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. The terms are derived from Latin words for Earth (Terra and Tellus), as these planets are, in terms of composition, "Earth-like".
Terrestrial planets have a solid planetary surface, making them substantially different from the much larger gas giants, which are composed mostly of some combination of hydrogen, helium, and water existing in various physical states.
Read more about Terrestrial Planet: Structure, Solar Terrestrial Planets, Extrasolar Terrestrial Planets, Types
Famous quotes containing the word planet:
“The golden mean in ethics, as in physics, is the centre of the system and that about which all revolve, and though to a distant and plodding planet it be an uttermost extreme, yet one day, when that planet’s year is completed, it will be found to be central.”
—Henry David Thoreau (1817–1862)