Gravity plane

A gravity plane was a geometrical plane generated by certain large, non-spherical objects towards which other objects "fell". Gravity was what held an atmosphere around plants and spelljammers and what allowed an inhabitant to walk on the surface of a world or a spacefarer to stand on the deck of a ship.

Most residents of wildpace recognized that every physical object had its own gravity and assumed that the direction of the force was always towards what was most convenient toward sentient life. For planets, this was always toward the center of mass, but for spelljammers and other space objects, such as asteroid cities, the force was usually perpendicular to a horizontal plane. More knowledgeable scholars of wildspace recognized that gravity planes were not natural occurrences, as was the gravity of planets, but rather the result of the special magic of spelljamming helms.

Gravity planes had two sides; that is, they attracted objects from both the bottom and the top. It was thus possible for someone to walk on the bottom of a spelljamming vessel "upside-down".

A gravity plane extended horizontally out from the massive body producing it, such that objects fell toward the empty space surrounding the body. An object falling into an empty region of the gravity plane would bob up and down, much like something floating on the ocean.