Urbain Le Verrier

Urbain Jean Joseph Le Verrier (1811-1877) was a French astronomer and mathematician renowned for one of the most celebrated triumphs of mathematical astronomy. In the 1840s, working purely from calculations based on irregularities in the observed orbit of Uranus, Le Verrier predicted that an unseen planet's gravity was responsible for the discrepancies, and he calculated the position where that planet should be found. On September 23, 1846, astronomers at the Berlin Observatory pointed their telescope to the location Le Verrier had specified and discovered Neptune within about one degree of his prediction, a landmark demonstration that celestial mechanics could reveal unseen bodies through mathematics alone. Le Verrier later served as director of the Paris Observatory, where he worked to modernize French astronomical research, and he also studied irregularities in the orbit of Mercury that decades later helped point toward the need for Einstein's general theory of relativity.