Greyhawk: Return to the Classic
The Space of the World of Greyhawk, not touched on to great extent in the fantasy game but sees a lot of development in the Spelljammer serise.
- Oerth: Terrestrial planet and home to the Greyhawk campaign setting. (This planetary system is geocentric, not heliocentric.)
- Kule: Tidally-locked terrestrial body. Covered with the ruins of a humanoid civilization, but lacking any air whatsoever. A magical cataclysm is suspected to have caused the depopulation. Also known as Celene.
- Raenei: Terrestrial planet, covered with earthlike features, including animals and monsters, but no sentient life. Also known as Luna.
- Liga, the Sun: Star. Has many small lakes of elemental water to keep it from burning too hot. Larger than Oerth, but orbits it anyway.
- The Grinder: Asteroid belt.
- Edill: Gas giant, populated primarily by dragons.
- Gnibile: Dark-red gas giant, with blobs of lava and shards of ice in the interior. Contains a gate to the Negative Material Plane. Populated primarily by undead.
- Conatha: Elliptical water world with two solid cores that orbit around each other. Populated by many piscine creatures, including merfolk and sahuagin.
- Ginsel: Crescent-shaped world that resembles an apple with a giant bite taken out of it. Has an atmosphere on the inside of the crescent. Basic civilized fantasy world.
- Borka: Spherical asteroid cluster with a common atmosphere. Formerly a planet inhabited by orcs, goblins and other humanoids, it was devastated by the magic of the elves.
- Greela: Another spherical asteroid cluster with a common atmosphere, although many of the asteroids bear huge forests. Home to the elves.
- The Spectre: A flat, circular disc of rock that appears to vanish and re-appear as it is seen edgewise, then rotates to show its full face. Also called The Wink. Has an atmosphere and water, but no life.