The mystery of the worldwide hum may finally be solved
Researchers are close to identifying the source of unexplained humming reported globally.
1A mysterious phenomenon
People in different parts of the world report hearing an unexplained humming sound with no identifiable source. This sound often becomes more noticeable at night and can cause physical discomfort in some individuals. First reported in the 1970s in England, the phenomenon has since been observed in many countries.
2A global research subject
Canadian teacher Glen MacPherson launched the World Hum Map and Database Project in 2012 to collect reports of hum experiences and location data. Researchers believe the phenomenon could have both natural and artificial sources, evaluating possibilities ranging from ocean waves to industrial equipment.
3Hearing experts investigate
Professor Markus Drexl from the Norwegian University of Science and Technology and his team studied 28 individuals in Germany. They tested whether participants had special sensitivity to low-frequency sounds. Results showed most people didn't possess extraordinary ability in detecting such sounds.
4The inner ear sounds theory
Researchers considered whether natural sounds produced by the inner ear (otoacoustic emissions) might explain the hum. However, tests didn't confirm this hypothesis. These sounds, normally in the 500-5000 Hertz range, weren't sufficient to account for the low-frequency hum.
5Low-frequency tinnitus possibility
Drexl suggests low-frequency tinnitus (ringing in the ears) might explain many cases. Tinnitus occurs when a person perceives sound without an external source. This condition can become a persistent discomfort for some individuals.
6The search for answers continues
Researchers continue their work to precisely identify the hum's source. Understanding this phenomenon could improve quality of life for affected individuals and provide new insights into environmental noise pollution and hearing health.