Transcript: The concept of thermal radiation is fundamental to our understanding of energy and temperature. The basic principles were enunciated a hundred years ago by the German physicist Wilhelm Wien. First, all objects in the universe emit a thermal spectrum spanning a broad range of wavelengths. Second, the amount of radiation and the wavelength of the maximum energy of emission depend on the temperature of an object but not on its chemical composition, and third, the higher the temperature, the larger the amount of thermal emission, and the shorter the wavelength of the peak of the emission.