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
Famous quotes containing the word sphere:
“Everything goes, everything comes back; eternally rolls the wheel of being. Everything dies, everything blossoms again; eternally runs the year of being. Everything breaks, everything is joined anew; eternally the same house of being is built. Everything parts, everything greets every other thing again; eternally the ring of being remains faithful to itself. In every Now, being begins; round every Here rolls the sphere There. The center is everywhere. Bent is the path of eternity.”
—Friedrich Nietzsche (1844–1900)
“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)
“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)