- People have reported a mysterious humming sound around the world since the 1970s. It’s called The Hum.
- Scientists have proposed possible explanations. But there may not be a single answer for the phenomenon.
- The Hum might originate from human-made sources or nature. Sometimes, it might even originate within the hearers’ own ears or heads.
The Hum is weird and mysterious
Have you ever been bothered by a strange humming sound you couldn’t identify? Many people have. Scientists call it simply The Hum. It’s a low-frequency sound, sometimes felt as a vibration. People have heard it both indoors and outdoors, especially at night. An estimated 2-4% of the world’s population has heard it. That’s some 250 million people! And it’s been going on for decades, at least, with still no firm answer as to the source.
And now researchers at the University of Munich in Germany and the Norwegian University of Science and Technology in Norway have provided a scientific update on the mystery, published in the peer-reviewed journal PLOS One on March 27, 2026.
And science writer Idun Haugan has written about the phenomenon and the new study in the June 2, 2026, Norwegian SciTech News.
Haugan isn’t one of the researchers … but she’s heard The Hum herself. She said that theories about it are wide-ranging, from both human-produced and natural sources, to wilder conspiracy theories. Or even sounds produced by the human ear itself.
Feed: "Norwegian SciTech News"By: Idun Haugan on Tuesday, June 2, 2026
— Longtail News (@longtail-news.bsky.social) 2026-06-03T11:03:10.180954+00:00
1st and global instances of The Hum
So when did this unusual phenomenon first begin to be reported? As noted in Haugan’s article, the first known cases were in Bristol, England, in the 1970s. At the time, the theory was that large industrial fans were to blame. They were in the warehouse of a large department store. But a few years later, the store closed … and The Hum continued.
And The Hum didn’t stay in Bristol. People later said they heard it elsewhere in the U.K., including Hythe, Plymouth, Southampton, Swansea and even London. But scientists still didn’t know what was causing it.
Since then, The Hum has been heard in many other locations. People reported it in the U.S. in the 1990s. Taos, New Mexico and Kokomo, Indiana, are the first known locations. And then it went global. The unusual sound popped up in Canada, Australia, New Zealand, South Africa and several cities in Europe, including Oslo, Norway.
Most often, people report it in densely populated areas.
The Taos Hum was called the Ultimate Hum in the 1990s. Two percent of the population could hear it, with frequencies between 32 and 80 Hertz.
The Hum World Map and Database Project
In 2012, Glen MacPherson in Canada started the The World Hum Map and Database Project. He had previously heard The Hum himself when he lived on the West Coast. But when he relocated to another city, still on the West Coast, he no longer heard it. As Haugan mentions:
He became so interested in the sound phenomenon that he started the interactive The World Hum Map and Database Project in 2012, which collects data from places and people where the sound has been noted.
Various theories
Scientists have offered many theories for the phenomenon. These include both human-made and natural sounds. And of course, there are the usual conspiracy theories, too: in this case, aliens or the CIA.
Human technology can make various low-frequency sounds. Some examples are ventilation systems, heat pumps, traffic noise and windmills. Another is high-pressure gas pipelines. In nature, waves and wind can also produce these sounds.
Even the jet stream was suggested as a cause in 1973. But that was quickly dismissed as “absolute nonsense.”
But why does this particular hum seem to stand out? Why did it seemingly begin in one place and then expand to other locations. Or was it there before and just not noticed?
As noted by Haugan in her Norwegian SciTech News article, the new study began in Germany in an attempt to find answers. She wrote:
The Hum has attracted the interest of hearing and audiology researchers worldwide. Markus Drexl, an NTNU professor [working in neuromedicine and balance disorders], is among this self-selected group. He and two Ph.D. research fellows and a postdoc have conducted a study of 28 people in Germany who experience hearing an unexplained buzzing or humming.
2 main hypotheses
For the study, the researchers tested two hypotheses. The first is that The Hum can be measured in both human-made infrastructure and in nature. These are sounds that can be measured. Markus Drexl explained:
We know that there are people who hear low-frequency sounds that can actually be measured, even if other people don’t hear them. But it’s not so easy to find the source of these sound waves, because it’s a struggle to localize low-frequency sounds.
