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
Stowaway to the Mushroom Planet Tyco Bass, coming to Pacific Grove, California, and visiting the two boys (Chuck and David) from the first book. He has been a traveler around the world for many years, and when he finds out about the mushroom planet, he decides to rebuild the boys' lost spaceship and return to what he knows is his ancestral home. Earlier, the boys had written a letter to a nearby university professor inviting him to come and give a lecture to their young astronomers' society. The letter arrives while the professor is away and is received by his ambitious young assistant, who comes