Why does Saturn have rings?

Saturn has rings because bits of ice and stone were pulled into orbit and spread around the planet instead of becoming one moon. Close to Saturn, gravity tugs harder on the near side than the far side, so fragile objects can break apart inside the Roche limit.

Those pieces keep circling because they are moving sideways very fast, the way a thrown ball would keep missing the ground if Earth curved away beneath it. The rings look smooth from far away, but up close they are countless icy scraps sharing a wide, thin track.