Sphere two poles is called the axis of rotation. Circles on the sphere that are parallel to the equator are lines of latitude. This terminology is also used for such approximately spheroidal astronomical bodies as the planet Earth (see geoid). Any plane that includes the center of a sphere divides it into two equal hemispheres. Any two intersecting planes that include the center of a sphere subdivide the sphere into four lunes or biangles, the vertices of which all coincide with the antipodal points lying on the line of intersection of the planes. The antipodal quotient of the sphere is the
Sphere spectrum denoted by formula_1. Sphere spectrum In stable homotopy theory, a branch of mathematics, the sphere spectrum "S" is the initial object in the category of spectra. It is the suspension spectrum of "S", i.e., a set of two points. Explicitly, the "n"th space in the sphere spectrum is the "n"-dimensional sphere "S", and the structure maps from the suspension of "S" to "S" are the canonical homeomorphisms. The "k"-th homotopy group of a sphere spectrum is the "k"-th stable homotopy group of spheres. The localization of the sphere spectrum at a prime number "p" is called the local sphere at