None of the moons in our solar system possess rings today. But a new study indicates that such rings, if created, could remain stable for a million years, even while being gravitationally pulled by other solar system objects. The findings deepen the mystery of why these satellites are now ring-free.
Rings surround many members of our planetary family. Saturn is perhaps the best-known example, swathed by eight main rings made of thousands of smaller ringlets, but the other three outer planets also possess rings, the Voyager space missions revealed. Composed of chunks of ice and rocks of varying sizes, these ring systems are maintained by small shepherding moons, whose gravitational forces tug the chunks and tweak their positions.
