One of the major satellites of Uranus, discovered by Gerard Kuiper in 1948. Its radius is 240 × 234.2 × 232.9 km; mass 0.659 × 1020 kg; mean density 1200 kg/m3; albedo 0.27; gravity 0.01 (Earth = 1); distance from Uranus 129 850 km. The surface temperature is about 43 K. Miranda is composed of rocky material and water ice in approximately equal proportions. The first pictures of the surface were provided in 1986 by Voyager 2 as it passed close to the satellite to gain a gravity assist to take it to Neptune. The surface of Miranda comprises areas of rolling, cratered terrain, with grooves, valleys, and cliffs, one more than 15 km high. Within this terrain there are three coronae. These are square, with rounded corners, up to about 260 km across, and contain dark and bright patches and sets of parallel ridges and grooves. It is now believed that the crust of Miranda was pulled apart by internal forces as the interior was evolving and the coronae formed above major upwellings of partially melted ice, and tidal distortions by Uranus caused heating.
Subjects: Earth Sciences and Geography.