major moon · moon of Uranus
Umbriel
The darkest of Uranus's large moons, an old, cratered world with a mysterious bright ring on the floor of one crater.
- Distance from Earth today
- 2.77 billion km18.52 AU · light: 2 h 34 min
- Distance from the Sun today
- 2.91 billion km19.43 AU
- As of
- 3 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
- Diameter
- 1,169 km
- Mass
- 1,275 × 10¹⁸ kg
- Density
- 1,523 kg/m³
- Mean distance from the planet
- 265,986 km
- Orbital period
- 4.14 days
- Orbital eccentricity
- 0.0040
- Orbital inclination
- 0.1°
Source of the figures: JPL SSD – Planetary Satellites (public domain).
Discovery: 1851 – William Lassell
Description
Umbriel was discovered by William Lassell in 1851, on the same nights he spotted Ariel, and takes its name from a melancholy sprite in Alexander Pope's poem The Rape of the Lock. It is the darkest of Uranus's five major moons, with an ancient surface densely packed with craters and little sign of later geological activity. Its most puzzling feature is Wunda, a crater near the equator whose floor holds a bright ring of unknown origin. Voyager 2 provided the only close-up images in 1986.