A **sphere** (from Greek σφαῖρα — *sphaira*, "globe, ball") is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle, which is in two dimensions, a sphere is the set of points which are all the same distance *r* from a given point in space. This distance *r* is known as the "radius" of the sphere, and the given point is known as the center of the sphere. The maximum straight distance through the sphere is known as the "diameter". It passes through the center and is thus twice the radius.

In mathematics, a careful distinction is made between the sphere (a two-dimensional surface embedded in three-dimensional Euclidean space) and the ball (the interior of the three-dimensional sphere).

Read more about Sphere: Volume of A Sphere, Surface Area of A Sphere, Equations in R3, Terminology, Hemisphere, Generalization To Other Dimensions, Generalization To Metric Spaces, Topology, Spherical Geometry, Eleven Properties of The Sphere, Cubes in Relation To Spheres

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**sphere**there are multiple cuboids that may be inscribed within the

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**sphere**surfaces so determined ... In the usual case of two intersections of three

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**sphere**in a moderately dense

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**Sphere**Characterization

... In mathematics, a Kline

**sphere**characterization, named after John Robert Kline, is a topological characterization of a two-dimensional

**sphere**in terms of what ... A simple closed curve in a two-dimensional

**sphere**(for instance, its equator) separates the

**sphere**into two pieces upon removal ... If one removes a pair of points from a

**sphere**, however, the remainder is connected ...

**Sphere**Electron Transfer

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### Famous quotes containing the word sphere:

“In science, as in art, and, as I believe, in every other *sphere* of human activity, there may be wisdom in a multitude of counsellors, but it is only in one or two of them.”

—Thomas Henry Huxley (1825–95)

“It is in the nature of allegory, as opposed to symbolism, to beg the question of absolute reality. The allegorist avails himself of a formal correspondence between “ideas” and “things,” both of which he assumes as given; he need not inquire whether either *sphere* is “real” or whether, in the final analysis, reality consists in their interaction.”

—Charles, Jr. Feidelson, U.S. educator, critic. Symbolism and American Literature, ch. 1, University of Chicago Press (1953)

“One concept corrupts and confuses the others. I am not speaking of the Evil whose limited *sphere* is ethics; I am speaking of the infinite.”

—Jorge Luis Borges (1899–1986)