Infrasound is sound waves below the range of human hearing. Explosions of nuclear weapons, volcanic paroxysms and thunderstorms are heard only up close. Infrasound emitted by these phenomena can circumnavigate the globe. Therefore, even if a scientist is at a distance of half the globe, an infrasound detector will be able to pick it up.
Transforming Southern Ocean Birds into Living Sensors “was a shot into the dark “, says den Uden. But as his team reported, it did work. While albatrosses flew over the cold waters between southern Africa and Antarctica, instruments in their backpacks recorded various sources of infrasound. This suggests that it is possible to listen to all sorts of distant sounds without resorting to the ground to place the detectors.