Moons of Uranus geometrical albedo is less than 10%. They are composed of water ice contaminated with a dark material—probably radiation-processed organics. The small inner moons constantly perturb each other. The system is chaotic and apparently unstable. Simulations show that the moons may perturb each other into crossing orbits, which may eventually result in collisions between the moons. Desdemona may collide with either Cressida or Juliet within the next 100 million years. Uranus has five major moons: Miranda, Ariel, Umbriel, Titania, and Oberon. They range in diameter from 472 km for Miranda to 1578 km for Titania. All these moons are relatively dark
Fictional planets of the Solar System Fictional planets of the Solar System The fictional portrayal of our Solar System has often included planets, moons, and other celestial objects which do not actually exist in reality. Some of these objects were, at one time, seriously considered as hypothetical planets which were either thought to have been observed, or were hypothesized in order to explain certain celestial phenomena. Often such objects continued to be used in literature long after the hypotheses upon which they were based had been abandoned. Other non-existent Solar System objects used in fiction have been proposed or hypothesized by persons with no scientific standing,