All normal (baryonic) matter emits electromagnetic radiation when it has a temperature above absolute zero.

When can you expect a body to emit blackbody radiation?

All normal (baryonic) matter emits electromagnetic radiation when it has a temperature above absolute zero.

What causes black body radiation?

The radiation of a blackbody radiator is produced by the thermal activity of the material, not the nature of the material, nor how it got thermally excited. Some examples of blackbodies include incandescent light bulbs, stars, and hot stove tops. The emission appears as a continuous spectrum (Figure 1.1.