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Object profile · SATURN

Saturn

Hydrogen-rich gas giant

A low-density giant wrapped in weather and a broad system of icy rings, with no solid surface beneath its visible clouds.

Atlas data reviewed
Editorial stage
Published
Visibility
Public
Saturn and its rings seen as a thin sunlit crescent against black space in a Cassini mosaic.Direct observation
Cassini's natural-colour farewell mosaic of Saturn and its rings, assembled from wide-angle images.

Processed spacecraft mosaic, not one exposure. Multiple filtered frames were assembled; ring and planet sizes share the same view, but this crop is not a Solar System distance scale.

NASA/JPL-Caltech/Space Science Institute ↗
Vastward explanation

What this world is

Saturn is more than its rings. The pale globe is a deep hydrogen-helium world that becomes denser with depth instead of ending at solid ground. Countless orbiting ice and rock particles make the rings look continuous from afar.

Why it looks this way now

Saturn still leaks heat left from formation and from helium settling deeper inside. Fast rotation flattens the planet and organizes clouds into bands, while gravity and resonances sculpt gaps and waves in the rings.

02

Where it sits

Saturn is the sixth planet from the Sun, averaging about 1.4 billion kilometres or 9.5 astronomical units away. One orbit lasts about 29.4 Earth years.

How to read this mapPlanetary order · 6 of 8 from the Sun

Swipe sideways to inspect the full map

Planetary order · 6 of 8 from the SunEight compressed orbits surround the Sun. Orbit 6, belonging to Saturn, is highlighted in blue, with all planets ordered below.SunPosition 6 from the SunSaturnMercuryVenusEarthMarsJupiterSaturnUranusNeptune
Blue marks the current planet

The blue orbit, marker and name locate Saturn without implying its live position today.

Neighboring worlds provide order context

Jupiter is immediately inside; Uranus is immediately outside. The lower sequence preserves all eight positions.

The figure preserves the eight-planet order and orbital hierarchy; distances, orbit spacing, body sizes and marker positions are compressed for teaching rather than shown live.
03

Read the numbers

Reference values retain their units, context, evidence state and published uncertainty.

Physical measurements

Mean radiusglobal mean
58,232kmCalculated measurementAbout 9.1 Earth radii.

An atmospheric reference radius, not a boundary of solid ground.

Published uncertainty: ± 6 km

JPL tabulated uncertainty at an adopted atmospheric reference level; Saturn has no solid surface.

Massglobal mean
5.68317E26kgCalculated measurementAbout 95 Earth masses.

Moon and spacecraft motions reveal the total gravitational mass.

Published uncertainty: ± 2.6E22 kg

Converted from the uncertainty in the JPL 10^24 kilogram table.

Mean densityglobal mean
0.6871g/cm³Calculated measurementLower than liquid water's density.

The popular floating comparison ignores that no ocean could hold Saturn and gravity compresses it.

Published uncertainty: ± 0.0002 g/cm³

Calculated from adopted mass and volume.

Reference gravityequatorial reference
10.44m/s²Calculated measurementAbout 1.06 times Earth's at the reference level.

Large radius offsets much of the effect of Saturn's larger mass.

No uncertainty published in this source table

Reference equatorial gravity at an adopted atmospheric level, not gravity on solid ground.

Temperaturevisible cloud level
-140°CCalculated measurementA representative value near the visible cloud level.

Temperature rises deeper down and varies with season and latitude.

Approximate value

Representative one-bar cloud-level temperature; altitude, latitude and season matter.

Temperaturedeep interior model
11,700°CScientific modelA model value roughly twice the Sun's visible-surface temperature.

No instrument has entered Saturn's centre.

Approximate value

NASA's approximate modeled central temperature, not a direct thermometer measurement.

Orbit and rotation

Average distancerelative to the Sun
1,400,000,000kmCalculated measurementAbout 9.5 times Earth's average solar distance.

Sunlight there is about one ninetieth as intense per square metre.

Approximate value

Rounded average distance, about 9.5 astronomical units.

Rotation periodrelative to distant stars
0.44401Earth daysCalculated measurementAbout 10 hours 39 minutes.

Clouds rotate differentially and magnetic estimates are not perfectly simple.

No uncertainty published in this source table

Adopted bulk rotation period; Saturn's visible atmosphere rotates at different speeds by latitude.

Orbital periodrelative to the Sun
29.447498Earth yearsCalculated measurementA Saturn season lasts more than seven Earth years.

One full year spans about 29.4 Earth years.

No uncertainty published in this source table

Sidereal orbital period from astrometry and dynamical ephemerides.

04

Atmosphere and inside

Atmosphere

Hydrogen dominates, followed by helium and trace methane, ammonia, water and other species. Ammonia clouds help form the visible upper deck, with deeper condensate layers inferred below.

