Sun & planets · Space Codex
Saturn
The only planet less dense than water, wrapped in rings that span 282,000 km yet are typically about 10 m thick.
Ringed gas giant
At a glance
Key points
Its moons include Titan, with a thick atmosphere, and Enceladus, which sprays its ocean into space.
- The only planet less dense than water
- 293 known moons, more than all other planets combined
- A hexagonal jet stream wider than two Earths circles its north pole
Interior
A dense core of rock and metal sits under layers of liquid metallic hydrogen and then liquid molecular hydrogen. Saturn radiates more heat than it receives from the Sun, partly because helium rain slowly sinks through the interior.
Rings
The rings are billions of water-ice fragments, from dust to house-sized blocks. They span 282,000 km but are typically only about 10 m thick. The Cassini Division, a 4,700 km gap between the A and B rings, is swept clear by a resonance with the moon Mimas.
Atmosphere and weather
Equatorial winds reach about 500 m/s. A six-sided jet stream about 30,000 km across circles the north pole, and in September 2026 a study of Hubble images reported a ten-sided wave around the south pole.
Exploration
Pioneer 11 and both Voyagers flew past; Cassini orbited from 2004 to 2017 and dropped the Huygens probe onto Titan in 2005. NASA's Dragonfly rotorcraft is due to launch no earlier than July 2028 for Titan.
What we still don't know
How old the rings are, how long Saturn's day is at depth, and how the polar hexagon has stayed stable for decades.
Moons
The 7 major moons of Saturn in the Codex, each with its own sourced entry.
Missions
- 1973–1995
Pioneer 11
NASACompletedFirst Saturn flyby (1979).
- 1977–
Jupiter 1979, Saturn 1980; interstellar space since 25 Aug 2012.
- 1977–
The only spacecraft to visit Uranus (1986) and Neptune (1989); interstellar since 5 Nov 2018.
- 1997–2017
Cassini–Huygens
NASA / ESA / ASICompletedOrbited Saturn 2004–2017 and ended by diving into the planet.
- 14 Jan 2005
Huygens probe
ESACompletedLanded on Titan: the most distant landing ever made.
- Launch NET Jul 2028
Nuclear-powered rotorcraft; arrives at Titan around 2034 for a 3.3-year mission.
First-hand · our 3D model
How we render it
Saturn's rings span 1.12 to 2.27 Saturn radii, the NSSDC values. They are shaded as a single-scattering slab rather than a flat picture: the dense B ring darkens when you see its unlit face, while the dusty C ring and the Cassini Division brighten when backlit. The globe casts its shadow across the rings, and the rings cast theirs onto the globe.
The globe itself is the flattest in the Solar System, with a polar radius 0.902 of the equatorial, and is tilted 26.7°. A faint hint of the north-polar hexagon, the standing jet-stream wave near 78°N, turns with the planet. Seven major moons orbit outside the rings.
Sizes and distances in the model are not to scale, so every world can be seen up close. Colour maps are derived from NASA mission imagery via Solar System Scope (CC BY 4.0). The first frame uses light startup maps; higher-resolution maps stream in after the scene is on screen, decoded off the main thread so the page stays responsive.
Related entries
Sources
- JPL Solar System Dynamics: planetary physical parameters (opens in a new tab)
- NASA NSSDC Planetary Fact Sheet (opens in a new tab)
- NASA NSSDC Saturn Fact Sheet (opens in a new tab)
- NASA Science: Saturn facts (opens in a new tab)
- NASA Science: Saturn moons (opens in a new tab)
Last reviewed against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.