Late origin of the Saturn system

► We propose that Saturn originally had a family of Galilean-like satellites that collided and merged. ► Simulations of these mergers result in the formation of escaping, clump-forming, ice-rich spiral arms. ► Clump sizes and compositions in these simulations resemble Saturn's middle-sized moons. ► Moon-forming collisions would have occurred over a wide range of orbital distances from Saturn. ► Late collisions triggered by Solar System upheaval could explain extraordinary aspects of the Saturn system.