Albedot

Albedot is a theoretical metric proposed in some educational and speculative discussions to quantify surface reflectivity under standardized illumination. The term blends albedo with the suffix -dot to indicate a dimensionless index. In its common formulation, albedot is defined as the ratio of reflected radiance from a surface, integrated over the standard solar spectrum and the visible range, to the incident irradiance, with normalization for a specified surface-illumination geometry such as a normalized Lambertian hemisphere. Under the standard geometry, albedot approximates the conventional albedo, but the metric is intended to emphasize comparisons across surfaces in a geometry-aware way. The scale is unitless and typically treated as 0 to 1, where 0 denotes a perfect absorber and 1 a perfect reflector, assuming the same spectral weighting and geometry.

Usage is mostly educational or speculative, used to illustrate how roughness, texture, or coating affect reflectivity in a way that mirrors albedo but with explicit geometric context. It is not an officially recognized physical quantity in mainstream climatology or planetary science, where standard albedo, BRDF, and radiative transfer models are used. As a concept, albedot can facilitate discussions about planetary climate, material design, and fictional worldbuilding.

See also: albedo, bidirectional reflectance distribution function, Lambertian reflectance.