COBE: The COBE (Cosmic Background Explorer) satellite was developed by NASA’s Goddard Space Flight Center to measure the diffuse infrared and microwave radiation from the early Universe after the Big Bang. Launched in 1989 it carried three instruments, a Far Infrared Absolute Spectrophotometer (FIRAS) to compare the spectrum of the cosmic microwave background radiation with an ideal absorber and emitter of radiation ("blackbody"), a Differential Microwave Radiometer (DMR) to sensitively map the cosmic radiation, and a Diffuse Infrared Background Experiment (DIRBE) to search for the cosmic infrared background radiation. Each COBE instrument yielded a major cosmological discovery:

FIRAS - The cosmic microwave background (CMB) spectrum is that of a nearly perfect blackbody with a temperature of 2.725° ± 0.002° K. This means that the temperature of outer space is less than 3 degrees above absolute zero in every direction we can see, almost without variation. This observation matches the predictions of the hot Big Bang theory extraordinarily well, and indicates that nearly all of the radiant energy of the Universe was released within the first year after the Big Bang.

DMR - The CMB was found to have intrinsic "anisotropy" (differences dependent upon the direction or place of measurement) for the first time, at a level of a part in 100,000. These tiny variations in the intensity of the CMB over the sky show how matter and energy was distributed when the Universe was still very young. Later, through a process still poorly understood, the early structures seen by DMR developed into galaxies, galaxy clusters, and the large-scale structure that we see in the Universe today.

DIRBE - Infrared absolute sky brightness maps were obtained to carry out a search for the cosmic infrared background (CIB). The CIB represents a "core sample" of the Universe: the cumulative emissions of stars and galaxies dating back to the epoch when these objects first began to form. The COBE CIB measurements constrain models of the cosmological history of star formation and the buildup over time of dust and elements heavier than hydrogen, including those of which living organisms are composed. Dust has played an important role in star formation throughout much of cosmic history.