Abstract
In this work we describe some aspects of the dynamics of the mean-motion resonances. Emphasis to the case of resonances between regular satellites of the giant planets will be given, even so some aspects of the physics of the resonances in extra-solar planetary systems are also briefly treated. The role of the resonances in satellites systems is discussed through examples, showing how certain resonances, and its relations with the tidal dissipation effects, can be the key of the explanation of some phenomena still not explained in the Solar System. Amongst some examples we highlight the problem of the resurfacing of Enceladus, the existence of active volcanoes in Io, and the possible existence of the subsurface ocean in Europe. This work has as objective the divulgation of some topics in Celestial Mechanics and Planetary Sciences for an undergraduate public in exact sciences, as Astronomy and Physics, and not their detailed description.