Jupiter's Moon Callisto is the second-largest moon of Jupiter, after Ganymede. It is the third-largest moon in the Solar System after Ganymede and Saturn's largest moon Titan, and the largest object in the Solar System not to be properly differentiated. Wikipedia View on Maps: google.com/maps/space/callisto Distance to Earth: 628.3 million km Orbital period: 17 days Radius: 2,410 km Gravity: 1.236 m/s² Did you know: The entire surface of Callisto is covered with craters. seasky.org