Cosmic Background Explorer (COBE)

A NASA astronomy satellite launched in 1989 to scan the sky and map diffuse far-infrared and millimetre-wave radiation. It measured a temperature of 2.73 K for the cosmic background radiation and confirmed that it is entirely thermal radiation in origin, in accordance with the hot Big Bang theory. Infrared detectors mapped the distribution of dust in the Milky Way and uniform diffuse radiation over the whole sky.