Moon of Jupiter
Diameter: 3122 km
Distance: 670900 km (mean)
Period: 3.5512 days
Eccentricity: 0.009
Inclination: 0.47°
Magnitude: 5.3

Discovered in 1610 by G. Galilei, Europa is the smallest of the 'Galilean Satellites', slightly smaller than the Earth moon. It is made of silicate rock enveloped by a smooth surface of water ice with possibility of a tidally warmed, liquid ocean underneath, and therefore a top candidate for life.