Saturn's rings are made mostly of countless chunks of ice and rock.

The longer version

Ring particles orbit Saturn independently, each following its own path under the planet's gravity, which is why the rings look smooth from a distance but resolve into countless separate bodies up close. Most pieces are water ice, ranging from fine grains to house sized chunks, mixed with darker rocky material. Sunlight striking the ice makes them bright.

The rings are broad yet astonishingly thin, and they sit inside a region where tidal forces would break apart a larger moon. Shepherd moons help keep some edges sharp. Over long spans the material is slowly rearranged, and icy particles are continually resupplied by impacts and breakup events.

Where this entry sits

The night sky looks calm, yet almost everything up there is moving, burning, or slowly changing. These facts cover planets, stars, the Moon, gravity, black holes, comets, and the story of how people began exploring beyond Earth. The full list sits on the Space and Sky page, where every entry is listed in order.