Impacts written over impacts.
Oberon is Uranus’s second-largest moon. Its densely cratered surface preserves a long impact history, with less obvious resurfacing than on several neighboring moons. Voyager 2 also revealed a mountain rising about six kilometers above the surrounding surface, a striking landmark on this distant world.
Beyond the other major moons.
Oberon is the outermost of Uranus’s five major moons. Its nearly circular orbit lies about 583,511 kilometers from the planet’s center, and one circuit takes about 13.463 Earth days. Smaller, irregular moons travel much farther out; Oberon is not the edge of the entire satellite system.
Old terrain does not settle what lies below.
Thermal models allow an ocean beneath Oberon’s icy exterior. Heat retained inside the moon, together with dissolved substances that lower water’s freezing point, could preserve liquid. This remains a model-based possibility, not a confirmed ocean or evidence of life.
A brief encounter, an incomplete map.
Voyager 2 passed the Uranian system in 1986, providing the close-up images behind much of our picture of Oberon. The northern hemispheres of the major moons were largely unobserved during that encounter. Another spacecraft could examine the missing terrain and test ideas about their interiors.
