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:
“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)
“Every person is responsible for all the good within the scope of his abilities, and for no more, and none can tell whose sphere is the largest.”
—Gail Hamilton (1833–1896)
“Don’t feel guilty if you don’t immediately love your stepchildren as you do your own, or as much as you think you should. Everyone needs time to adjust to the new family, adults included. There is no such thing as an “instant parent.”
Actually, no concrete object lies outside of the poetic sphere as long as the poet knows how to use the object properly.”
—Johann Wolfgang Von Goethe (1749–1832)