This high frequency light comes in, hit the cold surface, warms it up a bit and emits a black body spectrum of frequencies outward, most of these being below our cutoff frequency of our shell. (wattsupwiththat.com)
The information provided by spectral lines and other deviations from the perfect black body spectrum represents an entropy deficiency. (newscientist.com)
The first results from the FIRAS experiment, using only 9 minutes of data, showed that the cosmic background radiation has exactly the black - body spectrum expected in the hot big bang theory, with a temperature of 2.735 + / - 0.060 kelvin. (newscientist.com)