Scientists have discovered that the global low-frequency hum phenomenon, which has baffled residents of various countries for years, originates not from secret facilities or the ocean, but within the human auditory system itself, reports Science Daily, as cited by infohub.kz.
The phenomenon, known as "The Hum," has been recorded for decades in the United States, the United Kingdom, and other nations. Individuals describe a persistent low-frequency sound akin to an engine running, heard predominantly indoors at night, while others nearby may notice nothing. A research team led by Professor Marcus Drexel of the Norwegian University of Science and Technology tested 28 people who suffer from this experience.
Initially, the scientists checked whether these individuals possessed exceptional hearing capable of detecting distant vibrations from factories or ocean waves. That theory was confirmed for only two participants. Next, they measured spontaneous otoacoustic emissions—micro sounds produced by the inner ear itself—but this factor was also ruled out. Ultimately, the authors of the study, published in the journal PLOS One, concluded that in most cases, the global hum is a specific form of subjective low-frequency tinnitus (ringing in the ears). The person genuinely perceives this auditory system malfunction as an external stimulus.