1740-1784

Swedish astronomer and mathematician remembered for demonstrating that the object discovered by William Herschel on March 13, 1781, was in fact a new planet (Uranus). He further showed that perturbations of its motion could only be accounted for by another more remote planet. Lexell was proven correct when John Adams and Urbain Le Verrier's calculations led to the discovery of Neptune in 1846. Lexell also made important contributions to analysis, spherical geometry, and trigonometry.