Astronomers studying Uranus encountered a mystery. The planet's position in the sky was always slightly different from its predicted orbit. The most reasonable explanation was that the gravity of some undiscovered planet was affecting Uranus's orbit. In 1846, an English university student named John Couch Adams used mathematical calculations to figure out where the unknown planet would probably be located in the sky. He tried to convince Sir George Airy, the Astronomer Royal, to look for the planet. Airy wasn't interested. At around the same time, French astronomer Urbain Jean Joseph Leverrier had also calculated the location of the unknown planet. He
