What are facts about the moons of Uranus?

Answer 1

Like all the outer planets, Uranus is surrounded by a swarm of moons. As of 2011, there are 27 known and named moons. Five are large icy satellites that were discovered from Earth, eleven were located by Voyager 2 in 1986, and the rest in telescopic surveys since 1997.

The orbits of the inner 13 moons are intimately connected to the rings of Uranus, which are thin and tenuous. These moons are small, none larger than 162 km in diameter and some as small as only 18 to 30 km. The orbits are thought to have changed substantially since they were first established.

The outer 9 moons are thought to be captured asteroids, and all but one orbit in the opposite direction from the five large moons, and millions of kilometers farther from the planet. The outermost, Ferdinand, averages 20 million km from Uranus and is estimated to require 7.7 Earth years to make a single orbit of the planet.

Although Voyager 2 performed a survey of Uranus' moons, it passed by when tilted Uranus was at the height of southern summer. As a result, only the southern hemispheres of Uranus's moons have ever been imaged by spacecraft. Additionally, the "bull's-eye" pattern of Uranus' rings and moons on the sky meant that Voyager 2 saw only Miranda close-up; the rest of the moons were only seen distantly.