Ring system

A ring system is a disc or torus orbiting an astronomical object that is composed of numerous solid bodies such as dust particles, meteoroids, minor planets, moonlets, or stellar objects. Ring systems are best known as planetary rings, common components of satellite systems around giant planets such as the rings of Saturn, or circumplanetary disks. But they can also be galactic rings and circumstellar discs, belts of minor planets, such as the asteroid belt or Kuiper belt, or rings of interplanetary dust, such as around the Sun at distances of Mercury, Venus, and Earth, in mean motion resonance with these planets. Evidence suggests that ring systems may also be found around other types of astronomical objects, including moons and brown dwarfs. In the Solar System, all four giant planets (Jupiter, Saturn, Uranus, and Neptune) have ring systems, but Saturn's ring system is the biggest and the most visible one out of the four. Ring systems around minor planets have also been discovered via occultations. Some studies even theorize that the Earth may have had a ring system during the mid-late Ordovician period.