From inside the horn-shaped antenna located at Bell Labs in Crawford Hill, Arno Penzias and Robert Wilson solved a puzzling and persistent mystery.
After many painstaking hours of suppressing stray radio waves, cooling the apparatus down and eliminating all possible sources of noise they decided to look inside the antenna. Finally, there, it seemed, was the solution.
Well, pigeons and their poop.
The two astronomers had found the source of the mysterious humming that seemed to permeate all their measurements of the sky. A few humble pigeons nestled inside their antenna.
With a bit of work, the pigeons were evicted and the droppings were cleaned out. At last, the astronomers could get back to work experimenting with their supersensitive receiver.
Yet, still, there was a steady, yet surprisingly intense rumble. One that seemed to spread across the sky, and that persisted throughout the day, despite the newly cleaned interior.
If it wasn’t the birds, then what was it?
In the middle of the 1900s, there were two competing theories about the origin of the universe. One put the universe as an unchanging, eternal object that had existed and would continue to exist indefinitely. This was the steady-state model of the universe.
In the other camp was the new, controversial theory on the block: the Big Bang theory, which said the whole universe came from a colossal explosion, billions of years ago.
This new theory had some interesting and, crucially, testable predictions. For one, such a tremendous blast should have released a lot of radiation. Of course, as the universe expanded this radiation would have been stretched in a process called redshift. So, rather than us all being blinded by the intense aftermath of creation every time we look up, there would instead be a faint, invisible, but detectable glow. This would take the form of microwave radiation.
Just 37 miles from Penzias and Wilson, the Princeton astrophysicists Robert Dicke, Jim Peebles and David Wilkinson set out to look for this glow.