On this day, there are so many people I could have chosen to write about. There is the least interesting of the Three Stooges. There are two men who have been highly effective at making the United States a far worse country. And there are lots of good film directors, writers, and composers. But in the end, the choice was easy.

On this day in 1811, the great mathematician Urbain Le Verrier was born. He’s my kind of guy because he made great discoveries in astronomy without ever having to leave him room. What’s more, unlike other great mathematicians, I completely understand his work because it is mostly just celestial mechanics. He is best known for having predicted that the planet Neptune existed based upon discrepancies in the orbit of Uranus. (Note: another great mathematician, John Couch Adams, did the same work at roughly the same time.)

Le Verrier was also the first person to note problems with the Newtonian calculation of the orbit of Mercury. It was thought that this might be due to another planet as was the case with Uranus. But the real reason for the discrepancies had to wait almost 50 years after Le Verrier’s death when Einstein published his General Theory of Relativity. But Le Verrier’s calculations were the basis of one of the first tests of the theory.

Here is Richard Feynman talking about both of Le Verrier’s discoveries:

Happy birthday Urbain Le Verrier!