Alexis Bouvard

Astronomers are searching the distant precincts of the solar system for a possible Planet 9. The search was triggered by the odd orbits of several bodies in the Kuiper Belt — a band of icy objects beyond Neptune, the eighth planet. A team of astronomers suggested that the bodies were pushed by the gravity of a planet up to 10 times as massive as Earth.

If Planet 9 is found, it won’t be the first world discovered by its gravitational influence. Neptune was discovered through its effect on the orbit of Uranus. And the man who first suspected its existence was born 250 years ago tomorrow.

Alexis Bouvard was a French astronomer who came from a humble background. He was a shepherd boy who made his way to Paris at age 18. He was a gifted mathematician, so he got a job at an observatory as a computer.

Bouvard discovered several comets, and used his math skills to plot their orbits. And beginning in the early 1800s, he tried to calculate the orbit of the newly discovered Uranus. But his numbers didn’t add up — he couldn’t find an orbit that made sense.

Bouvard concluded that Uranus must be influenced by the gravity of another planet outside its own orbit. Bouvard died soon afterward, so he couldn’t follow up on his idea. But scientists in France and Britain did follow up. They calculated a possible location for the new planet. Using the work of the French astronomer, an astronomer in Germany found Planet 8 in 1846 — the planet known today as Neptune.

Script by Damond Benningfield