HydrogenRelative abundance described; exact fraction not listed
HeliumRelative abundance described; exact fraction not listed
Methane, ammonia, water and trace speciesRelative abundance described; exact fraction not listed

Surface and interior

There is no solid surface. Clouds and rings are observed directly; metallic hydrogen and a diffuse heavy-element core are pressure-and-composition models tested against gravity, magnetic and ring-wave data.

No solid surface: layers transition gradually as pressure and temperature rise.

  1. 1
    Diffuse heavy-element core

    Cassini gravity and ring-seismology studies favour a broad central region mixed with hydrogen and helium, not a sharply bounded rock ball.

    Scientific model
  2. 2
    Metallic hydrogen layer

    Extreme pressure is modeled to turn hydrogen into an electrically conducting fluid that helps generate the magnetic field.

    Scientific model
  3. 3
    Molecular hydrogen envelope

    Hydrogen and helium compress gradually from gas-like clouds into dense fluid, with no solid landing surface.

    Scientific model
  4. 4
    Cloud decks and ring system

    Spacecraft directly image atmospheric bands, storms and icy rings. The rings orbit outside Saturn and are not an interior layer.

    Direct observation
05

How we know

Images define clouds, shape and rings. Radio tracking maps gravity and occultations. Infrared spectra retrieve temperatures and gases. Ring waves add an unusual probe of internal oscillations.

  1. 01

    Multifilter spacecraft imaging

    Cassini cameras mapped clouds, rings, shadows and the apparent limb across wavelengths and viewing angles.

    Where this method stops

    Colour composites combine filters and exposures; clouds mark pressure levels, not solid terrain.

    Direct observation
  2. 02

    Radio tracking, occultations and ring waves

    Doppler tracking measures gravity; radio occultations probe atmosphere and rings; waves in the rings can carry signatures of Saturn's oscillations.

    Where this method stops

    Recovering an interior requires models of rotation, winds, ring dynamics and spacecraft forces.

    Calculated measurement
  3. 03

    Infrared spectroscopy

    Thermal spectra reveal temperature, gases, clouds and seasonal change at different atmospheric depths.

    Where this method stops

    Spectra sense broad weighting layers and require radiative-transfer models to retrieve physical conditions.

    Calculated measurement
  4. 04

    Interior model inversion

    Gravity, shape, magnetic and ring-wave constraints are compared with candidate pressure, composition and flow models.

    Where this method stops

    Several interiors can fit the same global data; core boundaries and helium separation remain uncertain.

    Scientific model
06

Evidence key

Direct observation
An instrument or sample recorded the phenomenon, with processing still disclosed.
Calculated measurement
Observed motion or signal is converted into a physical quantity using equations and reference constants.
Scientific model
A tested interpretation that fits observations but is not directly imaged or sampled.
Vastward explanation
Original beginner-facing synthesis, traceable to the source records but not itself a measurement.
Artist visualization
An interpretive image, not observational evidence.
07

Missions and instruments

Completed

Cassini-Huygens

Orbited Saturn for 13 years, mapping the planet, rings, magnetosphere and moons with remote sensing and radio science.

Official mission ↗
Instruments
  • Imaging Science SubsystemVisible and near-infrared images of atmosphere, rings, moons and limb geometry.
  • Radio Science SubsystemDoppler motion, atmospheric and ring occultations, gravity harmonics and ring particle structure.
  • Composite Infrared SpectrometerThermal spectra used to retrieve atmospheric temperature and composition.
08

Official source trail

Links below are the exact records used for this profile. Access dates are retained with the content.

  1. 01

    NASA Jet Propulsion Laboratory, Solar System Dynamics · dataset

    Planetary Physical Parameters

    Source updated
    No source update date published
    Access checked
    2026-07-30
    Open official source ↗
  2. 02

    NASA Science · official-page

    Saturn Facts

    Source updated
    2025-05-22
    Access checked
    2026-07-30
    Open official source ↗
  3. 03

    NASA/JPL-Caltech/Space Science Institute · image

    Saturn Farewell

    Source updated
    2025-05-22
    Access checked
    2026-07-30
    Open official source ↗
  4. 04

    NASA Science · official-page

    Cassini-Huygens

    Source updated
    No source update date published
    Access checked
    2026-07-30
    Open official source ↗
09

Continue exploring

Atlas is a starting point. Use these relationships to move into explanation, experiment and mission thinking.

Available now

Interrogate the floating-Saturn claim

Use bulk density carefully and identify what the ocean analogy leaves out.

academy
Relationship reserved

Build gaps from resonances

Change moon periods and watch repeated tugs organize ring-particle orbits.

lab
Relationship reserved

Listen through the rings

Explore how an internal oscillation can leave a measurable wave outside the planet.

lab