Callisto (moon) Callisto (moon) </math>.</ref> Callisto (Jupiter IV) 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. Callisto was discovered in 1610 by Galileo Galilei. At in diameter, Callisto has about 99% the diameter of the planet Mercury but only about a third of its mass. It is the fourth Galilean moon of Jupiter by distance, with an orbital radius of about . It is not in an orbital resonance like the three other
The Ganymede Club The Ganymede Club The Ganymede Club is a science fiction novel by American writer Charles Sheffield, published in 1995. A mystery and a thriller, the story unravels in the same universe that Sheffield imagined in "Cold as Ice". Shortly after humanity begins colonisation of the solar system, a trade war sets off vicious civil war that kills billions. The book received favorable reviews from "Library Journal" and "Kirkus Reviews", as well as in the science-fiction press. It was ranked #14 in SF novels in the 1996 "Locus" awards. The novel has been translated into Italian and was published as "Memoria