Mysterious sound at the most remote point on the planet

Low-frequency sounds picked up by sonar equipment at Point Nemo, Pacific Ocean, in 1997 were once thought to be made by sea monsters.

Point Nemo in the South Pacific is considered the most remote place on the planet. When ships get there, they will be about 2,700 km from the nearest land. When the International Space Station (ISS) passes overhead, the station’s astronauts will be the closest to the sailors, only about 400 km away.

Because of its remote location, the currents there are few fish and fishermen rarely visit, Point Nemo has become a graveyard for old satellites and spacecraft. When the International Space Station (ISS) is decommissioned, expected to crash into the area around 2030, it will also crash. More than 263 pieces of space junk have sunk to Point Nemo since 1971, including Russia’s Mir station and NASA’s first space station, Skylab, according to a 2019 study.

It was at Point Nemo that the National Oceanic and Atmospheric Administration (NOAA) detected an extremely low-frequency sound in 1997. The strange sound was detected by sonar devices scattered across the Pacific Ocean and is among the loudest sounds ever recorded underwater. Experts call this sound a bloop. It was so loud that it was picked up by sonar devices up to 4,800 km away.

“There are a lot of things making noise down there. Whales, dolphins, fish, and the sounds of the Earth,” said NOAA oceanographer Chris Fox.

However, no known animal can produce the bloop. As a result, many theories have been put forward about the culprit, from giant squids to underwater dinosaurs to megalodon sharks to sea monsters. After all, more than 80% of the ocean has yet to be explored by humans. These theories became even more compelling when NOAA announced that the bloop was not man-made.

The Bloop has puzzled scientists for years. According to Fox, the mysterious sound may be related to the process of calving ice. "The sound always comes from the south. We suspect it is ice near the coast of Antarctica," Fox said.

It wasn’t until 2005, when NOAA conducted an acoustic survey of Antarctica, that scientists began to understand the origins of the bloop. By 2011, after all the data had been collected, they were able to clearly explain what the bloop was, says Robert Dziak, a specialist at NOAA’s Pacific Marine Environmental Laboratory. It was the sound of a glacial earthquake, which occurs when an ice shelf breaks off and breaks away from a glacier in Antarctica.

"Ice cracking is a prominent natural sound source in the Southern Ocean. Every year, tens of thousands of icequakes occur due to sea ice cracking, melting, and ice breaking off from glaciers and flowing into the ocean. These have very similar characteristics to bloops," Dziak said.

According to NOAA, the iceberg that created the bloop was most likely between Bransfield Strait and the Ross Sea, or Cape Adare in Antarctica. As climate change continues, NOAA warns that ice quakes could become more common.

Thu Thao (According to IFL Science, Business Insider )

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