Europa spacepedia

Planet of Origin



Galileo Galilei

Date of Discovery

January 8, 1610

Surface Color

Brown (reddish on different geological features)


Porous water ocean

Alternate Name(s):

Jupiter II

Europa, also known as Jupiter II, is the smallest of the Galilean moons, behind Io, Callisto, and Ganymede, and is one of the satellites belonging to Jupiter. This moon was found by Galileo Galilei and the less credited, Simon Marius, on January 8, 1610, the day after Ganymede, the largest of Jupiter's natural satellites, was discovered.


Like many other of Jupiter's moons, no one knows how Europa was formed. Astronomers believe that Europa was a stray meteor in space, and was pulled in by Jupiter's strong gravitational pull.


Europa contains an ocean deep inside of the moon, just like Ganymede. Tidal flexing, which is flexing caused by gravitational pulls between surrounding moons, keeps the ocean liquefied.


The surface of Europa is made of silicate rock. Europa has one of the smoothest coats of ice in the Solar System on its surface. The surface is full of streaks yet craters do not appear frequently on Earth's Moon.