Moons of Uranus
Uranus, the seventh planet of the Solar System, has 27 known moons, all of which are named after characters from the works of William Shakespeare and Alexander Pope. Uranus's moons are divided into three groups: thirteen inner moons, five major moons, and nine irregular moons. The inner moons are small dark bodies that share common properties and origins with Uranus's rings. The five major moons are massive enough to have reached hydrostatic equilibrium, and four of them show signs of internally driven processes such as canyon formation and volcanism on their surfaces. The largest of 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.
Uranus (mythology)
The ancient Greeks and Romans knew of only five 'wandering stars' (, "planētai"): Mercury, Venus, Mars, Jupiter, and Saturn. Following the discovery of a sixth planet in 1781 using a telescope, there was long-term disagreement regarding its name. Its discoverer William Herschel named it Georgium Sidus (The Georgian Star) after his monarch George III. This was the name preferred by English astronomers, but others such as the French preferred "Herschel". Finally, the name "Uranus" became accepted in the mid-19th century, as suggested by astronomer Johann Bode as the logical addition to the existing planets' names, since Mars ("Ares" in Greek), Venus, and Mercury were the children of Jupiter, Jupiter ("Zeus" in Greek) the son of Saturn, and Saturn (Cronus in Greek) the son of Uranus. What is anomalous is that, while the others take Roman names, "Uranus" is a name derived from Greek in contrast to the Roman Caelus.