Tonight, I present Part II on the Cosmic Microwave Background, focusing on its discovery. These entries on the CMB are part of a larger series on the Big Bang and inflationary cosmology. The prediction of the CMB (by Alpher and Herman, with Gamow) as a vestige of the Big Bang was discussed in the previous entry.
The discovery of the CMB derives from radio astronomy. In the early 1960s, the Bell Lab scientists Arno Penzias and Robert Wilson were working on some radio observations. There was a persistent noise in their observations and despite assiduous attempts by Penzias and Wilson to account for and remove the noise, it wouldn't go away. According to Simon Singh's book, Big Bang:
What the two frustrated radio astronomers had not realised was that they had stumbled into one of the most important discoveries in the history of cosmology. They were completely oblivious to the fact that the omnipresent noise was actually a remnant of the Big Bang: it was the 'echo' from the early expansion phase of the universe. This annoying 'noise' would turn out to be the most convincing evidence yet that the Big Bang model was correct (p. 429).
Penzias and Wilson were eventually put in touch with a team from nearby Princeton, Robert Dicke and James Peebles, who, it appears, were busy "re-inventing the wheel" regarding the CMB. According to Singh:
Dicke and Peebles had no idea that they were walking in the fifteen-year-old footstepts of Gamow, Alpher, and Herman. Independently and belatedly, they were re-postulating the CMB radiation (p. 431).
Among all the players in the CMB saga, the only ones to receive the Nobel Prize for it were Penzias and Wilson, in 1978 (official press release). The award to Penzias and Wilson, with no such recognition ever to CMB theorists Alpher, Herman, and Gamow, is discussed on this list of Nobel Prize controversies. Singh details the plight of Alpher, Herman, and Gamow:
When Gamow, Alpher, and Herman heard of the discovery of the CMB radiation, their joy was mixed with some bitterness. It was they who had predicted this echo of the Big Bang well before Dicke and Peebles, but they received virtually no acknowledgement for their pioneering efforts. They were not mentioned in the initial pair of papers [by Penzias and Wilson; and by Dicke and colleagues] announcing the breakthrough in the Astrophysical Journal... (p. 434).
When a journalist later asked Alpher if he had felt offended by Penzias and Wilson's failure to acknowledge his contribution, he spoke his mind: 'Was I hurt? Yes! How the hell did they think I'd feel? I was miffed at the time that they'd never even invited us down to see the damned radio telescope. It was silly to be annoyed, but I was' (p. 436).
Singh's book does, however, detail the efforts by Penzias to make contact with and publicly acknowledge the contributions of Gamow, Alpher, and Herman.