Lucky Starr and the Moons of Jupiter of Eternity". Consequently, there are small inconsistencies between the various novels. In the first, Ganymede is mentioned as a settled world of the Solar System, although in later novels Ganymede has no permanent settlement, and has even served as the location of a secret Sirian base. The first man on Mars is named Wingrad in "David Starr, Space Ranger", but is named Ching in "Moons of Jupiter". The name of the state that rules the Solar System also changes from novel to novel. In "Pirates of the Asteroids", it is the Terrestrial Empire; in "Oceans of Venus", it is the
Solar System model Solar System model Solar System models, especially mechanical models, called "orreries", that illustrate the relative positions and motions of the planets and moons in the Solar System have been built for centuries. While they often showed relative sizes, these models were usually not built to scale. The enormous ratio of interplanetary distances to planetary diameters makes constructing a scale model of the Solar System a challenging task. As one example of the difficulty, the distance between the Earth and the Sun is almost 12,000 times the diameter of the Earth. If the smaller planets are to be easily visible to