Uranus's moons shouldn't exist.
Simulations of the giant planet instability — the period when the outer planets' orbits rearranged — show that the survival probability for both Jupiter's and Uranus's major satellite systems is less than 15% (arXiv:2603.21750). Out of 122 simulated scenarios, exactly one preserved both systems through the same instability event.
The destruction is mechanical. When Uranus encounters another ice giant within 0.02 AU, or a gas giant within 0.1 AU, the tidal perturbation strips or collides the satellites. The encounters during instability are close enough and frequent enough that survival is the exception. The current moons of Uranus are either extraordinarily lucky survivors or — more likely — second-generation objects: debris from destroyed predecessors that re-accreted after the instability ended.
This makes Uranus's moons twice-shattered. The first destruction was the giant impact that tilted Uranus 98 degrees — an event violent enough to vaporize any pre-existing satellite system. The moons we see formed from the impact debris disk. Then the giant planet instability likely destroyed those moons too, and the current moons formed from that debris. The objects orbiting Uranus today may be third-generation — grandchildren of the original system.
An unexpected asymmetry: Jupiter's moons survive better in scenarios with two smaller ice giants (less massive encounters), while Uranus's survive better with larger additional planets (which migrate outward faster and reduce the instability duration). The optimal conditions for one system are suboptimal for the other. The Solar System's architecture had to thread a narrow needle to preserve both.
The survival of what we see required improbable luck or regeneration — and regeneration means the moons carry no memory of the Solar System's original configuration. They're evidence of aftermath, not formation.