Why Saturn should be the only planet to possess such a system of rings has never been explained in an entirely satisfactory manner. There is an interesting law known as "Roche's Law," however, named from its investigator, that states that no satellite of a planet can exist intact with 2.44 times the radius of the planet. This limit is spoken of as "Roche's Limit" and applying it to the planet Saturn we find that the rings of Saturn fall within this limit. It does not necessarily follow from this that the minute particles of which the rings are composed are the shattered remains of one small satellite, but rather that they are the material from which a satellite might have been formed were it not so close to the planet. Within "Roche's Limit" the mutual attraction of the various particles for each other that would tend eventually to gather them into one body is overcome by tidal forces that arise from such close proximity to the huge planet. The stress and strain of such forces is so great that no grouping of particles can take place. This explains, possibly, why the rings continue to exist in their present condition. The total quantity of matter in the rings is known to be very small, for it does not disturb the motions of any of the nearer and smaller satellites, though tiny Mimas, six hundred miles in diameter, is only thirty-one thousand miles beyond the outer edge of the outer ring.