What is the SOFAR channel and how does it carry sound across entire oceans?
There is a hidden layer in the ocean where sound can travel 25,000 kilometers without fading - whales discovered it millions of years before we did.
The answer
The SOFAR (Sound Fixing and Ranging) channel is a horizontal layer in the ocean at roughly 600 to 1,200 meters depth where sound travels at minimum velocity. Sound waves entering this channel are continuously refracted back toward the center, becoming trapped in a natural waveguide that can transmit signals across entire ocean basins with minimal energy loss. A 10-kilogram explosive charge detonated in the SOFAR channel off Australia was detected near Bermuda - over 19,000 kilometers away. The US Navy discovered this phenomenon in the 1940s for submarine detection. Fin whales and blue whales produce low-frequency calls between 10 and 40 Hz that propagate through the SOFAR channel, potentially communicating across hundreds of kilometers.
Source: Wikipedia
- SOFAR channel
- ocean acoustics
- underwater sound
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