Umbriel is the third moon from the planet Uranus and has the least reflective surface. She is the second most heavily cratered moon of Uranus after Oberon. She is similar to her older sister, Ariel, in that she has a numerous amount of canyons and ridges. However, she has larger craters, with her craters measuring up to 210 kilometers in diameter. Her surface seems to have been primarily shaped by these craters. She is good friends with Titania and Oberon.