Solid angle a solid angle in steradians is the following ratio: where A is the spherical surface area and r is the radius of the considered sphere. Solid angles are often used in physics, in particular astrophysics. The solid angle of an object that is very far away is roughly proportional to the ratio of area to squared distance. Here "area" means the area of the object when projected along the viewing direction. The solid angle of a sphere measured from any point in its interior is 4 sr, and the solid angle subtended at the center of a cube by one
Solid surface smaller, regional manufacturers produce for local markets. Although solid surface faces competition from natural stone and engineered stone/quartz surfacing, the material is popular in Asia, particularly in residential new construction. An emerging market for solid surface is in commercial and industrial settings, where its non-porous characteristics, combined with durability, renewability and formability make it the material of choice for many designers and architects. Also appealing, is the wide range of colors and textures, as well as the ability to custom-color the material for large projects. Hospitals, in particular, employ large amounts of solid surface for sinks, showers, nursing stations and