ENCYCLOPEDIA BRITANNICA:

In 1963 Bell Laboratories assigned Arno Penzias and Robert Wilson the task of tracing the radio noise that was interfering with the development of communication satellites. Penzias and Wilson discovered that no matter where the antenna was pointed there was always non-zero noise strength, even where the sky was visibly empty.

A simple solution would have been to reset their receivers to zero, but they persisted in tracing the source.

This major discovery made by Penzias and Wilson was the cosmic background radiation and the strongest evidence for the big bang.

Penzias and Wilson won the Nobel Prize in physics for their discovery in 1978. .