Lightning is the main source of Earth songs.
Taking world music to new heights, space physicists have been capturing Earth songs - natural radio waves that can be heard with an online receiver. The source of most VLF emissions on Earth is lightning strikes which emit a broadband pulse of radio waves, just as they unleash a visible flash of light. Some of these make crackling sounds when heard through the loudspeaker of a radio. They sound like twigs snapping or bacon frying. Sferics are caused by lightning strokes within a thousand kilometers or so of the receiver.