query: How many moons does Uranus have?
passage: 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.[1] 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.[2] The largest of these five, Titania, is 1,578km 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.[3]
passage: Hans Scholl (astronomer)
Hans Scholl (b. 1942) is a German astronomer, who worked at the Astronomisches Rechen-Institut in Heidelberg, Germany, and at the Côte d'Azur Observatory in Nice, France. In 1999, he was part of a team that discovered three moons of Uranus: Prospero, Setebos and Stephano. He has also co-discoverered 55 minor planets together with Italian astronomer Andrea Boattini at ESO's La Silla Observatory site in northern Chile during 2003–2005.