At first listen, you might think you were hearing something like this:
click to play audio
That’s a sound it’s good to hear in the woods these days. The mid-Atlantic winter has been hard on us, and the singing of frogs brings hope that today’s Spring Equinox has really arrived.
Those are ‘spring peepers,’ tiny chorus frogs that awaken and sing in vernal puddles each year in forest wetlands. They’re tiny: adults rarely more than an inch and a half in length. I am transported by the sound: these durable creatures rise from the frozen mud and sing for love in one of the first bright declarations of spring.
But even more miraculous that these singing amphibians is the first recording. Play it again. What you’re listening to is the dawn chorus of the planet Earth, sounds emitted by the energetic particles of the earth’s magnetosphere, stimulated by the solar wind.
These radio waves are at frequencies which are audible to the human ear, if sound traveled in a vacuum, and if you could expose your ear in space! Here they were recorded by two satellites studying the Van Allen belts and other phenomena of the near solar system.