The researchers tested the 28 study participants to see if they had exceptionally good hearing. Only two of them had better than average gearing at low frequencies. Drexl told Idun Haugan:
Even though the group we tested was small, it still means that the hypothesis of having especially good hearing for low-frequency sounds does not hold for most people.
Low-frequency tinnitus?
Another possibility suggests some people might have a kind of low-frequency tinnitus. Tinnitus is an internal sound in the ear or head. It is commonly known as “ringing in the ears.” Many people experience it. But these sounds can’t be measured objectively.
So it’s possible that some people who hear The Hum might actually have a form of tinnitus. Drexl said:
Based on our results, although we haven’t ruled out cases of physical external sound sources, we suggest that subjective tinnitus in the low-frequency range is often the cause of hearing pulsations of low-frequency sound perceptions.
Coming from inside our own heads?
Our ears can hear sound. And they can also produce sound as well. The cochlea in the inner ear produces weak sounds. These sounds have different frequencies, but are typically between about 500 and 5000 Hertz. Could that be an explanation for The Hum? As Drexl noted to Haugan:
Most of us don’t hear these sounds. However, a few people can actually hear the sounds that the ear itself produces. And these sounds can be measured objectively.
One hypothesis was that the participants in our group could hear oto-acoustic emissions at low frequencies. That’s why we tested whether they had them.
But the results of the testing for that hypothesis was negative.
The human auditory system
Before we can figure out The Hum, Drexl thinks, we need to understand more about the human auditory system overall. He told Idun Haugan:
What we know about the hearing system is mainly based on how we capture and process sound with higher frequencies. We know less about how the auditory system handles and processes low-frequency sound, or infrasound.
If we want to conduct a thorough assessment of low-frequency sounds and infrasound, we first need a better understanding of how sensory systems process low-frequency sound and infrasound.
Have you ever heard this unusual hum or anything similar? Tell us in the comments below!
Bottom line: For decades, people around the world have reported hearing The Hum. What is it? A new study helps narrow down possible answers.
Source: On the potential sources of a low-frequency sound percept that only a few can perceive
Read more: 7 weird things space does to the human body
The post What is The Hum? Scientists provide an update first appeared on EarthSky.
from EarthSky https://ift.tt/0f1vO4Y
- People have reported a mysterious humming sound around the world since the 1970s. It’s called The Hum.
- Scientists have proposed possible explanations. But there may not be a single answer for the phenomenon.
- The Hum might originate from human-made sources or nature. Sometimes, it might even originate within the hearers’ own ears or heads.
The Hum is weird and mysterious
Have you ever been bothered by a strange humming sound you couldn’t identify? Many people have. Scientists call it simply The Hum. It’s a low-frequency sound, sometimes felt as a vibration. People have heard it both indoors and outdoors, especially at night. An estimated 2-4% of the world’s population has heard it. That’s some 250 million people! And it’s been going on for decades, at least, with still no firm answer as to the source.
And now researchers at the University of Munich in Germany and the Norwegian University of Science and Technology in Norway have provided a scientific update on the mystery, published in the peer-reviewed journal PLOS One on March 27, 2026.
And science writer Idun Haugan has written about the phenomenon and the new study in the June 2, 2026, Norwegian SciTech News.
Haugan isn’t one of the researchers … but she’s heard The Hum herself. She said that theories about it are wide-ranging, from both human-produced and natural sources, to wilder conspiracy theories. Or even sounds produced by the human ear itself.
Feed: "Norwegian SciTech News"By: Idun Haugan on Tuesday, June 2, 2026
— Longtail News (@longtail-news.bsky.social) 2026-06-03T11:03:10.180954+00:00
1st and global instances of The Hum
So when did this unusual phenomenon first begin to be reported? As noted in Haugan’s article, the first known cases were in Bristol, England, in the 1970s. At the time, the theory was that large industrial fans were to blame. They were in the warehouse of a large department store. But a few years later, the store closed … and The Hum continued.
And The Hum didn’t stay in Bristol. People later said they heard it elsewhere in the U.K., including Hythe, Plymouth, Southampton, Swansea and even London. But scientists still didn’t know what was causing it.
Since then, The Hum has been heard in many other locations. People reported it in the U.S. in the 1990s. Taos, New Mexico and Kokomo, Indiana, are the first known locations. And then it went global. The unusual sound popped up in Canada, Australia, New Zealand, South Africa and several cities in Europe, including Oslo, Norway.
