A sea of information for creative professionals & hobbyists.

A terrestrial, telluric, or rocky planet is a planet that is primarily composed of silicate rocks and/or metals. Within our solar sytem, the terrestrial planets make up the inner planets closest to the Sun. The terms derive from Latin words for Earth (Terra and Tellus), so in certain ways, these planets are Earth-like.

Terrestrial planets are significantly different from gaseous giants, which may not even have solid surfaces and are mostly composed of a combination of hydrogen, helium, and water existing in various physical states.

Types of Terrestrial Planets

Silicate Planet - This is the standard type of telluric planet seen in our solar system, made primarily of silicon-based rocky mantle with a metallic (iron) core.

Iron Planet - A theoretical type of terrestrial planet that consists almost entirely of iron and therefore has a higher desnity and a smaller radius than other terrestrial planets of comparable mass. Mercury has a metallic core equal to 60-70% of it's planetary mass. Iron planets are believed to form in the high-tempurature regions close to a star, like Mercury, and i the protoplanetary disk is rich in iron.

Coreless Planet - A theoretical type of terrestrial planet that consists of silicate rock, but has no metallic core. In othe words, the opposite of an iron planet. The solar system we live in contains no coreless planets but chondrite asteroids are believed to form father from the start there the volatile oxidizing material is more common.

Carbon Planet (Diamond Planet) - A theoretical type of planet, composed primarily of carbon-based minerals. The solar system contains no carbon planets, but does have carbonaceous asteroids.

Super-Earths - These are planets whcih represent the upper-end of the terrestrial planet mass range.