In 1964, physicists Arno Penzias and Robert Wilson were working at Bell Labs in Holmdel, New Jersey, setting up ultra-sensitive microwave receivers for radio astronomy observations.
No matter what the two did, they couldn't rid the receivers of background radio noise that, puzzlingly, seemed to be coming from all directions at once. Penzias contacted Princeton University physicist Robert Dicke who suggested that the radio noise might be cosmic microwave background radiation (CMB), which is primordial microwave radiation that fills the universe.
And that is the story of the discovery of CMB. Simple and elegant.
For their discovery, Penzias and Wilson received the 1978 Nobel Prize in Physics, and for good reason. Their work ushered us into a new age of cosmology, allowing scientists to study and understand our universe as never before.
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Yet, this discovery also led to one of the most surprising findings in recent history: Unique features in the CMB could be the first direct evidence we've ever had of the multiverse — of an infinity of worlds and alien peoples that exist beyond the known universe.
However, to properly understand this extraordinary claim, it's necessary to first take a journey back to the beginning of space and time.
The history of the universe
According to the broadly accepted theory for the origin of our universe, for the first several hundred thousand years after the Big Bang, our universe was filled with a ferociously hot plasma comprised of nuclei, electrons, and photons, which scattered light.