Planet

A planet was a celestial body that was in orbit around a star, had sufficient mass for its self-gravity to overcome rigid body forces so that it assumed a nearly round shape, was neither a star nor a moon of a planet, and had cleared out the area around its orbit as it formed by causing all other smaller bodies in its orbit to accrete with it. As a consequence, it would not share its orbital region with any other bodies of significant size, except for moons or those collected later under its gravitational influence.

Depending on the tilt of the planet's axis, planets also had varied seasons with ranging temperatures and weather. Planets were extremely varied in terms of environmental conditions and landscape, ranging from completely oceanic (such as Manaan and Kamino) to thick arboreal rainforests (such as Kashyyyk and Felucia). Some planets, like Geonosis, Korriban, and Tatooine, were completely barren and desolate, covered in little more than rock and sand; while others (such as Coruscant and Taris) became ecumenopoleis, in which the entire planetary surface was covered by one gigantic city. Many planets, like Dantooine, Naboo, Alderaan, and Corellia, contained a mix of landscapes, with various continents, oceans, and mountains.

Most life-bearing planets had primarily nitrogen and oxygen-based Type I atmospheres; though some (such as Dorin, Gand, and Skako) had unique atmospheres to which their native life forms had adapted. Gas giants, planets made up of primarily gaseous layers, were rarely inhabited, though they were sometimes used for resource collection (such as the Tibanna gas operations on Bespin).