The Solar System

Gas Giants

What are the rings of Uranus like?

The first nine rings of Uranus were discovered in 1977. When Voyager 2 flew by Uranus in 1986, it found two new rings, plus a number of ring fragments. About twenty years later, astronomers using the Hubble Space Telescope found two more faint rings far out past these eleven, bringing the total to thirteen. All are composed of small pieces of dust, rocky particles, and ice.

The eleven interior rings occupy the region between twenty-four thousand and thirty-two thousand miles (thirty-eight thousand and fifty-one thousand kilometers) from the planet’s center. Each ring is between 1 to 1,500 miles (1 to 2,500 kilometers) wide. The additional presence of partial rings suggests that the rings of Uranus may be much younger than the planet they encircle; it is possible that the rings are made of fragments of a broken moon. The eleventh-farthest ring, called the epsilon ring, is particularly interesting; it is very narrow and composed of ice boulders. Two of the small moons of Uranus, Cordelia and Ophelia, act as shepherd satellites to the epsilon ring. They orbit the planet within that ring, and are probably responsible for creating the gravitational field that confines the boulders into the pattern of a ring.


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