Source: wikibot/solid-angle
= Solid angle
{wiki=Solid_angle}
A solid angle is a measure of how large an object appears to an observer from a particular point of view, and it indicates the two-dimensional angle in three-dimensional space. Solid angles are measured in steradians (sr), where one steradian corresponds to the solid angle subtended at the center of a sphere by an area on its surface equal to the square of the sphere's radius.