The research team, from the National Oceanic and Atmospheric Institute's (NOAA’s) Pacific Marine Environmental Laboratory (PMEL) was on a Voyage to the South Pacific in 1997. They were listening through hydrophones for sounds that would indicate underwater volcano activity.
All of a sudden, the scientists heard what they described as a "Bloop." It was a sound not only heard in the South Pacific over hydrophones. It was picked up by other underwater listening stations as far as 3,000 miles away.
A "Bloop?" Really? It was most unusual. And scientists, being scientists, crave the unusual and can't resist trying to solve a mystery.
As unscientific as that seems, the researchers on the ship and dozens of other scientists around the globe spent a significant portion of their careers trying to solve the mystery.
“It’s unusual when a sound is recorded on all of the sensors we have deployed,” said NOAA Acoustics Program manager Robert Dziak. “If it’s a ship, or a whale, when it makes a sound in the ocean, it isn’t big enough to be recorded all the way across the Pacific. But this sound was recorded on so many hydrophones, so it stood out in our mind as being something unique.”
The sound sent imaginations spiraling. The frequency profile of “the Bloop,” as it came to be called, roughly matched that of a living creature’s call, which immediately raised a staggering question. What could possibly be large enough to produce a sound detectable over 3,100 miles away? A blue whale, the largest known animal on Earth, can be heard across vast stretches of ocean, but the Bloop’s amplitude suggested something far bigger, perhaps twice that size. Earth’s oceans remain mostly unexplored, and scientists believe they still contain many undiscovered species. The coelacanth, for instance, was long believed to have died out 66 million years ago. It was known only through its fossils, until one turned up alive in a fisherman’s net in 1938. If a “living fossil” could hide in the deep for eons, what else might be down there? Some wondered whether an ancient ocean giant like the Megalodon or something even more gargantuan was still hunting in the abyss.
Some researchers posed the theory (tongue in cheek) that it may have been Cthulhu, H.P. Lovecraft's fearsome beast, part octopus, part man, and part dragon, that now sleeps inside the sunken, prehistoric city of R'lyeh. Curiously, Lovecraft devotees have placed the sunken city's coordinates about 1,500 miles from where the "Bloop" sound was traced.
What did you expect? Lovecraft? They are nerds.
What made the "Bloop" so curious was that scientists surmised from the sound's signature that it was biological. Did some immense beast, at least twice the size of a blue whale, the largest creature ever to inhabit the Earth, make a noise heard across the South Pacific?
The biological signature was of a very low frequency, which is why it was able to travel so far. Whale songs can also travel thousands of miles. It's believed that before the age of steamships and modern diesel-powered vessels, some whale songs, specifically those of humpback whales, could circumnavigate the globe.
But this was far more powerful than the sound any earthly creature could make. "It wasn’t until 2005 that they were finally able to confirm the source as an ice quake," reports Popular Mechanics.
As glaciers fracture and enormous chunks of ice break off (a process that’s been accelerating with global warming), they make noises that could be mistaken for mythical sea monsters. Broad spectrum sounds eerily similar to the Bloop include calving, the actual cracking of ice, and iceberg harmonic tremors, which are generated when icebergs scrape against the seafloor or each other.
Whichever iceberg was responsible for the BLOOP heard around the world, or at least the Pacific, was never identified. The amplitude of ice quakes makes them detectable on multiple sensors, even at distances over 3,100 miles. NOAA experts figured out that the direction this sound was coming from indicated that said glacier was probably somewhere between Bransfield Straits and the Ross Sea. Also in the Ross Sea, Cape Adare, a cape of black basalt which lies to the east the Antarctic Continent, is known for strange cryogenic noises and could have also been the source. Sounds that qualify as the spawn of the Bloop have also been heard through NOAA hydrophones in the Scotia sea.
It may not be an awakened Cthulhu, "But the Bloop still tells a story about something massive, ancient, and powerful," says Popular Mechanics. I would have settled for a Megalodon of a dragon.
