Galactic plane

The galactic plane is the plane in which the majority of a flattened galaxy's mass lies. The most commonly discussed example is the plane on which the Earth's galaxy, the Milky Way, lies, which is also called the Milky Way's plane or plane of the Milky Way. One direction perpendicular to the plane is called below or south, while the opposite direction is called above or north. From Earth, due galactic south is marked by the south galactic pole, which lies in Sculptor, and due galactic north is marked by the north galactic pole, which lies in Coma Berenices, near the bright star Arcturus. These are defined to lie roughly in the same directions as the Earth's north and south poles.