Caliban, a moon of Uranus
4,493,126 miles
45 miles
Caliban is one of Uranus’s outer irregular moons and follows a retrograde orbit, meaning it travels around the planet in the opposite direction to Uranus’s rotation. With a diameter of about 72 kilometres (45 miles), Caliban is the second-largest irregular moon of Uranus after Sycorax.
It was discovered in September 1997 by astronomers Brett J. Gladman, Philip D. Nicholson, Joseph A. Burns, and John J. Kavelaars, using the 200-inch Hale Telescope at Palomar Observatory in California. Because of its great distance from Uranus and relatively small size, Caliban appears very faint, even through powerful telescopes.
Caliban’s retrograde motion and irregular orbit suggest it did not form alongside Uranus’s regular moons but was instead captured by the planet’s gravity, possibly from the Kuiper Belt or as an independent object wandering through the outer Solar System.
Caliban is named after a character in William Shakespeare’s The Tempest. In the play, Caliban is the deformed and often bitter son of the witch Sycorax. He is the original inhabitant of the island where Prospero and Miranda live. Although depicted as brutish and resentful, Caliban is also a complex character, sometimes poetic, sometimes vengeful, whose relationship with Prospero is filled with conflict.
The name follows the convention of naming Uranus’s moons after characters from Shakespeare’s plays or, in some cases, Alexander Pope’s poetry. Caliban’s “mother” in the play, Sycorax, is also honoured in Uranus’s moon family.
