Saturn's system 300 million years ago resembled a crowded dance floor. The most massive moon, Titan, began to migrate, and this movement threw its neighbors off balance. One moon crashed into Titan; the debris swirled into a vortex, gathering into Hyperion. Gravitational perturbations from the collision propagated inward, and the inner moons shattered into ice and dust — thus the rings were woven.
An unexpected step in this dance: the orbit of Iapetus tilted under the influence of that same moon before its demise. Computer simulations confirmed that this chain of events explains both the youth of the rings and the oddities of the moons.
The mass of the rings is no greater than an icy boulder the size of Mimas (400 km) — a modest outcome of a colossal collision.
The total mass of all Saturn's rings is roughly equal to an icy moon about 400 km in diameter – like Mimas.