Theoretically, the radio signals from our earliest broadcasts have been spreading outwards through space since the beginning of radio.
They’ve travelled over 100 light-years by now and, according to researchers from Cornell, may have reached 75 star systems containing at least 29 potentially habitable exoplanets.
But the strength of radio signals degrades by the inverse square law: double the distance, quarter the strength.
Combine that with the distortions (refraction, dispersion and scintillation) caused by our own atmosphere and communication satellites in orbit, as well as interaction with a whole lot of matter and gravity in space.
The result? When the signals finally reach a (very, very sensitive) radio receiver somewhere out there, it’s unlikely to be decipherable over the background cosmic noise of the Universe.
Truly lost in space.
This article is an answer to the question (asked by Jonathan Holmes, Bristol) 'Could someone across the cosmos pick up old radio programmes?'
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