DISCOVERY
In 1965 Arno A. Penzias and Robert W. Wilson discovered a low level of microwave background "noise" by testing a sensitive horn antenna designed to detect low frequency microwaves. After unsuccessful attempts to eliminate it, they pointed their antenna to another part of the sky to check whether the "noise" was coming from space, and got the same kind of signal. After many failed attempts at eliminating the "noise" they concluded that it was coming from space, but that it was uniform and coming from all directions. They later discovered that a group at Princeton had predicted that residual microwaves would be present in the universe after the Big Bang. The the background noise and he residual microwave theory were merged to explain the background radiation.