For decades, a persistent low-frequency hum has been reported by millions of people worldwide, yet its source remains unexplained. Known simply as 'the Hum', this phenomenon is described as a constant drone, similar to a truck idling or an airplane overhead, that never fades. It affects roughly 4% of the global population, often causing headaches, dizziness, and sleeplessness.
The earliest reliable reports of the Hum date back to the mid-1970s in Bristol, England, where dozens of residents complained of a low rumble. Theories at the time pointed to industrial fans at a warehouse in Avonmouth, but the Hum persisted even after the warehouse was decommissioned. Similar reports have since emerged in Hythe, Plymouth, and most recently Swansea, with studies often inconclusive.
Scientific hypotheses range from natural causes to technological origins. Some scientists suggest ocean waves colliding with the seafloor, volcanic activity, or even the mating calls of fish, such as the male midshipman fish. Others propose that the Hum could be the result of electromagnetic resonance from lightning strikes or the jet stream interacting with electricity pylons.
Another theory links the Hum to modern infrastructure, such as gas lines, cell towers, or ultra-low frequency radio signals used to communicate with submarines. The Pentagon has even studied the 'microwave auditory effect' as a potential sonic weapon. The Hum's emergence in the last 50 years suggests it may be a byproduct of technological advances, highlighting our complex relationship with the constructed world.
