Lords of the rings

Abstract

Four hundred years of observations, from Galileo Galilei to the Voyager and Cassini missions, allow comparative analysis of the ring systems surrounding the outer planets. Although their extension and composition significantly differs from planet to planet, celestial mechanics represents the common driving force for explaining their present appearance. Traditional and exotic commensurable motions among ring particles, satellites and moonlets are frequently found, with intriguing consequences on the stability and confinement of the rings. Their dynamics can be studied by means of three-, four- and N-body subsystems, thus representing the ‘dream come true’ for celestial mechanics.