The Umov effect, also known as Umov's law, is a relationship between the albedo of an astronomical object, and the degree of polarization of light reflecting off it.
[1] The effect was discovered by the Russian physicist Nikolay Umov in 1905,[2] and can be observed for celestial objects such as the surface of the Moon and the asteroids.
The degree of linear polarization of light P is defined by where
Umov's law states where α is the albedo of the object.
The law is only valid for large phase angles (angles between the incident light and the reflected light).