Moons of Uranus

The moons of Uranus are natural satellites orbiting Uranus, the seventh planet from the Sun. More than twenty are known, but only five are large: Miranda, Ariel, Umbriel, Titania, and Oberon. The others are small moons, some of which were discovered using ground-based telescopes and space imagery.

The names of the moons derive from characters in the works of William Shakespeare and the poetry of Alexander Pope. This is a naming system distinct from other planets, whose moon names are generally taken from Greek and Roman mythology.

Discovery

William Herschel discovered the two largest moons, Titania and Oberon, in the eighteenth century. Ariel, Umbriel, and Miranda were discovered in subsequent decades. The Voyager 2 spacecraft in 1986 surveyed the Uranian system in its entirety, and revealed additional small moons not previously known.

The five large moons

Titania and Oberon are the largest, composed of ice and rock in combination. Ariel has the brightest surface, showing signs of past geological activity. Umbriel has the darkest surface. Miranda, the smallest of the five, has a heavily fractured surface marked by cliffs and deep canyons.

Small moons

There is a group of inner moons orbiting very close to Uranus's rings, which influence the rings' structure. There are also outer moons with distant orbits, many of which orbit in a direction opposite to the planet's rotation, suggesting they were captured.