Spherical lune

For the plane geometry region, see Lune (geometry).
This article is about the surface. For the volume, see Spherical wedge.
The two great circles are shown as thin black lines, whereas the spherical lune (shown in green) is outlined in thick black lines. This geometry also defines lunes of greater angles: {2}π-θ, and {2}2π-θ.

In spherical geometry, a spherical lune (or biangle) is an area on a sphere bounded by two half great circles which meet at antipodal points.[1] It is an example of a digon, {2}θ, with dihedral angle θ.[2] The word "lune" derives from luna, the Latin word for Moon.

  1. ^ Davis, Elwyn H. (1999). "Area of spherical triangles". The Mathematics Teacher. 92 (2): 150–153. doi:10.5951/MT.92.2.0150. JSTOR 27970882.
  2. ^ Weisstein, Eric W. "Spherical Lune". MathWorld.