Uranus: Moons: Miranda
Miranda [mih-RAN-dah] is not one of the larger satellites of Uranus; however, it was the one that was approached the closest by Voyager 2. This was not the satellite scientists would have chosen to get close to if they had a choice, but they had no choice. Voyager 2 had to fly close to the planet in order to get the boost it needed to go to Neptune. The resolution at which the larger satellites were photographed was around 2 to 3 kilometers (1.2 to 1.9 miles). On the other hand, details on the order of a few hundred meters can be seen on Miranda. Fortunately, Miranda turned out to be the most remarkable of all the satellites.
Miranda is a small satellite with a diameter of 470 kilometers (290 miles). Its surface is unlike anything in the solar system with features that are jumbled together in a haphazard fashion. Miranda consists of huge fault canyons as deep as 20 kilometers (12 miles), terraced layers and a mixture of old and young surfaces. The younger regions might have been produced by incomplete differentiation of the moon, a process in which upwelling of lighter material surfaced in limited areas. Alternatively, scientists believe that Miranda may have been shattered as many as five times during its evolution. After each shattering the moon would have reassembled from the remains of its former self with portions of the core exposed and portions of the surface buried. Miranda's appearance can be explained by theories, but the real reason is still unknown.
Given Miranda's small size and low temperature (-187 degrees C or -305 degrees F), the degree and diversity of the tectonic activity on this moon has surprised scientists. It is believed that an additional heat source such as tidal heating caused by the gravitational tug of Uranus must have been involved. In addition, some means must have mobilized the flow of icy material at low temperatures.
Miranda was named after the daughter of the magician Prospero in Shakespeare's play The Tempest.
This picture was constructed from images taken through the narrow-angle camera's green, violet and ultraviolet filters. It is the best color view of Miranda returned by Voyager. Miranda, just 480 km (300 mi) across, is the smallest of Uranus' five major satellites. Miranda's regional geologic provinces show very well in this view of the southern hemisphere, imaged at a resolution of 2.7 km (1.7 mi). The dark- and bright-banded region with its curvilinear traces covers about half of the image. Higher-resolution pictures taken later show many fault valleys and ridges parallel to these bands. Near the terminator (at right), another system of ridges and valleys abuts the banded terrain; many impact craters pockmark the surface in this region. The largest of these are about 30 km (20 mi) in diameter; many more lie in the range of 5 to 10 km (3 to 6 mi) in diameter.
