Miranda (moon)
Encyclopedia : M : MI : MIR : Miranda (moon)
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| Discovery | |||||||
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| Discovered by | Gerard P. Kuiper | ||||||
| Discovered in | February 16, 1948 | ||||||
| Orbital characteristics | |||||||
| Semi-major axis | 129,390 km | ||||||
| Mean radius | 129,872 km | ||||||
| Eccentricity | 0.0013 | ||||||
| Orbital period | 1.413479 d | ||||||
| Inclination | 4.232° (to Uranus' equator) | ||||||
| Is a satellite of | Uranus | ||||||
| Physical characteristics | |||||||
| Mean diameter | 471.6 km (480×468.4×465.8 km) (0.03697 Earths) | ||||||
| Surface area | 2,790,000 km2 | ||||||
| Volume | 54,835,000 km3 | ||||||
| Mass | kg (1.103 Earths)> | ||||||
| Mean density | 1.20 g/cm3 | ||||||
| Surface gravity | 0.079 m/s2 | ||||||
| Escape velocity | 0.19 km/s | ||||||
| Rotation period | synchronous | ||||||
| Axial tilt | zero | ||||||
| Albedo | 0.32 | ||||||
| Surface temp. |
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| Atmospheric pressure | 0 kPa | ||||||
It was discovered by Gerard Kuiper on 1948-02-16 at McDonald Observatory. It is named after Prospero's daughter in William Shakespeare's play The Tempest. It is also designated Uranus V.
So far the only close-up images of Miranda are from the Voyager 2 probe, which made observations of the moon during its Uranus flyby in January, 1986. During the flyby the southern hemisphere of the moon was pointed towards the Sun so only that part was studied. It was a fortunate coincidence that the moon passed by at the closest distance by Voyager 2 turned out to be the geologically most active body in the Uranus system.
Physical characteristics
Miranda's surface may be mostly water ice, with the low density body being made of silicate rock and organic compounds. Miranda's surface is criss-crossed by huge canyons up to 10 kilometers (6 miles) deep, with patchwork regions of broken terrain indicating intense geological activity in the moon's past. Large grooved structures, called coronae, may be the result of upwelling warm ice. It is thought that this activity was powered by tidal forces from Uranus, possibly due to past resonance with other uranian moons. Another theory, now considered less likely, suggests that a previous incarnation of Miranda was struck by a massive object that shattered the moon soon after its formation. Fragments then resettled into different positions forming the current strange pattern.
Miranda's orbital inclination (4.34°) is unusually high for a body so close to the planet. At some time in the past, it is possible that it was in a 3:1 orbital resonance with Umbriel. Resulting tidal friction may also have caused warming within the moon and thus be the culprit of the geological activity.
Scientists recognize the following geological features on Miranda:
- Craters
- Coronae (large ovoid features)
- Regiones (geological regions)
- Rupes (scarps)
- Sulci (parallel grooves)
See also
External links
- [Kuiper, Gerard P., "The fifth satellite of Uranus", PASP 61 (1949) 129]
- [The Nine Planets – Miranda]
- [Views of the Solar System – Miranda, A Moon of Uranus]
Uranus (satellites) [http://encycl.opentopia.com/ edit] |
|---|
| Cordelia | Ophelia | Bianca | Cressida | Desdemona | Juliet | Portia | Rosalind | Cupid |
| Belinda | Perdita | Puck | Mab | Miranda | Ariel | Umbriel | Titania | Oberon | Francisco |
| Caliban | Stephano | Trinculo | Sycorax | Margaret | Prospero | Setebos | Ferdinand |
| See also: | Rings of Uranus |
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