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AsteriaStar

Moon

Ganymede

Type
Moon
Diameter
5,262 km

Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing by Thomas Thomopoulos © CC BY · NASA media (public domain)

Overview

Scientific overview

Ganymede is a moon orbiting Jupiter.

Physical characteristics

Mass
0.148 ×10²⁴ kg
Diameter
5,262 km
Radius
2,631.2 km
Density
1.942 g/cm³
Surface gravity
1.43 m/s² · derived
Escape velocity
2.7 km/s · derived
Albedo
0.43
Magnitude
4.61

Derived values

Computed from source-backed inputs via standard formulae — not observations. Every input and constant is traced below.

  • Escape velocity2.7 km/sderived
    Formula & inputs

    Formula: v = √(2GM / r) (v1.0.0, impl v1.0.0)

    Inputs:

    • mass1e24Kg = 0.14815 ×10²⁴ kg · NASA
    • radiusKm = 2631.2 km · NASA

    Assumptions: G = 6.674e-11 m³ kg⁻¹ s⁻² (CODATA 2018)

    Limitations: Assumes a spherical, non-rotating body.; Inputs carry no catalogued uncertainty, so none is propagated.

    Uncertainty: not propagated (inputs carry no catalogued uncertainty)

    Computed as of 2026-06-29.

  • Surface gravity1.43 m/s²derived
    Formula & inputs

    Formula: g = GM / r² (v1.0.0, impl v1.0.0)

    Inputs:

    • mass1e24Kg = 0.14815 ×10²⁴ kg · NASA
    • radiusKm = 2631.2 km · NASA

    Assumptions: G = 6.674e-11 m³ kg⁻¹ s⁻² (CODATA 2018)

    Limitations: Assumes a spherical, non-rotating body.; Inputs carry no catalogued uncertainty, so none is propagated.

    Uncertainty: not propagated (inputs carry no catalogued uncertainty)

    Computed as of 2026-06-29.

Scale

Compared to Earth

Earth
Ganymede

Ganymede is 2.4× smaller than Earth

5,262 km across · Earth is 12,742 km

Gallery

Close-up of Dark Side of Jupiter Moon Ganymede

This image of the dark side of the Jovian moon Ganymede was obtained by the Stellar Reference Unit star camera aboard NASA's Juno spacecraft during its June 7, 2021, flyby of the icy moon.

2021

NASA/JPL-Caltech/SwRI · NASA media (public domain)

Source archive ↗

Observation

How this was captured

Source
NASA
Observation date
2022-02-22

Sources

The primary and reference sources this topic draws on.

  • NASANational Aeronautics and Space Administration

    Mission data, planetary science, space telescopes, and public-domain imagery.

    Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.

  • NASA JPLJet Propulsion Laboratory / Solar System Dynamics

    Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.