Cosmic microwave background, as seen by Penzias and Wilson in 1963 and 1964. When using a radio antenna at Bell Laboratories, USA, Penzias and Wilson failed to eliminate a persistent background noise. It was later realised that the noise was the cosmic background radiation, predicted in 1948 by Gamow and Herman, and evidence for the 'big bang' theory of the origin of the universe. The discovery won Penzias and Wilson the Nobel Prize in Physics in 1978. This image is based on and designed to be compared to the much more detailed results obtained by the WMAP (Wilkinson Microwave Anisotropy Probe) spacecraft in 2003. See image C005/0931.