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
The Planets: A Modern Allegory The Planets: A Modern Allegory The Planets: A Modern Allegory is a radio play, written in verse, by Alfred Kreymborg. The first performance was on 6 June 1938 by the National Broadcasting Company at the Hayden Planetarium in New York City, and was directed by Thomas L. Riley. The play was originally set to the music of "The Planets" Suite by Gustav Holst; for the first performance the NBC Symphony Orchestra was conducted by H. Leopold Spitalny. The first broadcast was so enthusiastically received that it was repeated a few weeks later. The play describes the early history of the