|See also Galilean satellite the second largest (but faintest) of the four Galilean satellites of Jupiter, discovered in 1610 by Galileo. Approximate diameter: 4800 km; orbital radius: 1 883 000 km|
|Callisto (kə-lĭs'tō) Pronunciation Key
One of the four brightest satellites of Jupiter and the eighth in distance from the planet. Originally sighted by Galileo, it is the largest planetary satellite.