What are facts about the moon Ariel?

Ariel is one of the largest moons of Uranus and the fourth largest overall, with a diameter of about 1,158 kilometers (720 miles). It has a mixed surface of bright, icy terrain and darker regions, suggesting a history of geological activity, including possible cryovolcanism. Ariel's surface is marked by canyons and impact craters, indicating it has undergone significant geological processes. Discovered by William Herschel in 1851, Ariel orbits Uranus at a distance of approximately 191,000 kilometers (118,000 miles).