A hypothetical system of orbiting solar power satellites meant to completely encompass a star and capture its entire energy output. / (science fiction) A solid shell of matter enclosing a star.

An instrument consisting of graduated metal circles used to represent the motions of celestial bodies around the earth.

(mathematics) A sphere with a radius of 1 unit.

(mathematics) The arranging of non-overlapping spheres in space

plural of sphere of knowledge

(topology, complex analysis) The complex numbers extended with the number ∞; the complex plane (representation of the complex numbers as a Euclidean plane) extended with a single idealised point at infinity and consequently homeomorphic to a sphere in 3-dimensional Euclidean space.

(physics) A volume whose radius is the Debye length, in which there is a sphere of influence, and outside of which charges are electrically screened.

plural of Debye sphere

plural of armillary sphere

(mythology) A continuous, glorious, harmonious set of sounds that are not audible to ordinary human beings, produced by the movement of the celestial bodies. / (figuratively) Sublime, mysterious music.