Europa/Moon

A moon of the planet Jupiter.

Recent observations of the magnetic field around Europa by the [Galileo spacecraft]? suggest that Europa has a crust of water ice, a mantle of liquid water, and a core of rock.

http://www.jpl.nasa.gov/galileo/europa/

It has been suggested that life may exist in this under-ice ocean.

Data for Europa:

• Discovery: January 7, 1610 by Galileo Galilei
• Diameter (km): 3,138
• Surface Area (km²): 3.1e7
• Mass (kg): 4.8e22 kg
• Mass (Earth = 1) 0.0083021
• Surface Gravity (Earth = 1): 0.135
• Mean Distance from Jupiter (km): 670,900
• Mean Distance From Jupiter (Rj): 9.5
• Mean Distance from Sun (AU): 5.203
• Orbital period (days): 3.551181
• Rotational period (days): 3.551181
• Density (gm/cm) 3.01
• Orbit Eccentricity: 0.009
• Orbit Inclination (degrees): 0.470
• Orbit Speed (km/sec): 13.74
• Escape velocity (km/sec): 2.02
• Visual Albedo: 0.64
• Surface Composition: Water Ice