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:
“Prayer is the fair and radiant daughter of all the human virtues, the arch connecting heaven and earth, the sweet companion that is alike the lion and the dove; and prayer will give you the key of heaven. As pure and as bold as innocence, as strong as all things are that are entire and single, this fair and invincible queen rests on the material world; she has taken possession of it; for, like the sun, she casts about it a sphere of light.”
—Honoré De Balzac (1799–1850)
“O sun,
Burn the great sphere thou mov’st in! darkling stand
The varying shore o’ th’ world!”
—William Shakespeare (1564–1616)
“A knowledge of the Globe and its various inhabitants, however slight ... has a kindred effect with that of seeing them as travellers, which never fails, in uncorrupted minds, to weaken local prejudices, and enlarge the sphere of benevolent feelings.”
—James Madison (1751–1836)