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
Hard Time on Planet Earth Hard Time on Planet Earth Hard Time on Planet Earth is an American science fiction series that aired on CBS as a midseason replacement in 1989. Airing for 13 episodes, the series starred Martin Kove and was created by Jim and John Thomas. Scheduled opposite NBC's "Unsolved Mysteries" and ABC's "Growing Pains" on Wednesdays, "Hard Time on Planet Earth" ranked 65th out of 81 programs upon its premiere. Ratings for the series never improved and the series was canceled by CBS in May 1989. The last episode aired on June 21, 1989. The main character was an alien Elite Military