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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Famous quotes containing the word sphere:
“Thought dissolves the material universe by carrying the mind up into a sphere where all is plastic.”
—Ralph Waldo Emerson (1803–1882)
“If today there is a proper American “sphere of influence” it is this fragile sphere called earth upon which all men live and share a common fate—a sphere where our influence must be for peace and justice.”
—Hubert H. Humphrey (1911–1978)
“O sun,
Burn the great sphere thou mov’st in! darkling stand
The varying shore o’ th’ world!”
—William Shakespeare (1564–1616)