Moon of Jupiter
Europa
An ice-shelled ocean world in step with Io and Ganymede.
Europa circles Jupiter every 3.55 days, exactly twice as long as Io and half as long as Ganymede. That resonance keeps its orbit slightly stretched, so Jupiter's tides knead its interior. Beneath its icy shell lies a saltwater ocean that may hold twice as much water as Earth's oceans.
How it moves
- Europa orbits Jupiter every 3.551 days at about 671,100 km.
- Its period is twice Io's and half Ganymede's, part of the 1:2:4 Laplace resonance.
- Europa is tidally locked, keeping one face toward Jupiter.
- Its slightly eccentric orbit (0.009) means tidal flexing changes as it moves around Jupiter.
Facts
- Mean radius
- 1,560.8 km
- Mass
- 4.800e+22 kg
- Surface gravity
- 1.31 m/s²
- Rotation period
- 85.228 hours
- Orbital period
- 3.551 days
- Average orbital distance
- 671,100 km
- Eccentricity
- 0.009
- Discovered
- January 8, 1610, by Galileo Galilei
Europa's hidden ocean may hold about twice as much water as all of Earth's oceans.
Sources: nssdc.gsfc.nasa.gov, ssd.jpl.nasa.gov, ssd.jpl.nasa.gov