Europa is one of the four Galilean moons of Jupiter with Io, Ganymede and Callisto being the other three. Despite its quite beautiful appearance, which to me, looks like a weathered pearl, it is also considered the holy grail of exobiology to many scientists, who have been searching for traces of extraterrestrial lifeforms beyond the little blue marble we have called 'home' over the course of the existence of our species.
This particular image of a gibbous Europa was captured by the Galileo spacecraft, which studied the behemoth planet Jupiter and its large collection of interesting satellites. Visible here, are plains of ice, lit up by a distant beam of star light, cracks that span the width of the entire moon, dancing across the horizon and dark patches in between, that are likely composed of bits of frozen water and dirt.
While Europa is almost the same size as Luna, it is much, much smoother and arguably more interesting, as astrobiologist think there is a good possibility that microbial life exists deep beneath the frozen surface of this miniature world, that likely holds an active ocean that holds many tantalizing secrets we will hopefully find someday.
You can see a larger version if this image here:
"Europa: Facts About Jupiter's Icy Moon and Its Ocean:"
Image Credit - Galileo Project, JPL, NASA; reprocessed by Ted Stryk
This article is part of a series on the moons of Jupiter.