Uranus V
One might have thought that Nature lived hard by and was brewing on a large scale. -Dickens
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 km. 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 km. 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 may 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 appearence can be explained by theories, but the real reason is still unknown.
Given Miranda's small size and low temperature (-335° F or -187° C), 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.
Discovered by ................................. Gerard Kuiper Date of discovery ...................................... 1948 Mass (kg) .......................................... 6.33e+19 Mass (Earth = 1) ................................. 1.0592e-05 Equatorial radius (km) ................................ 235.8 Equatorial radius (Earth = 1) .................... 3.6971e-02 Mean density (gm/cm^3) ................................. 1.15 Mean distance from Uranus (km) ...................... 129,780 Rotational period (days) ........................... 1.413479 Orbital period (days) .............................. 1.413479 Mean orbital velocity (km/sec) ......................... 6.68 Orbital eccentricity ................................. 0.0027 Orbital inclination .................................... 4.22° Escape velocity (km/sec) .............................. 0.189 Visual geometric albedo ................................ 0.27 Mean surface temperature ............................. -187°C Magnitude (Vo) ......................................... 16.3
Animation of Miranda
Miranda
(GIF, 145K)
Uranus' moon Miranda is shown in a computer-assembled mosaic of
images obtained Jan. 24, 1986, by the
Voyager 2 spacecraft.
Miranda is the innermost and smallest of the five major Uranian
satellites, just 480 kilometers (about 300 miles) in diameter.
This image is a full-disc, south-polar
view of the moon showing the varying geologic provinces of Miranda.
Miranda's surface consists of two major strikingly different
types of terrain. One is an old, heavily cratered, rolling
terrain with relatively uniform albedo,
or reflectivity. The
other is a young, complex terrain characterized by sets of bright
and dark bands, scarps
and ridges. These are features found in the
ovoid
regions at right and left and in the distinctive chevron
feature below and right of center.
(Courtesy NASA/JPL).
The Chevron
(GIF, 545K)
This view of Miranda shows details as small as
600 meters across. It was acquired by Voyager 2 on January 24, 1986.
This is a close-up view of the chevron which shows the light and
dark grooves with its sharp boundaries. The upper right shows a region
of uniformly dark grooved terrain. The area shown is about 150 km on
a side.
(Credit: Calvin J. Hamilton, Los Alamos National Laboratory)
Uranus
Puck
Ariel
