Which astronomer discovered the planet Neptune?

Neptune was the first planet to be discovered by using mathematics. After the discovery of Uranus in 1781, astronomers noticed that the planet was being pulled slightly out of its normal orbit. John Adams of Britain, and Joseph Leverrier, of France, used mathematics to predict that the gravity from another planet beyond Uranus was affecting the orbit of Uranus. A young astronomer, Johann Gottfried Galle, decided to search for the predicted planet and observed Neptune for the first time in 1846.