Ring systems are collections of particles, ice, and rock that orbit around a planet. They can vary in size and composition, often forming from debris that was unable to coalesce into a moon. The most famous example is the Saturn ring system, which is composed of countless small particles that range from tiny grains to large boulders. Other planets, such as Jupiter, Uranus, and Neptune, also have ring systems, though they are less prominent than Saturn's. These rings can be made up of different materials, including dust and ice, and their structures can change over time due to gravitational interactions and collisions.