球面

Also known as 2-sphere, orb

A sphere (from Ancient Greek , ) is a surface analogous to the circle, a curve. In solid geometry, a sphere is the set of points that are all at the same distance from a given point in three-dimensional space. That given point is the center of the sphere, and the distance is the sphere's radius. The earliest known mentions of spheres appear in the work of the ancient Greek mathematicians.

AI overview

A sphere is a perfectly round three-dimensional shape where every point on its surface sits at an equal distance from a central point, much like how a circle works in two dimensions. Spheres matter because they are a fundamental geometric form that appears throughout mathematics, nature, and everyday objects like planets and balls, making them essential to understanding spatial relationships and physical properties of the world around us.

AI-generated from the Wikipedia summary — may contain errors.

Key facts

Polyhedron<! Please add only parameters that make sense for a sphere. >.name: Sphere
Polyhedron<! Please add only parameters that make sense for a sphere. >.image: File:Sphere wireframe 10deg 6r.svg
Polyhedron<! Please add only parameters that make sense for a sphere. >.caption: A perspective projection of a sphere
Polyhedron<! Please add only parameters that make sense for a sphere. >.euler: 2
Polyhedron<! Please add only parameters that make sense for a sphere. >.symmetry: Orthogonal group|
Polyhedron<! Please add only parameters that make sense for a sphere. >.type: Smooth surfaceAlgebraic surface

via Wikipedia infobox

Wikidata facts

Subclass of: geometric primitive
Followed by: torus
Follows: circle
Image: Sphere Quadric.png
Said to be same as: Riemann sphere

Show 9 more facts

Commons category: Spheres
Euler characteristic: 2
topic's main category: Category:Spheres
has characteristic: genus
different from: three-ball
Commons gallery: Sphere
on focus list of Wikimedia project: Wikipedia:Vital articles/Level/4
maintained by WikiProject: WikiProject Mathematics
described by source: Encyclopædia Britannica 11th edition

Sources (4)

via Wikidata · CC0

Article · 中文

球面（英語：sphere）是三维空间中完全圆形的几何物体，它是圆球的表面（类似于在二维空间中，“圆 ”包围着“圆盘”那样）。就像在二维空间中的圆的定义一样，球面在数学上定义为三维空间中离给定的点距离相同的点的集合 r。这个距离 r 是球的半径，球（ball）则是由离给定点距离小于 r 的所有点构成的几何体，而这个给定点就是球心。球的半径和球心也是球面的半径和中心。两端都在球面上的最长线段通过球心，其长度是其半径的两倍；它是球面和球体的直径。尽管在数学之外，术语“球面”和“球”有时可互换使用，但在数学中是明确区分的：球面是一种嵌在三维欧几里得空间内的二维封闭曲面，而球是一种三维图形，其包括球面和球面内部的一切（闭球），不过更常见的定义是只包括球面内部的所有点，不包括球面上的点（开球）。这种区别并不总是保持不变，尤其是在旧的数学文献里，sphere（球面）被当作固体。这与在平面上混用术语“圆”（circle）和“圆盘”（disk）的情况类似。

Abstract from DBpedia / Wikipedia · CC BY-SA