Moons keep Uranus's rings in order

2019-03-07 09:07:06

By Jeff Hecht AFTER a 14-year search the Hubble Space Telescope has found two tiny moons orbiting Uranus only previously seen by a planetary probe. The find supports a theory that the moons—one inside Uranus’s main ring and one outside—act as “shepherds”, keeping the ring from dispersing. The Voyager 2 spacecraft discovered the moons, named Cordelia and Ophelia, as it whizzed passed the planet in January 1986. But researchers could not get a precise fix on their orbits. Even though astronomers immediately began training their telescopes on Uranus, light from the main ring blotted out the moons. However,