Transcript: Everything with a temperature, which is to say every object in the physical universe, emits a thermal spectrum, a broad spectrum of radiations that result directly from the random microscopic motions of atoms or molecules. This thermal radiation is also sometimes called a blackbody spectrum because of the way that physicists produce such a spectrum in the laboratory by creating a hollow cavity, lining the cavity with black so that radiation emitted through a small entrance aperture produces a thermal spectrum as it flows back out through the small aperture.