Question

Heat and mass transfer question:

Why blackbody does not exist? What if there is a "blackbody" in outer space without any contact to any object, so no conduction no convection, can I emit its 100% energy? Why not?

Answer 1

A blackbody refers to an opaque object that emits thermal radiation. A perfect blackbody is one that absorbs all incoming light and does not reflect any. At room temperature, such an object would appear to be perfectly black (hence the term blackbody). However, if heated to a high temperature, a blackbody will begin to glow with thermal radiation.

When a black body is at a uniform temperature, its emission has a characteristic frequency distribution that depends on the temperature. Its emission is called black-body radiation. The concept of the black body is an idealization, as perfect black bodies do not exist in nature.

A “Black Body” is an conceptual object that absorbs ALL electromagnetic radiation. It is conceptual because, like a perfect circle, there is no such observed object in the universe, and its unclear in theory if its possible for such an object to exist.