Jupiter And Family
This composite image features classic portraits of members of one of the Solar System's most prominent families - Jupiter and its four large “Galilean” moons. Starting from the top the moons are Io , Europa , Ganymede , and Callisto . The top-to-bottom order is also the order of increasing distance from Jupiter. These are big moons indeed which attend the largest planet . The smallest of the lot, Europa, is the size of Earth's moon while Ganymede is the largest moon in the Solar System. In fact, Ganymede with a diameter of 3,100 miles, is larger than the planets Mercury and Pluto . The swirling Great Red Spot appears at the edge of Jupiter. A hurricane-like storm system that has persisted for over 300 years, two to three earths could fit inside it. Battered Callisto's image was recorded during the 1979 flyby of Voyager . The other portraits were taken by the Galileo spacecraft which began exploring the Jovian system in 1995.