Who Discovered Neptune?
Written by Fraser Cain
Five of the planets in the night sky are easy to see with the unaided eye, and have been known since ancient times. Uranus is just bright enough that you can see it in a perfectly dark place and know where to look. But Neptune can only be seen in a telescope. And since telescopes have only been around for a few hundred years, Neptune was discovered recently. So, who discovered Neptune?
The mathematician Alexis Bouvard published a series of astronomical tables detailing the orbit of Uranus. Over time, several astronomers realized that there had to be some additional planet deeper out in the Solar System that was influencing the motion of Uranus with its gravity. They set to work calculating where this additional planet might be located in the Solar System.
Two astronomers, Britain's John Couch Adams and France's Urbain Le Verrier were worked out the position of the hypothetical 8th planet independently from each other. And both had a difficult time convincing their colleagues to spend any time actually looking where they suggested the planet might be.
Berlin Observatory astronomer Johann Gottfried Galle was urged by Le Verrier to search for the planet. He spent one evening searching in the region suggested by Le Verrier, and found it within 1 degree (twice the width of the full moon) of Le Verrier's calculations.
After the discovery, there was rivalry between England and France about who should get credit for finding Neptune, Adams or Le Verrier. The international astronomy community agreed that the two astronomers should share credit for the discovery.
And that is how Neptune was discovered.
Would you like to know how Uranus was discovered?
Of course, this is just a shortened version of the discovery of Neptune. If you'd like to read more, check out this article that talks about the mathematical discovery of planets. And here's more information on Le Verrier.
We have recorded an entire episode of Astronomy Cast just about Neptune. You can listen to it here, Episode 63: Neptune.
Filed under: Astronomy
