Mysterious sounds coming from Mariana Trench - the deepest point on Earth were recorded long time back. The sounds were creepy and took everyone as surprize. Now, the piece of news is that the scientists claimed to have solved the mystery behind it as they say they have identified the source from where the alien sound came.
An autonomous vehicle had recorded the 3.5-second audio that was mysterious and creepy as hell. The sound was captured several times between 2014 and 2015. The challenge for the scientists was to find the source of the sound - whether natural or unnatural.
According to researchers from the Oregon State University, the source of the mysterious sound was a new type of baleen whale. The scientists came to this conclusion after months of analysis.
“It’s very distinct, with all these crazy parts,” said one of the team, Sharon Nieukirk from Oregon State University.
“The low-frequency moaning part is typical of baleen whales, and it’s that kind of twangy sound that makes it really unique. We don’t find many new baleen whale calls.”
While humans have an ability to hear between 20 and 20,000 Hz, the sound spanned frequencies as low as 38 hertz and as high as 8,000 hertz. So, the sound is within the audible range and covers a very broad frequency.
When in water, the waves of the sound travel big distances. Because the source can be kilometers away so it could be almost anything. Clueless about the start point, the researchers begin to eliminate possible sources. Firstly, they decided to eliminate those sounds that are man-made.
“The sounds reported here are not similar to known anthropogenic sources such as noise produced by ships or seismic airguns,” the team reports.
They then shifted to geological sounds but didn't find anything to fit the sound profile. So, lastly, only a biological source was left and it was a whale.
“They also do not resemble geophysical sources such as the very low-frequency sounds produced by earthquakes and ice, nor the sounds produced by wind or rain. … [We] hypothesise that these complex sounds were produced by a biological source.”
Though in the recorded history, these sounds are extremely unique, but Nieukirk discovered an equally bizarre sound from Australia’s Great Barrier Reef. That sound came from dwarf minke whale – the so-called Star Wars minke call.
Although it was different, but in terms of frequency and structure, it somehow had similarities to the Mariana Trench one.
“The complex structure of the Western Pacific Biotwang sound, the frequency sweep, and the metallic nature of the final part of this call are all very similar to characteristics of dwarf minke whale Star Wars calls,” the team concludes.
Even if this sound came from minke whales, the big questions still remain like - what kind of a call is it? The first option could be a mating call. But such calls are seasonal, and this sound was heard constantly.
“If it’s a mating call, why are we getting it year round? That’s a mystery,” says Nieukirk. “We need to determine how often the call occurs in summer versus winter, and how widely this call is really distributed.”
Another question is if something else, what it could be? Nieukirk says, good science will explain it.
“It really is an amazing, weird sound, and good science will explain it,” says Nieukirk.