A very unusual event has caused quite a stir for some people that reported hearing an odd hum, and the worldwide hum fell into legend.
There are the cities that never quite sleep, even though nights are a little bit slower, fewer cars in traffic, and many people are off to bed. For some, the calmness of night only serves to bring into focus a maddening droning sound that keeps them awake.
Noise and conspiracy
1978 in the English city of Bristol, hundreds of people started hearing this sound. Many complained to the council about this disturbing noise that kept them up and seemed to be louder at night. No explanation had been found, the source never uncovered.
Some possible explanations alluded to noises from factories, tinnitus, or electricity pylons. Some more conspiratory minds pointed to flying saucers or undeclared military activities. Then, just as soon as it had begun, it stopped. Soon after, other people around the world began hearing it as well.
Mapping the worldwide hum
This strange sound has been described by hearers as a low-pitched noise, similar to an idling truck in a parking lot, and has come to be known as the worldwide hum. It has usually been reported by those who can hear it, in urban areas. Not everyone can hear it, hence why it poses such a mystery and not everybody believes it is actually happening.
The fact of the matter is that those who claim to hear it, are also plagued with various symptoms and are rendered uncomfortable by it. Some have experienced insomnia and sleep deprivation, others got headaches, dizziness, and irritability.
Not being able to drown out the annoying sound or find its source, deepens the frustration. After hearing the hum himself, Glen MacPherson from Canada created an online map in 2014, where anyone that also hears the hum can mark the location on the map.
Possible explanations for the worldwide hum
There are a number of possible explanations that have been outlined over the years. We do live in a world of technology and have lived ever since the industrial revolution, so mechanical whirls and hums from all manner of devices, electrical wiring, and generators, are plausible candidates.
While some noises have been linked to mechanical machines, such as the hum from West Seattle which was linked to a vacuum pump from cargo ships, others have not reached a clear industrial explanation.
A medical condition called tinnitus has also been considered, where a person might experience a ringing or humming sound, but the cause is internally generated by the nervous system, with no external catalyst. Otoacoustic emission is another sound generated by human ears, that can be too loud in some and cause discomfort.
The planet itself makes permanent free oscillations, that are not tied to seismic activity or earthquakes, and some people might be hypersensitive to it. Weather factors like storms swirling the oceans or waves beating the seafloor were also taken into account.
No conclusive explanation has been found until today, and the worldwide hum still makes itself heard by about 2 to 4 percent of the global population. Whatever the explanation to it might be, it is clear that some people hear some kind of noise and it is toiling with their lives. The mystery of the hum still looms over the planet and only the future might possibly come up with some answers or relief. Until then we are left to wonder what is causing it.