Tuning in to Big Bang’s Echo
Arno Penzias and Robert Woodrow Wilson, 1/2 of the prize
The interference you see on an analogue television screen as you try to tune in to channels might seem an unlikely form of time travel, but within this static hiss lies a glimpse of the first moments of the universe. Arno Penzias and Robert Wilson’s fortuitous discovery of a form of radio noise that bathes the cosmos provided a crucial piece of evidence for how the universe was created.
Penzias and Wilson’s attempts to listen to the microwave signals transmitted from our Solar System using a large radio antenna in Holmdel, New Jersey, were constantly being hampered by the presence of an annoying background hiss. After a year spent persistently and painstakingly trying to identify and remove all possible causes for the unwanted noise – from radio signals coming from neighbouring cities to the pigeons nesting in the horn-shaped antenna – they concluded that this interference was due to microwaves present throughout the universe and at a temperature of around three degrees above absolute zero, but they had little idea what this noise actually was.
The answer was provided by Robert Dicke at Princeton University. Searching for evidence to support the theory that the universe was created from a single, highly explosive moment, known as the Big Bang, Dicke and his colleagues were investigating a prediction first made in the 1940s that such a spectacular event should leave a faint, cold afterglow that could be detected. The noise that Penzias and Wilson were trying to remove, which became known as cosmic microwave background radiation, was the missing evidence that could back up the Big Bang theory, and this led to its acceptance as the standard model of cosmology.
The cosmic microwave background radiation is thought to have been formed shortly after the explosive event of the Big Bang, as the hot and rapidly expanding universe began to cool down. Through their discovery of this radiation, Penzias and Wilson have provided scientists with the best means available for exploring the first snapshots of the new-born universe.