## Sphere

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.

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### Some articles on sphere:

**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 sort of subset separates it ... 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

... ligands in complexes, are tightly bound and constitute the "inner

**sphere**" ... Reactions in which these participate are called inner

**sphere**redox reactions ... The free solvent molecules constitute the "outer

**sphere**" ...

... Satellite position and pseudorange determines a

**sphere**centered on the satellite with radius equal to the pseudorange ... is used to estimate receiver position based on the intersection of three

**sphere**surfaces so determined ... case of two intersections of three

**sphere**surfaces, the point nearest the surface of the

**sphere**corresponding to the fourth satellite is chosen ...

... Each vertex of this polytope corresponds to the center of a 6-

**sphere**in a moderately dense

**sphere**packing, in which each

**sphere**is tangent to 70 others the best known ...

**Sphere**s

... For every

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

**sphere**... The largest cuboid which can be inscribed within a

**sphere**is a cube ...

### More definitions of "sphere":

- (
*noun*): A particular environment or walk of life.

Example:*"His social sphere is limited"*

Synonyms: domain, area, orbit, field, arena

- (
*noun*): A solid figure bounded by a spherical surface (including the space it encloses).

- (
*noun*): A particular aspect of life or activity.

Synonyms: sector

- (
*noun*): The apparent surface of the imaginary sphere on which celestial bodies appear to be projected.

Synonyms: celestial sphere, empyrean, firmament, heavens, vault of heaven, welkin

- (
*noun*): Any spherically shaped artifact.

- (
*noun*): The geographical area in which one nation is very influential.

Synonyms: sphere of influence

### Famous quotes containing the word sphere:

“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)

“I count him a great man who inhabits a higher *sphere* of thought, into which other men rise with labor and difficulty; he has but to open his eyes to see things in a true light, and in large relations; whilst they must make painful corrections, and keep a vigilant eye on many sources of error.”

—Ralph Waldo Emerson (1803–1882)

“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)