In 1965, at the Horn Antenna in New Jersey, scientists Robert Wilson and
Arno Penzias were getting ready to map the radiation in our galaxy.
The Horn Antenna, New Jersey
But what they were about to discover was much bigger and would earn them a Nobel prize in the process.
The Horn Antenna was designed to funnel in radiation in the form of radio waves, but before they could start they had to check that it was working accurately.
Dr Arno Penzias - "Here we had purposely picked a portion of the spectrum, a wavelength of 7cm, where we expected nothing or almost, almost nothing, no radiation at all from the sky."
Dr Robert Wilson - "Instead, what happened is that we found radiation coming into our antenna from all directions. It's just flooding in at us."
It was an embarrassing start for the scientists. Their experiment was going wrong before it had even begun.
They had to uncover the cause of this unexpected radiation before they could proceed.
Dr Arno Penzias - "Naturally we focused first on the antenna. That was an attractive place for pigeons. We didn't mind that because they flew away when we, when we came, except that they had coated the surface with a white... white sticky material. When we were able to dismantle our antenna and clean these surfaces, we found to our surprise that most of the effect was still there. So now we were stuck with the sky beyond, which was not easy for us to accept, that this radiation was coming from somewhere in really deep cosmic space, beyond any radio sources that any of us knew about or even dreamed existed."
But at Princeton University, only 30 miles from the antenna, Prof Bob Dicke and his team were looking for the exact radiation that Wilson and Penzias had found.
They believed that if the Big Bang theory was correct - that the Universe had started from a single point in time and space - then there would be radiation left behind.
Prof Jim Peebles, Princeton University - "Well, Bob received the call, we heard the discussion in the background, bits and pieces of it, couldn't imagine what was happening, Bob came back and said, well boys, I think we might have it."
The radio waves that Wilson and Penzias had discovered confirmed Bob Dicke's predictions.
They had found cosmic microwave background radiation.
Cosmic Microwave Background Radiation
Radiation that was emitted when the Universe first formed.
Their accidental discovery led them to win a Nobel prize in physics in 1978.
And to think, they originally thought it was the pigeons!