Big Bang Noise The hiss from an FM radio between stations

The hiss from an FM radio between stations is a remnant sound from the Big Bang, approximately 13.8 billion years ago.

When a radio is tuned to an unused frequency, it picks up a variety of signals, including thermal noise from the radio’s components and cosmic background radiation. The CMB is the remnant radiation from the Big Bang, and it fills the universe with a nearly uniform glow at a temperature of about 2.7 Kelvin. This radiation contributes to the static that can be heard on radios, especially in the absence of stronger local radio signals.

In summary, while the static noise is not solely due to the CMB, the CMB is a significant contributor to the background noise that can be detected on radios when they are not tuned to a specific station.