Planets & Moons
The Galilean Moons
In 1610 famed Italian astronomer Galileo Galilei discovered four of Jupiter’s moons; Europa, Ganymede, Callisto, and Io. These four are now referred to as the Galilean moons and they are the four largest moons of Jupiter. Io Io is the innermost moon and the second smallest of the Galilean moons. Read more…