Europa and Callisto under the watchful gaze of Jupiter
March 19, 2003
One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet. The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa.
Topics: Callisto, Planetary science, Moons of Jupiter, Environment, Cassini–Huygens, Titan, Exploration of Jupiter, Europa, natural satellite, Saturn, Solar System, Planet, Jupiter