5 Things You Didn't Know About Neptune
On September 23, 1846, German astronomer Johann Gottfried Galle discovered the planet Neptune, the eighth planet in our solar system. To celebrate this landmark event in astronomical history, here are five things you probably didn't know about the planet Neptune...
If It Weren't for Uranus' Orbit Misbehaving Mathematically, Neptune Might Not Have Been Spotted Until Later
No one was really searching for a new planet in 1846. However, astronomers who were trying to calculate the orbit of Uranus noticed that they couldn't easily pin down the planet's location mathematically—many times the calculations were off by several degrees. One theory was that another planet was exerting a gravitational effect on Uranus, and two astronomers were able to calculate the existence of this supposed planet, which turned out to be Neptune. Had Uranus' orbit been predictable, no one would have thought to look for another planet just beyond Uranus.
It Only Recently Completed Its First Orbit Since Its Discovery
Neptune takes 165 Earth years to complete one orbit around the sun. That means that Neptune only completed its first orbit in 2011 since its discovery.
The Controversy Over Who First "Discovered" Neptune Was Somewhat Manufactured
Three people are currently credited with discovering Neptune. Two are scientists who worked independently of each other on calculations to prove a planet was affecting Uranus' orbit. These were British mathematician, John Couch Adams, and French astronomer, Urbain Le Verrier. Adams didn't share his results widely, but Le Verrier openly tried to find people to check out his numbers. German astronomer Johann Galle did so a day after receiving the information, and sure enough, he spotted Neptune just one degree away from where Le Verrier had predicted it would be. (Adams' predictions were off by a few more degrees, by the way.) Now, all three are credited with the discovery, and at the time, Adams treated Le Verrier as the true discoverer of Neptune. However, other British scientists weren't about to let the potential victory go to a rival Frenchman and made some noise about who really discovered Neptune. So the controversy wasn't so much about who had the better timing as it was about British egos.
It's the Only Planet in the Solar System (so Far) Whose Discovery Was Predicted Mathematically
So far, every other planet in the solar system has been spotted first and then become the subject of mathematical calculations about orbital position. Neptune was the reverse; first, the math said something should be in a particular spot, and then a human found the planet almost where it was predicted to be.
An Italian Was Really the First Person to Spot Neptune
As usual, there's a caveat to all this "first person to spot" business. An Italian was actually the first person to see Neptune, even before its existence was calculated—but he thought it was a star and thought nothing more of it. That Italian was Galileo Galilei, back in December 1612.