Terrestrial planet Terrestrial planet A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars. The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth ("Terra" and "Tellus"), as these planets are, in terms of structure, "Earth-like". Terrestrial planets have a solid planetary surface, making them substantially different from the larger giant planets, which are composed mostly of some combination of hydrogen, helium, and water existing in various
Return to the Lost Planet on the development of this genre in Israel. The plot follows on precisely from "The Lost Planet". A previous expedition to Hesikos, the wandering 'lost planet' which is now within a few days flight of Earth, has crash-landed, and Dr Lachlan McKinnon (its organiser), Professor Hermanoff and American engineer Spike Stranahan are marooned. McKinnon's colleagues must build and launch a spaceship from their Scottish base to travel to Hesikos, but to construct the ship they must obtain the expert assistance of Dr Andrieff, a scientist and engineer, who risks exile from his Eastern European country by so doing. The crew,