Miranda orbits Uranus every c. 34 hours at an approximate distance of 129,390 km (about 81,000 miles). It is likely to comprise silicate rock and organic compounds on the inside with an exterior comprising mostly water ice. The surface appears tortured with enormous grooves and huge canyons pointing to immense geological upheavals in the past. Quite soon after it formed, Miranda was in a 3:1 orbital resonance with the moon Umbriel. One result of this is that Miranda's orbit would have been much more eccentric. The resulting tidal forces, changing as it orbited Uranus, would have generated internal heat from friction resulting in the extreme geological activity. In any event, Miranda escaped the resonance some time in the past, and now orbits in a near circular path. It has an average diameter of about 472 km.
