique Francois Jean)( Fantsuzsky physicist, astronomer and politician.)
Comments for ARAG Dominique Francois (Arago Dominique Francois Jean)
Biography ARAG Dominique Francois (Arago Dominique Francois Jean)
Born February 26, 1786 ESTAGEL (Eastern Pyrenees). He studied at the Ecole Polytechnique in Paris. In 1809-1831 - professor of analytic geometry in this school. In 1830 was appointed director of the Paris Observatory and the Permanent Secretary of the Paris Academy of Sciences. In 1830-1848 - member of the Chamber of Deputies from District Lower Seine. After the revolution of 1848 joined the interim government, served as Navy Minister.
The scientific work of Arago devoted magnetism, optics, astronomy. In 1811 he opened the chromatic polarization of light (regardless of J. Biot and D. Brewster), first observed the rotation of the plane of polarization of light in quartz. In 1820 he discovered the magnetization of iron filings near the conductor (magnetic induction), and in 1824 demonstrated the effect of a rotating metal plate on a magnetic needle (magnetism of rotation). Established a link between the northern lights and magnetic storms (changes in the magnetic field of the Earth).
Arago constructed a series of optical devices used in astronomy, physics and meteorology: polariscope (1811), ulanometr (device for measuring the blueness of the sky) (1815), photometer to determine the star's luminosity (1833).
Arago adhered to the wave theory of light, Fresnel and in 1838 described a scheme of experiments to compare the speed of light in air and the denser medium - water and glass (placed in 1850 A. Fizeau and Foucault). On orders Arago U. Le Verrier had a mathematical analysis of deviations in the movement of the planet Uranus, which resulted in the open - 'on the tip of the pen' - the planet Neptune.
Died Arago in Paris on October 2, 1853.