Urbain Jean Joseph Le Verrier (; 11 March 1811 – 23 September 1877) was a French 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
Kepler and
Newton. Le Verrier sent the coordinates to
Johann Gottfried Galle in Berlin, asking him to verify. Galle found Neptune in 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.