From time to time, deep grumbling sounds, alternating with a series of high-pitched metallic pings, come from the depths of the 2,400-km-long Mariana Trench in the Pacific Ocean bed, which holds the deepest point of any ocean (11 km).
These mechanical sounds have perhaps been coming for centuries but were first heard by mankind in 2014.
What is it? A monster? An alien underwater civilisation? A secret operation, perhaps, by the US Navy?
It piqued scientific curiosity. Theories abounded, opinions differed. Some speculated that the sounds came from some deepwater animal species but others disagreed, given the mechanical quality of the sounds.
In 2018, a group of American scientists got down to work. They put in eight ‘drifting acoustic spar buoy recorders’ (DASBRs) — suspended vertically at a depth of 150 m — to record the sounds for two minutes every 10 minutes, and collected 1,807 hours of recordings. In 2021, they deployed 22 DASBRs and collected 4,405 hours of recordings.
Analysing this huge cache of data was impossible for humans, so they turned to AI for help — one created by Google.
It has now been determined that the sounds are emitted by the gigantic whale species Bryde’s whale, which can grow to be 17 m long and can swim to extreme depths.
Thanks for the information but it opens up another line of questioning: Why are these animals going to such depths and for what?
