Page "Rings of Uranus" Paragraph 40

Since the rings of Uranus appear to be young, they must be continuously renewed by the collisional fragmentation of larger bodies.

The estimates show that the lifetime against collisional disruption of a moon with the size like that of Puck is a few billion years.

The lifetime of a smaller satellite is much shorter.

Therefore all current inner moons and rings can be products of disruption of several Puck-sized satellites during the last four and half billion years.

Every such disruption would have started a collisional cascade that quickly ground almost all large bodies into much smaller particles, including dust.

Eventually the majority of mass was lost, and particles survived only in positions that were stabilized by mutual resonances and shepherding.

The end product of such a disruptive evolution would be a system of narrow rings.

However, a few moonlets must still be embedded within the rings at present.

The maximum size of such moonlets is probably around 10 km.