Bloop: Since 1997, Navy sonar equipment has occasionally picked up a sound they think is coming from the South Pacific, about 1,000 miles off the coast of South America.
They don’t know what it is, but they think it’s alive.
The sound, detected by the Equatorial Pacific Ocean autonomous hydrophone array which uses U.S. Navy equipment originally designed to detect Soviet submarines, matches the audio profile of a living creature. There is no known animal that could have produced the sound, however, and if it is an animal it would have to be huge: much larger than even a whale according to scientists who have studied the phenomenon.
Some postulate that the sound may come from a huge and as-yet undiscovered species of octopus or squid. Others dispute this, pointing out that no known species of cephalopod have the physiology that would allow this type of sound to be produced. To date there has been no explanation for what it is, exactly, that could have produced the sound and most seem unwilling to rule anything completely out.