Saturn: Structures & Vocabulary

Saturn is a hydrogen-helium gas giant distinguished by its extensive ring system, low average density, rapid rotation, layered atmosphere, and large family of moons. Its visible cloud tops hide a deep fluid interior rather than a solid surface.

Saturn radiates substantial internal heat from slow cooling and processes including helium separation within the deep interior. Rapid rotation and convection help organize zonal winds and polar features such as the north-polar hexagon. In the rings, collisions flatten particles into a thin disk while resonances and small moons create gaps, waves, and sharp edges.

Cassini measured Saturn's atmosphere, gravity, magnetic field, rings, and moons over many years. Stellar and radio occultations reveal ring structure, while spacecraft imaging shows density waves and moon interactions. Infrared measurements demonstrate that Saturn emits more heat than it receives from sunlight.

Saturn's atmosphere overlies molecular and metallic hydrogen regions with heavier material concentrated inward. The rings are made mostly of water-ice particles spanning a wide range of sizes. Gaps, waves, narrow ringlets, and embedded moonlets reveal continual gravitational sculpting.