Moons appear and disappear; rings appear and disappear.

The new discoveries demonstrate that Uranus has a youthful and dynamic system of rings and moons.

Long-term changes to the system include collisions and crossing ring systems.

We don't think that is at all coincidental.

This appears to be a random or chaotic process, where there is a continual exchange of energy and angular momentum between the moons.

Now we're realizing that planetary systems are continually evolving. They change at a slower rate as they get older, but they continue to change.