The Orbital Resonance Amongst the Galilean Satellites of Jupiter

Abstract

The resonance amongst three of the Galilean satellites is described in a way intended to demonstrate the similarities it has to the normal two-satellite resonance. The hypothesis that the resonance was formed by the action of tidal forces is discussed. The problem is too complicated to reach any firm conclusions, but the tidal hypothesis does not seem to be a satisfactory explanation. The inner three satellites of Uranus have an approximate relationship amongst their mean motions similar to that of the Galilean satellites. The type of libration possible in this system is briefly discussed.