Penzias & Wilson · CMB
Could antenna noise be the sound of the universe?
That time, that place
Penzias and Wilson set out to make radio observations with Bell Labs' great horn antenna, a device originally built for satellite communication.
And there was a hiss they could not get rid of.
Why this question
They did everything they could think of to find the source.
They pointed the antenna in different directions: identical. They observed across seasons: unchanged. It was not coming from the city, and not from any particular place in the sky.
They found pigeons nesting inside the horn and evicted them, then scrubbed out what the pigeons had left. The hiss remained.
What was found
At that same time, some thirty kilometers away at Princeton, Dicke's group was looking for something.
If the universe began hot, that light should still be here — stretched and cooled by expansion into very cold microwaves filling the whole sky evenly. They were building an instrument to detect it.
A telephone call connected the two groups. Dicke is said to have hung up and told his colleagues that they had been scooped.
The noise they had been trying to remove was the oldest light in the universe.
Whether the universe had a beginning could not be settled by observation
Very cold microwaves arriving identically from every direction
With this, the steady-state model of a universe without beginning or end collapsed