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
Aonia Terra Aonia Terra Aonia Terra is a region in the southern hemisphere of the planet Mars. It is named after a classical albedo feature, the "Bay of the Muses" and its name was approved in 1979, by the International Astronomical Union (IAU) Working Group for Planetary System Nomenclature. It is centered at and covers 3900 km at its broadest extent. It covers latitudes 30 to 81 South and longitudes 60 to 163 W. Aonia Terra is an upland area notable for massive cratering including the large Lowell Crater, parts of the region features small craters, in the plain areas, Thaumasia Fossae