Triton's gravity disrupted the planet's original moonsAncient disaster for Neptune's moons observedNew observations of some of Neptune's moons and rings are providing evidence of a catastrophe that occurred billions of years ago around the solar system's outermost planet in which a Pluto-sized interloper caused a celestial demolition derby. "The moons themselves are far too small and cold for that chemistry to have occurred in place, so the clay had to come from somewhere else - the deep interior of a much larger ancient world. Finding this material on Neptune's inner moons points to a catastrophic event in Neptune's past that destroyed those ancient worlds and exposed their deep interiors, with the small moons and rings we see today re-forming from that wreckage," said Davis, who worked on the study while at Caltech. After being captured, Triton's own gravitational forces stirred up Neptune's original moons and caused most of them to collide with each other. Neptune's current inner moons eventually formed from some of the resultant debris.