Moons of Uranus these five, Titania, is 1,578 km in diameter and the eighth-largest moon in the Solar System, and about one-twentieth the mass the Earth's Moon. The orbits of the regular moons are nearly coplanar with Uranus's equator, which is tilted 97.77° to its orbit. Uranus's irregular moons have elliptical and strongly inclined (mostly retrograde) orbits at large distances from the planet. William Herschel discovered the first two moons, Titania and Oberon, in 1787, and the other three ellipsoidal moons were discovered in 1851 by William Lassell (Ariel and Umbriel) and in 1948 by Gerard Kuiper (Miranda). These five have planetary mass,
Devil's Planet Devil's Planet "Devil's Planet" is the twenty-second episode of the second series of the British sci-fi television series "" (and the forty-sixth overall episode of the programme). The screenplay was written by Michael Winder; the director was Tom Clegg. The original title of the episode was "Devil's Moon". The final shooting script is dated 9 September 1976 and live-action filming began on Monday 1 November 1976 lasting through to Thursday 18 November 1976. The episode was first broadcast in the U.K. on 1 September 1977. 2306 days after leaving Earth orbit, the Moon is passing a solar system containing a