Circle of a sphere the Equator the only great circle. By contrast, all meridians of longitude, paired with their opposite meridian in the other hemisphere, form great circles. The diameter of the sphere which passes through the center of the circle is called its axis and the endpoints of this diameter are called its poles. A circle of a sphere can also be defined as the set of points at a given angular distance from a given pole. When the intersection of a sphere and a plane is not empty or a single point, it is a circle. This can be seen as follows:
Sphere (novel) team returns to the habitat, Adams succeeds in opening and entering the sphere. Meanwhile, on the surface, a Pacific cyclone forces the supporting Naval ships to evacuate, trapping and isolating the scientists on the ocean floor for five days. Adams is found and returned to the DH-8 Habitat where he awakens with a terrible headache and little-to-no memory of how he opened the sphere or what occurred while he was inside. Immediately afterwards, the team is contacted by an intelligent, seemingly friendly alien entity that calls itself "Jerry". At first, Jerry communicates with the scientists using a numeric code transmitted