What do radio astronomers listen for?
Actually, radio astronomers very seldom “listen” with their ears to the signals they are receiving. If you do listen to some of the radio telescope output that has been translated to an audio signal you can hear, it sounds just like the static you hear when your television is tuned to a channel where no station is present. It is this broad noise signal that is of interest to radio astronomers who measure it in many ways, but only listen in perhaps to hear what kind of man-made interference is messing up their measurements.