Europa

Moon· orbits Jupiter

Europa is the smoothest Galilean moon — a cracked ice shell over a global saltwater ocean thought to hold more water than all of Earth's, making it a leading target in the search for life.

Open in 3D viewSee Europa in the live, interactive 3D map

Key facts

Mass

4.80 × 10²² kg

0.00804 M⊕

Radius

1,561 km

90% of our Moon's radius

Surface gravity

1.32 m/s²

13% of Earth's gravity

Day length

3.5 days

Orbit around Jupiter

3.53 Earth days

Science

Physical

Mass: 4.80 × 10²² kg · 0.00804 M⊕; JPL / IAU mean radii; spacecraft-tracked GM where measured
Radius: 1,561 km · 90% of our Moon's radius; JPL / IAU mean radii; spacecraft-tracked GM where measured
Density: 3,014 kg/m³ · 3× water; Computed from mass and radius
Surface gravity: 1.32 m/s² · 13% of Earth's gravity; Computed from mass and radius
Escape velocity: 2.03 km/s · 18% of Earth's escape velocity; Computed from mass and radius

Orbit around Jupiter

Distance from Jupiter: 671,100 km; From JPL orbital elements
Orbital period: 3.5 days; From JPL orbital elements
Eccentricity: 0.009; From JPL orbital elements
Inclination to Jupiter's Laplace plane: 0.50 °; From JPL orbital elements · The Laplace plane is the one a moon's orbit precesses about: close in it is the planet's equatorial plane, the plane of the rings, and further out it tilts toward the planet's own orbit.

Rotation

Rotation period: 3.5 days
Tidal locking: Tidally locked to its parent

Temperature

Minimum: 50 K (-223 °C)
Mean: 102 K (-171 °C)
Maximum: 125 K (-148 °C)

Composition

Bulk composition: A water-ice crust over a probable global saltwater ocean, surrounding a silicate mantle and an iron core.

Radiation & temperature

Insolation: 0.0355 S⊕ · 4% of the sunlight Earth receives; Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
Bond albedo: 0.62 · reflects 62% of incoming sunlight
Equilibrium temperature: 95 K (-178 °C); Computed from albedo + distance from the Sun (airless black body)
Measured mean temperature: 102 K (-171 °C)
Greenhouse warming: +7 K; Measured temperature minus the airless equilibrium — the greenhouse effect