The mysterious hum heard around the world may finally have an explanation | ScienceDaily

Theory Briefing

• A phenomenon called The Hum has been reported globally for decades, yet standard acoustic instruments consistently fail to detect it.
• Competing theories range from human-made acoustic pollution to geological or atmospheric sources, with no consensus until now.
• A new explanation has emerged that may finally account for why only some people hear the persistent low-frequency drone.
• The Hum's selectivity — heard by a small fraction of any population — is central to the debate over whether its origin is physical or perceptual.