The French astronomer who co-discovered the planet Neptune, Urbain Jean Joseph Leverrier, was born on this day in 1811. Based on hints that Uranus veered slightly from the orbit predicted at the time, Leverrier proposed that an unknown planet beyond Uranus was influencing the orbit. In 1846, he and 24-year-old English astronomer John Couch Adams each independently published several papers on the hypothetical planet's position and asked several observatories to search for it.
German astronomer Johann Gottfried Galle and his Dutch colleague Heinrich Louis d'Arrest soon found the eighth planet from the sun, which is now known to take 165 years to complete an orbit, within 1 degree of Leverrier's coordinates. The greenish-hued orb was dubbed Neptune, after the Roman god of the sea. Leverrier devoted the rest of his life to compiling a comprehensive analysis of the masses and orbits of the solar system's planets and their subtle effects on one another.
[Source: Roy Porter, Ed., The Biographical Dictionary of Scientists (Oxford University Press, ed. 2, 1994).]