Urbain Jean Joseph Le Verrier (French: [yʁbɛ̃ ʒɑ̃ ʒozɛf lə vɛʁje]; 11 March 1811 – 23 September 1877) was a French astronomer and mathematician who specialized in celestial mechanics and is best known for predicting the existence and position of Neptune using only mathematics.
The calculations were made to explain discrepancies with Uranus's orbit and the laws of Johannes Kepler and Isaac Newton. Le Verrier sent the coordinates to Johann Gottfried Galle in Berlin, asking him to verify. Galle found Neptune the same night he received Le Verrier's letter, within 1° of the predicted position.
The discovery of Neptune is widely regarded as a dramatic validation of celestial mechanics, and is one of the most remarkable moments of 19th-century science.
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