Le Verrier, Urbain Jean Joseph

Le Verrier, Urbain Jean Joseph

(ürbăN` zhäN zhôzĕf` ləvĕryā`), 1811–77, French astronomer who made calculations that led to the discovery of the planet NeptuneNeptune,
in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolution is about 165 years.
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. In considering the perturbations of UranusUranus
, in astronomy, 7th planet from the sun, at a mean distance of 1.78 billion mi (2.87 billion km), with an orbit lying between those of Saturn and Neptune; its period of revolution is slightly more than 84 years.
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, Le Verrier made calculations indicating the presence of an unknown planet in an orbit outside that of Uranus. At the time, this was considered the crowning achievement of mathematical astronomy. The same conclusion had been reached by John Couch AdamsAdams, John Couch,
1819–92, English astronomer, grad. St. John's College, Cambridge, 1843. By mathematical calculation based on irregularities in the motion of Uranus, he predicted the position of the then unknown planet Neptune.
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 a little earlier but had not been published, so Le Verrier was initially given sole credit for the discovery of Neptune, which was actually first observed, as a result of Le Verrier's instructions, by Johann GalleGalle, Johann Gottfried
, 1812–1910, German astronomer. He is noted for his discovery of the planet Neptune, Sept. 23, 1846, by following the guidance of calculations by Le Verrier.
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 in 1846. After much controversy both Adams and Le Verrier were honored as responsible for the planet's discovery. In 1854, Le Verrier became director of the Paris Observatory.