In 1964, while preparing the antenna to measure the properties of the Milky Way galaxy, Dr. Penzias and Dr. Wilson, two young radio astronomer who was new to Bell Labs, encountered a persistent, unexplained radio waves signal that seemed to come from everywhere in the sky, detected no matter which way the antenna was pointed.
The echo of the big bang had been discovered.
See an Interview with Dr. Arno Penzias by freelance journalist Marika Griehsel at the 54th meeting of Nobel Laureates in Lindau, Germany, June 2004.