Colossal Octopus by Pierre Denys de Montfort

We’re approaching the 12th anniversary of ‘The Bloop’, an ultra-low frequency sound detected multiple times throughout the summer of 1997. The sound, heard on multiple sensors over 3000 miles apart, was recorded an exists here. Based on the frequency, scientists have determined the tentative creature (The Bloop is believed to be biological in origini) to be larger than the blue whale. How are the sounds recorded? An old article explains:

The listening stations lie hundreds of yards below the ocean surface, at a depth where sound waves become trapped in a layer of water known as the “deep sound channel”.

Here temperature and pressure cause sound waves to keep travelling without being scattered by the ocean surface or bottom.

Most of the sounds detected obviously emanate from whales, ships or earthquakes, but some very low frequency noises have proved baffling.

Scientist Christopher Fox of the U.S. National Oceanic and Atmospheric Administration’s Acoustic Monitoring Project at Portland, Oregon, has given the signals names such as Train, Whistle, Slowdown, Upsweep and even Gregorian Chant.

Most of these sounds have, in fact, been identified as geological noises. The Bloop, on the other hand, remains a mystery. One hypothesis is that the beast is a cross between the Kraken and a very large Mermaid. Considering neither has been discovered, no one can say such an assumption is false.