Planet earth churns out a wide variety of natural radio waves. Most of them are very, very low in frequency, sometimes as low as just a few hertz. Receivers can pick up these waves and convert them into sounds. Haunting, ethereal sounds. Here is a brief sampling of the cornucopia of earth radiation.
Below is a recording of solar winds blowing across the upper atmosphere as they pass over the earth. Sometimes these winds excite sparse gasses enough to spark very high frequency waves--light--and produce what we know as the aurora borealis. But they can also produce enough vibration in the magnetosphere to be detected by the antennas down here on earth. I suggest you listen to the very low frequency recording below while watching the video above. It is, literally, nature's soundtrack to this stunning time-lapse film captured by the International Space Station as it passed over a geomagnetic storm in the south Indian Ocean.
Since wavelengths for these frequencies are extremely long, they may arrive from hundreds or thousands of miles away, or deep inside the earth. You might hear a large number of lightning strikes from all across the earth from your living room. Radio enthusiasts dub the cascading sounds of multiple strikes across the earth a “chorus,” and the shrill rising tones “whistlers.”
Other planets have these noises, too. When the Voyager 1 probe passed by Jupiter, it recorded detailed electromagnetic readings from the planet’s atmosphere, and beamed them back toward earth.
Very, ultra, and extremely low frequencies are also used for radio communications. Their low frequency makes them unsuitable for any high data rate transmission, but their long wavelengths make them ideal for long distance communications. Submarines use them for this reason, they can dial back to the mainland from underwater, from anywhere in the world. Take a listen.
Leading video taken by the International Space Station. Audio Courtesy, SP McGreevy, "Space Audio," and "Dorset Radio."
