This blackbody also emits thermal radiation. Like a glowing poker just out of the fire. In 1900 Max Planck characterized the light coming from a blackbody. The equation that predicts the radiation of a blackbody at different temperatures is known as Planck's Law. The hotter the blackbody the more energy emitted per unit area at all wavelengths.
Cold objects look red.
The radiated energy increases very rapidly with increasing temperature. Flux The Energy flux, F, is the power per unit area radiated from an object. The units are energy, area and time. Luminosity Total power radiated from an object.