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Moon of Uranus
Miranda
A small, patchwork moon of Uranus with the tallest known cliff in the solar system
Key facts
- Diameter
- About 292 miles / 470 km (mean radius 235.8 km); NASA rounds this to about 500 km
- Distance from Uranus
- About 80,700 miles / 129,800 km
- One orbit
- About 1.41 Earth days (about 34 hours)
- One day (rotation)
- Same as its orbit; one face always points at Uranus
- Discovered
- 16 February 1948, by Gerard P. Kuiper at the McDonald Observatory, Texas
- Named after
- Miranda, Prospero's daughter in Shakespeare's The Tempest
- Surface
- Water ice and rock; coronae, grooves and cliffs; about minus 213 °C
- Tallest cliff
- Verona Rupes, an estimated 3.1 to 6.2 miles / 5 to 10 km high
- Brightness
- Reflects about a third of the sunlight that hits it
- Visited by
- Voyager 2 only, flying past 17,600 miles / 28,260 km away on 24 January 1986
- Uranus's known moons
- 29, as of August 2026
About Miranda
Miranda is a small moon. It goes round the planet Uranus. It is made of ice and rock. Miranda looks like a patchwork quilt. It has huge cracks and cliffs. One cliff is taller than any mountain on Earth. Drop a stone from the top. It falls for ten whole minutes. Miranda is very, very cold. Only one spacecraft has seen it. It was called Voyager 2. It flew past in 1986. It took the only close-up photos we have.
Miranda is the smallest and innermost of the five large moons of Uranus. It is about 470 km across, roughly one-seventh the size of our Moon. It orbits Uranus at a distance of about 130,000 km. One orbit takes only about 34 hours, less than two Earth days.
Like our Moon, Miranda always keeps the same face towards its planet. Astronomers say it rotates once for every orbit it makes. Miranda is a rough sphere made of about half ice and half rock. Its surface is a strange jumble of grooves, ridges and cracked plains.
Three of these odd patches are called coronae, and one is named Inverness. The most famous feature is Verona Rupes, a cliff 5 to 10 km high. Miranda's gravity is so weak that a dropped rock falls for ten minutes. The surface is bitterly cold, around minus 210 degrees Celsius.
The astronomer Gerard Kuiper discovered Miranda in photographs in 1948. Voyager 2 flew past on 24 January 1986 and remains its only visitor.
Miranda is the innermost and smallest of the five major moons of Uranus. JPL gives its mean radius as 235.8 km, so its diameter is about 470 km; NASA's page rounds this to about 500 km, or roughly one-seventh the diameter of Earth's Moon. It orbits about 129,800 km from the centre of Uranus, completing one circuit every 1.41 days in a nearly circular orbit tilted about 4 degrees to the planet's equator, an unusually large tilt for a regular moon. Rotation is synchronous, so the same hemisphere always faces Uranus.
Its density of about 1.18 g/cm3 points to a body composed of roughly equal parts water ice and silicate rock. The surface reflects about a third of the sunlight it receives and has a mean temperature of roughly 60 K, or about minus 213 degrees Celsius. Gerard P. Kuiper discovered Miranda on 16 February 1948 in photographs taken at the McDonald Observatory in Texas.
In keeping with the tradition for Uranus's moons, which take their names from Shakespeare and Alexander Pope, it was named after Prospero's daughter in The Tempest. Voyager 2 is the only spacecraft to have visited. During its Uranus encounter on 24 January 1986 it passed about 28,260 km from Miranda, closer than to any other moon of Uranus, though only the southern hemisphere was sunlit and imaged. The pictures revealed a startlingly varied surface: three large, sharply bounded regions of ridges and grooves called coronae (Arden, Elsinore and Inverness), set among older cratered terrain, along with deep fault canyons up to 12 times deeper than the Grand Canyon.
Verona Rupes is a scarp estimated at 5 to 10 km high, often described as the tallest known cliff in the solar system; NASA notes that a dropped rock would take a full 10 minutes to reach its foot. A popular claim holds that Miranda was smashed apart and reassembled. Most planetary scientists now favour a different explanation: internal heating from past tidal interactions with Uranus and Ariel or Umbriel drove upwelling that reshaped the surface from within. No mission has returned since 1986, and Uranus remains a high priority for a future orbiter.
Did you know?
- Verona Rupes may be the tallest cliff in the solar system, at 5 to 10 km high, and a rock dropped from its top would fall for about 10 minutes.
- Voyager 2 passed closer to Miranda than to any other moon of Uranus, only 28,260 km away.
- Only half of Miranda has ever been photographed close up. The northern half was in darkness when Voyager 2 flew past in 1986.
Neighbours around Uranus
- Titania
- Oberon
- Umbriel
- Ariel
- Puck
- Sycorax
- Portia
- Juliet
- Belinda
- Cressida
Questions children ask
Why does Miranda look like it was put together from different pieces?
Its surface mixes old cratered ground with three huge patches of ridges and grooves called coronae. Scientists think heat inside Miranda, caused by tugging from Uranus and its other moons, pushed warm ice upwards and reshaped parts of the surface.
Was Miranda really smashed apart and rebuilt?
That idea was popular after Voyager 2's visit, but most scientists now think it is unlikely. The strange patches are better explained by warm ice rising from inside the moon, a bit like slow-moving lava, rather than by a giant collision.
How tall is the cliff on Miranda?
Verona Rupes is estimated at 5 to 10 km high, which may make it the tallest cliff in the solar system. Because Miranda's gravity is so weak, NASA says a rock dropped from the top would take a full 10 minutes to hit the bottom.
Has anyone sent a spacecraft to Miranda?
Yes, but only once. Voyager 2 flew past on 24 January 1986, about 28,260 km away, and took all the close-up pictures we have. No spacecraft has been back since, although scientists would very much like to send an orbiter to Uranus.
Quick quiz
Three questions for space cadets. Nothing is recorded.
- Which planet does Miranda orbit?
- Which spacecraft is the only one to have flown past Miranda?
- About how long does Miranda take to orbit Uranus once?
Titania
Mimas
Enceladus