Launched on November 18, 1989, Cosmic Background Explorer (COBE) was a satellite sent into orbit to observe the cosmic background. Created through the effort of over one thousand people, the satellite carried three separate instruments for observation: DMR (Differential Microwave Radiometer), DIRBE (Diffuse Infrared Background Experiment), and FIRAS (Far Infrared Absolute Spectrophotometer). COBE is most famous for the data produced by FIRAS and DMR regarding the cosmic microwave background.

The primary goal of FIRAS was to compare the spectrum of the cosmic microwave background to that of an ideal blackbody. The instrument collected data by comparing the intensity of the cosmic microwave background to the intensity of a calibrated blackbody for a given wavelength of radiation. FIRAS covered the range of the spectrum from 0.1 mm to 10 mm in wavelength. After ten months of operation, results showed that the spectrum of the cosmic microwave background...