Entries with tag "sounds"

During the Cold War, the U.S Navy set up a system called SOSUS (the Sound Surveillance System). It's an array of underwater microphones positioned all around the world, which they used to track Soviet submarines by the sound of their engines. The microphones sit several hundred yards below the surface of the water, at a depth where sound waves become trapped in a layer of water known as the "deep sound channel." At this depth, a combination of temperature and pressure cause sound waves to keep traveling without being scattered by the ocean surface or seafloor. Nowadays, NOAA has expanded the concept, installing additional hydrophones in 1996, and using the array to record underwater sounds for scientific study in the fields of biology, seismology, etc.

Through the years, several unexplained and unidentified sounds have been recorded, some repeatedly. Today, I've been reading about them and listening to the sound clips provided by NOAA. It's kind of spooky.

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