Oberon is the second largest moon of Uranus. Discovered in 1787, little was known about this moon until Voyager 2 passed it during its flyby of Uranus in January 1986. Oberon is heavily cratered — similar to Umbriel — especially when compared to three other moons of Uranus: Ariel, Titania and Miranda. Like all of Uranus’ large moons, Oberon is composed of roughly half ice and half rock. Oberon has at least one large mountain that rises about 6 km off the surface.
Oberon was discovered in January 1787 by William Herschel.
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PLANETARY FORMATION EVIDENT
“Oberon, the outermost satellite, is the second largest moon in the Uranium system. Its surface is dominated by large (50 to 100 kilometers) impact craters, some which exhibit radial patterns of bright ejecta. Some linear and curved scarps appear to be faults. Several very dark patches are found on Oberon, particularly on the floors of large craters. These areas may represent the extrusion of slushy material onto the surface from the interior following the period of heavy impact cratering, perhaps similar to the dark terrain on Saturn’s moon, Iapetus.”
The Compact NASA Atlas of the Solar System by Ronald Greeley and Raymond Batson