Urbain Jean Joseph Leverrier

Born Mar. 11, 1811, in Saint-Lô; died Sept. 23, 1877, in Paris. French astronomer. Member of the Paris Academy of Sciences (1846).

Leverrier graduated from the Ecole Polytechnique in Paris in 1833. In 1846 he was appointed to the chair of celestial mechanics at the University of Paris. In 1854 he was named director of the Paris Observatory. His works were devoted to the solution of the problems of celestial mechanics. In 1839 he conducted an investigation of the secular variations of planetary orbits and studied the problem of the stability of the solar system. In 1845, at the suggestion of D.-F. Arago, he undertook the study of the irregularities in the motion of the planet Uranus and showed that their cause was an unknown planet located beyond the orbit of Uranus. He calculated, independently of J. C. Adams, the position of this planet (later named Neptune) in 1846. It was discovered by J. G. Galle that same year at the place indicated by Leverrier. The discovery of Neptune by means of precomputations is one of the greatest events in theoretical astronomy.

In 1849, Leverrier proposed a revision of the theory of the motion of the planets. He worked on this revision and on the calculation of planetary tables for the rest of his life. His planetary theory, which required enormous computational efforts on his part, was distinguished by a high degree of accuracy. It was used for a long time in the compilation of astronomical ephemerides, that is, tables of the positions of the bodies of the solar system. The calculations of the astronomical almanac issued by the Bureau of Longitudes in Paris are based on them. Leverrier also discovered the secular motion of the perihelion of Mercury, something that cannot be explained by Newton’s law of gravitation. His most important works were published in the Annales de l’observatoire de Paris, which he founded.