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
Science On a Sphere This work enabled MacDonald's invention to move out from the laboratory and into performance spaces. A patent was awarded to NOAA for Science On a Sphere in August 2005, with MacDonald credited as the inventor. General system architecture and configuration specifications are as follows. The carbon fiber sphere is in diameter. Other sphere sizes are possible, such as 48" and 60". Larger sizes are possible too. The 68" sphere with a single seam at the equator weighs under . The sphere is attached to the ceiling or suspension structure with a three-point suspension system to hold the sphere in place