In addition to the five satellites and nine rings known prior to 1986, the "Voyager" mission also confirmed the existence on Uranus of ten other mini-moons and a still imprecise number of rings. Many years will be needed to study all this information. The fact is that the rings of Uranus reflect only 5% of the solar radiation, in other words they are very dark. Their color is similar to the mysterious dark hemisphere of Iapetus and is probably due to the presence of hydrocarbons in the ice particles that form the rings. The most external ring, called "epsilon", is one hundred kilometers wide. It is watched over by two of the moons discovered by Voyager, 1986U7 and 1986U8, which behave like the "shepherd moons" already identified by the probe among the rings of Saturn: their job is to "hold" the particles together that form the rings. The eight other known rings have a more circular shape and their width varies from 60 to 5-6 kilometers: all are made of very small particles and most of them are no larger than a few centimeters. But, mixed with these, Voyager also identified many other much thinner rings, whose width does not exceed 50-100 meters, and a disk of microscopic material that extends from the innermost ring to the surface of the planet with a width of about 3 000 kilometers. The other eight mini-moons discovered by Voyager orbit in the region between an inner satellite, Miranda, and the epsilon ring: with their diameters between the 15 kilometers of 1986U7 and the 130 kilometers of 1986U1, they are really very small compared to the larger satellites and probably have an irregular shape. Perhaps future studies may be able to determine if they have a different origin, but the greatest interest is certainly focused on the five known satellites, whose characteristics have already been displayed in all their splendor by the Voyager television cameras.
In addition to the five satellites and nine rings known prior to 1986, the "Voyager" mission also confirmed the existence on Uranus of ten other mini-moons and a still imprecise number of rings. Many years will be needed to study all this information. The fact is that the rings of Uranus reflect only 5% of the solar radiation, in other words they are very dark. Their color is similar to the mysterious dark hemisphere of Iapetus and is probably due to the presence of hydrocarbons in the ice particles that form the rings. The most external ring, called "epsilon", is one hundred kilometers wide. It is watched over by two of the moons discovered by Voyager, 1986U7 and 1986U8, which behave like the "shepherd moons" already identified by the probe among the rings of Saturn: their job is to "hold" the particles together that form the rings. The eight other known rings have a more circular shape and their width varies from 60 to 5-6 kilometers: all are made of very small particles and most of them are no larger than a few centimeters. But, mixed with these, Voyager also identified many other much thinner rings, whose width does not exceed 50-100 meters, and a disk of microscopic material that extends from the innermost ring to the surface of the planet with a width of about 3 000 kilometers. The other eight mini-moons discovered by Voyager orbit in the region between an inner satellite, Miranda, and the epsilon ring: with their diameters between the 15 kilometers of 1986U7 and the 130 kilometers of 1986U1, they are really very small compared to the larger satellites and probably have an irregular shape. Perhaps future studies may be able to determine if they have a different origin, but the greatest interest is certainly focused on the five known satellites, whose characteristics have already been displayed in all their splendor by the Voyager television cameras.
