Facts about Saturn, by the numbers

Updated October 19, 2026 · 5 min read

The essential facts about Saturn: it is the sixth planet from the Sun and the second largest, a hydrogen-and-helium gas giant 120,536 km wide with a mass of 95 Earths and a density below that of water. It orbits the Sun in 29.46 years at 1.43 billion km, spins in about 10 hours 33 minutes and has 274 confirmed moons and the most extensive ring system known.

Saturn data table

Size and structure

1. Saturn is the second-largest planet. Only Jupiter is bigger. Saturn's equatorial diameter is about 9.5 times Earth's, and its volume could contain around 764 Earths. More on the size and mass page.
2. It is the flattest planet. Its polar diameter is about 10% shorter than its equatorial diameter, a difference close to the width of the whole Earth, caused by its rapid spin.
3. Its average density is lower than water's. At 0.687 g/cm³, Saturn is the only planet less dense than liquid water, which has fuelled the cliché that it would float. The density page explains why that image is more misleading than it seems.
4. There is no surface. Saturn is gas on top, then liquid, then an electrically conducting metallic fluid deep inside. "Surface" values such as gravity are quoted at the altitude where pressure equals 1 bar, Earth's sea-level pressure.
5. Its core is fuzzy. Oscillations recorded in the rings suggest a diffuse core of rock, ice and hydrogen spread over about 60% of the planet's radius rather than a compact solid ball. See interior.
6. Gravity at cloud level is close to Earth's. At about 1.07 g on the equator, a person would weigh only slightly more at the 1-bar level than at home, although there would be nothing to stand on. Try the weight calculator.

Orbit and rotation

1. A year lasts 29.46 Earth years. Saturn has completed only about 14 orbits since Galileo first turned a telescope on it in 1610.
2. Sunlight is weak. At 9.54 AU, Saturn receives about 1% of the sunlight that reaches Earth.
3. A day lasts about 10 hours 33 minutes. This value, from Cassini measurements of waves in the rings published in 2019, replaced the Voyager-era 10 h 39 min. The story is told on the day length page.
4. Saturn has seasons. Its 26.73° tilt produces seasons of about 7.4 years. The equinoxes of August 2009 and May 2025 bracket a full northern spring and summer. See seasons.
5. It returns to opposition every 378 days. That is when Saturn is closest to Earth and brightest; the opposition dates page lists the next ones.
6. Light takes 67 to 92 minutes to arrive. The exact delay depends on the changing distance from Earth.

Atmosphere and weather

1. The atmosphere is mostly hydrogen. About 96% hydrogen and 3% helium by volume, with traces of methane, ammonia, ethane and phosphine. See atmosphere.
2. Winds are among the fastest in the solar system. The equatorial jet reaches about 1,800 km/h, more than four times the strongest winds measured on Earth.
3. Its color comes from haze. A layer of photochemical haze above the ammonia clouds gives Saturn its muted butterscotch hue; the reasons are on the color page.
4. A hexagon crowns the north pole. The six-sided jet stream is about 29,000 km across, more than twice Earth's diameter. See hexagon.
5. Giant storms come back roughly every 30 years. Great White Spots were recorded in 1876, 1933, 1990 and 2010, among other years. See storms.
6. Saturn emits more energy than it receives. It radiates about 2.5 times the energy it absorbs from the Sun, a surplus thought to come largely from helium rain deep inside.

Magnetism, rings and moons

1. Its magnetic field is almost perfectly aligned with its spin axis. Cassini's final orbits found a tilt of less than 0.01°, a puzzle for dynamo theory. See magnetosphere and auroras.
2. The rings are huge but razor-thin. The main rings span about 140,000 km from Saturn's center, yet are typically only about 10 metres thick. See rings.
3. The rings are mostly water ice. More than 95% of their mass is ice, with a total mass of about 1.5 × 10¹⁹ kg, roughly 40% of the moon Mimas.
4. Saturn has 274 confirmed moons, more than any other planet, after 128 new ones were announced in March 2025. See how many moons.
5. Titan is bigger than Mercury. Saturn's largest moon is 5,150 km across and has a thick nitrogen atmosphere. See Titan.
6. Four spacecraft have visited. Pioneer 11 in 1979, Voyager 1 in 1980, Voyager 2 in 1981 and Cassini, which orbited from 2004 until its deliberate plunge on 15 September 2017. See exploration.
7. It is named after a Roman god. Saturn was the Roman god of agriculture and time, linked to the Greek Cronus; the name and symbol page traces the history of the glyph.

Sources

• NASA NSSDCA: Saturn Fact Sheet
• NASA Science: Saturn facts
• Mankovich, C. et al. (2019), "Cassini Ring Seismology as a Probe of Saturn's Interior", The Astrophysical Journal 871:1
• Iess, L. et al. (2019), "Measurement and implications of Saturn's gravity field and ring mass", Science 364