After a cataclysmic impact with a large celestial body, the major moon Oberon formed in orbit around the ice giant Uranus from an accretion disc or sub nebula. This formation would either have collapsed under its own gravity forming Uranus’s five major moons in the process, or the five major moons grew in size from small moons as they collected material while orbiting through these structures, similar to moons in Saturn’s rings creating gaps as they orbit.
Amongst the craters on Oberon sink many chasms and valleys, the deepest of these are lined with an unknown dark material. These geological features are usually formed through movement of tectonic plates above a hot liquid mantle, so why does a small moon orbit an ice-giant in deep space show evidence of this? One theory suggests that radioisotope decay within the rock coupled with remnant primordial heat, generated enough intensity to cause the mantle zone to expand and crack the cooling surface layer into plates. Though without further study the cause of this mysterious geological activity remains unexplained.
What excites me the most about Oberon are the possibilities that it encourages, the chasms and craters tell a heated history while the resident ice giant suggests something stranger beneath the surface. This small half-ice half-rock moon is an example of what we do not know and what there is to learn in these far out places.
A probe or rover to Oberon would need to be capable of measuring subsurface composition, magnetospheres and geology in order to maximise the scientific output of this mission. Because under the right kind of observation I believe Uranus and its moons could be a massive scientific sneak-peek into the formation of the solar system, Earth and geological activity through the perspective of these deep space bodies.