Most often, people report it in densely populated areas.
The Taos Hum was called the Ultimate Hum in the 1990s. Two percent of the population could hear it, with frequencies between 32 and 80 Hertz.
The Hum World Map and Database Project
In 2012, Glen MacPherson in Canada started the The World Hum Map and Database Project. He had previously heard The Hum himself when he lived on the West Coast. But when he relocated to another city, still on the West Coast, he no longer heard it. As Haugan mentions:
He became so interested in the sound phenomenon that he started the interactive The World Hum Map and Database Project in 2012, which collects data from places and people where the sound has been noted.
Various theories
Scientists have offered many theories for the phenomenon. These include both human-made and natural sounds. And of course, there are the usual conspiracy theories, too: in this case, aliens or the CIA.
Human technology can make various low-frequency sounds. Some examples are ventilation systems, heat pumps, traffic noise and windmills. Another is high-pressure gas pipelines. In nature, waves and wind can also produce these sounds.
Even the jet stream was suggested as a cause in 1973. But that was quickly dismissed as “absolute nonsense.”
But why does this particular hum seem to stand out? Why did it seemingly begin in one place and then expand to other locations. Or was it there before and just not noticed?
As noted by Haugan in her Norwegian SciTech News article, the new study began in Germany in an attempt to find answers. She wrote:
The Hum has attracted the interest of hearing and audiology researchers worldwide. Markus Drexl, an NTNU professor [working in neuromedicine and balance disorders], is among this self-selected group. He and two Ph.D. research fellows and a postdoc have conducted a study of 28 people in Germany who experience hearing an unexplained buzzing or humming.
2 main hypotheses
For the study, the researchers tested two hypotheses. The first is that The Hum can be measured in both human-made infrastructure and in nature. These are sounds that can be measured. Markus Drexl explained:
We know that there are people who hear low-frequency sounds that can actually be measured, even if other people don’t hear them. But it’s not so easy to find the source of these sound waves, because it’s a struggle to localize low-frequency sounds.
The researchers tested the 28 study participants to see if they had exceptionally good hearing. Only two of them had better than average gearing at low frequencies. Drexl told Idun Haugan:
Even though the group we tested was small, it still means that the hypothesis of having especially good hearing for low-frequency sounds does not hold for most people.
Low-frequency tinnitus?
Another possibility suggests some people might have a kind of low-frequency tinnitus. Tinnitus is an internal sound in the ear or head. It is commonly known as “ringing in the ears.” Many people experience it. But these sounds can’t be measured objectively.
So it’s possible that some people who hear The Hum might actually have a form of tinnitus. Drexl said:
Based on our results, although we haven’t ruled out cases of physical external sound sources, we suggest that subjective tinnitus in the low-frequency range is often the cause of hearing pulsations of low-frequency sound perceptions.
Coming from inside our own heads?
Our ears can hear sound. And they can also produce sound as well. The cochlea in the inner ear produces weak sounds. These sounds have different frequencies, but are typically between about 500 and 5000 Hertz. Could that be an explanation for The Hum? As Drexl noted to Haugan:
Most of us don’t hear these sounds. However, a few people can actually hear the sounds that the ear itself produces. And these sounds can be measured objectively.
One hypothesis was that the participants in our group could hear oto-acoustic emissions at low frequencies. That’s why we tested whether they had them.
But the results of the testing for that hypothesis was negative.
The human auditory system
Before we can figure out The Hum, Drexl thinks, we need to understand more about the human auditory system overall. He told Idun Haugan:
What we know about the hearing system is mainly based on how we capture and process sound with higher frequencies. We know less about how the auditory system handles and processes low-frequency sound, or infrasound.
If we want to conduct a thorough assessment of low-frequency sounds and infrasound, we first need a better understanding of how sensory systems process low-frequency sound and infrasound.
Have you ever heard this unusual hum or anything similar? Tell us in the comments below!
Bottom line: For decades, people around the world have reported hearing The Hum. What is it? A new study helps narrow down possible answers.
Source: On the potential sources of a low-frequency sound percept that only a few can perceive
Read more: 7 weird things space does to the human body
The post What is The Hum? Scientists provide an update first appeared on EarthSky.
from EarthSky https://ift.tt/0f1vO4Y
