The Earthsound Project was a planetary listening experiment whose aim was to bring the low-frequency natural sounds of Earth into worldwide conscious awareness.

The project began with a single seismometer: a sensitive instrument that detects the Earth's microscopic and inaudible seismic vibrations. Its recorded signals were digitally transposed into audible sound, to be broadcast to nearby listeners via low-power FM radio and streamed around the world via the Internet.

Since those humble beginnings, many more sensors were brought online — seismic, atmospheric, oceanic. The Planetary Sound Machine — the custom software that powered the project — gathered signals from about two-dozen sensors scattered around the world — from Scotland to Antarctica, from Uganda to Alaska — and streamed their sounds in near-real-time via the project’s website for all to hear.

These sounds of the Earth are not to everyone's taste. Still, there is great beauty here, and I hope that some hardy listeners will find —as I do — some nourishment in exploring our planet's remarkable subaudible acoustic terrain.