Seeing is believing, but what about hearing?
Since the 1970s, a small percentage of people all over the world have detected a mysterious sound just on the edge of their auditory range. Some folks describe it as a rumble, others like a car idling, still others like a pump operating in the far distance.
To the roughly 2% of the population who can hear it, The Hum (as it’s come to be known) is maddening. Not only does it have all the persistent annoyance of tinnitus, but people seeking relief from it often come up against disbelief on the part of the medical professionals they reach out to.
The Hum has been reported in the U.S., Australia, Canada, Germany, and Northern Ireland. The bulk of these mystery sounds were eventually explained away, thanks to the presence of nearby industrial facilities. But in the small town of Taos, New Mexico, The Hum still defies solid explanation.
The Taos Hum started getting media attention in the early 1990s when residents began to report about their auditory experiences there. Residents of New Mexico are used to living in relatively close proximity to government research facilities, so it’s no surprise they wanted to make sure they weren’t being exposed to anything dangerous. Eventually, they raised enough of a stink that the New Mexico state government took notice and tapped a group of researchers to investigate.
An investigation comes up dry
The team, led by Professor Joe Mullins, comprised a dozen scientists from Los Alamos National Laboratory, Phillips Air Force Laboratory, the Sandia National Laboratories, and New Mexico’s Health Sciences Center, among others.
The results were inconclusive, to say the least. The scientists set up highly sensitive microphones in areas where “hearers” claimed to have detected The Hum, but their instruments failed to record anything substantial. Mullins and his team also conducted extensive surveys of the Taos population, and played sample tones to hearers in an attempt to identify the frequency range they were experiencing.
Downtown Taos. Photo: Shutterstock
Characteristics of The Hum
Hearers of the Hum were evenly split between men and women, and middle-aged people were more likely to hear it than anyone else.
Sometimes The Hum was localized, meaning hearers were able to move away from it. Other times, hearers reported that no matter where they went in Taos and the surrounding area, The Hum followed. Most people reported hearing the Hum between 8 and 9 pm, and 80% of hearers perceived the sound at least once a week. One thing everyone had in common was matching The Hum to extremely low frequencies played by the scientists.
Tinnitus affects somewhere between 10 to 14% of the world population, so the easiest explanation is that once the story of the Taos Hum spread through the town, a fraction of tinnitus sufferers began attributing their condition to sources outside their inner ears.
But as Mullins later wrote in an article for The Acoustical Society, the experience of hearers doesn’t quite match those experiencing tinnitus.
“One problem with such an explanation is that tinnitus itself is not well understood,” Mullins stated, before going on to explain that tinnitus is a high-frequency experience, while The Hum hovers down in the extreme low-end of the frequency range.
“Furthermore, many hearers insist they can hear beats between their perceived tone and the objective tone generated in matching experiments. Beats have not been demonstrated reliably in matching experiments using subjects with tinnitus,” he continued. In other words, The Hum fluctuates, while tinnitus is consistent.
A possible explanation
In the absence of any nearby heavy industry that could explain the phenomenon, and with multiple generations of auditory specialists unable to record it, it would be easy to write The Hum off as a very specific example of New Mexican New Age woo, just another group of UFO-spotting, crystal-gazing, conspiracy-mongering desert dwellers with too much time on their hands.
But the fact remains that similar experiences have been reported all over the globe, and not all of them are easy to explain. The answer, according to Dr. David Baguley, head of audiology at Addenbrooke’s Hospital in Cambridge, might be a complex three-part blend of evolutionary adaptation, physiology, and psychology.
Evolution, Baguely explained to the BBC, has given many animals, including us, the ability to sharpen our hearing, particularly when stressed or excited.
“If you’re sitting by a table waiting for exam results and the phone rings, you jump out of your skin. Waiting for a teenager to come home from a party — the key in the door sounds really loud. Your internal gain is sensitized,” he said.
And some people, Baguely went on, are uniquely sensitive to sounds in certain ranges. Sounds so subtle that even microphones can’t easily pick them up.
Vicious cycle
Finally, it’s easy for a stressed-out brain to hyper-fixate on sensations.
“It becomes a vicious cycle,” Baguely said. “The more people focus on the noise, the more anxious and fearful they get, the more the body responds by amplifying the sound, and that causes even more upset and distress.”
Many animals have the ability to ‘hyper-fixate’ on sounds, especially when stressed or anxious. Photo: Shutterstock
This last part explains why hearers of the Taos Hum can’t seem to shake it once they perceive it for the first time. Like probing a loose tooth with a tongue, they can’t help but turn their internal gain all the way up once they detect it initially.
In any case, Baguely believes that at least some hearers in Taos and elsewhere are legitimately hearing something. The cause of The Hum likely varies from place to place, and the Taos Hum, in particular, remains, for now, unexplained.
The Bloop
But what about a mystery sound that was indeed captured by scientific instruments? Such is the case with The Bloop.
In 1997, a hydrophone array belonging to the U.S. government detected an ultra-low frequency sound originating from somewhere in the South Pacific Ocean. Give it a listen.
Now you understand why they call it “The Bloop,” right?
For almost a decade, scientists believed The Bloop was either an unusual sound emitted by a known marine species or a typical sound emitted by a heretofore unknown animal. The ocean, after all, is a very big, very unexplored place. The usual conspiracy theories about secret Russian subs and aliens also circulated on the still-young internet.
But as the years rolled on, scientists from the Pacific Marine Environmental Laboratory (PMEL) continued to place hydrophone arrays closer and closer to Antarctica. Their goal was to study undersea volcanoes, but in 2005, they caught The Bloop again — this time with enough instruments in place to triangulate an exact source.
The Bloop, as much as it presents as an organic sound, was in reality generated by ice cracking in an Antarctic glacier, causing an “icequake.” It’s not nearly as romantic as an undiscovered marine species, but still — science is cool.
Antarctic glaciers were responsible for The Bloop. Photo: Shutterstock
Other mystery sounds
In fact, glaciers, icebergs, and their movements have been attributed to a host of mysterious underwater sounds, with names like Julia, The Slow Down, and The Train. Here’s The Train, recorded by the National Oceanic and Atmospheric Administration (NOAA) in 1997.
According to NOAA, The Train “was most likely generated by a very large iceberg grounded in the Ross Sea, near Cape Adare. The sound is generated as the iceberg is slowly moving and dragging its keel on the seafloor.”
So far, every mystery sound we’ve discussed has been low-frequency, but there’s a final example from Canada’s extreme north that lives on the other end of the spectrum.
“The Ping” cropped up in Nunavut’s Fury and Hecla Strait in the summer of 2016. Lying off northwestern Baffin Island, the strait is often ice-choked and hard for ships to get through. Local ocean-going hunters in the area were able to detect this Ping through the hulls of their boats, and provincial officials recorded a noticeable drop in wildlife activity in the area over the summer.
Photo: Natural Resources Canada
Baffinland Iron Mines Corporation and Greenpeace conservation activity in the area were blamed. Both organizations and the Canadian government denied responsibility. Like The Hum, no one ever managed to record it.
A spokesperson for the Canadian Department of National Defense later told CBC that “Canadian Armed Forces are taking the appropriate steps to actively investigate the situation.”
Eventually, The Ping vanished, and its source is still a mystery.
