On the night of September 23, 1846, Neptune was discovered and observed by Johann Galle with the help of the mathematical predictions of Urbain Le Verrier. Disturbances in the orbit of Uranus had lead astronomers and mathematicians to believe that another planet was beyond Uranus in the Solar System. While other mathematicians were also working on the mystery of Uranus' orbit, Le Verrier determined the mass and position of the unknown planet. After figuring out this information, Le Verrier asked Galle to search for the planet in the night's sky, which meant that Neptune, which is invisible to the naked eye, was the first planet found by using mathematical prediction rather than solely through observation. While Galle discovered Neptune, he refused to take credit for the discovery, saying that it was Le Verrier's mathematics that really discovered the planet. While Le Verrier and Galle are credited with the discovery, Neptune had been observed by Galileo Galilei in 1613, Jerome Lalande in 1795, and John Herschel in 1830. However, none of these astronomers realized what they were looking at was a planet.
Items in Our Collection:
Astronomical discovery by H H Turner
Archives of the universe : a treasury of astronomy's historic works of discovery by Marcia Bartusiak