Arno Allan Penzias (born 1933) is an American physicist.
He won the 1978 Nobel Prize in physics, together with Robert Woodrow Wilson, for their 1964 accidental discovery of the cosmic microwave background radiation (CMB): while working on a new type of antenna at Bell Labs in Holmdel, New Jersey, they found a source of noise in the atmosphere that they could not explain. After clearing the antenna of pigeon droppings, the noise was finally identified as CMB, the single most striking proof of the Big Bang.
