Study suggests mysterious global hum may originate in human hearing system

For nearly half a century, people across the world have reported hearing a low, persistent hum with no discernible source — a sound that arrives in silence and resists every attempt at explanation. Norwegian researchers now suggest that for many sufferers, the origin may lie not in the world outside, but within the auditory system itself, as a rare form of low-frequency tinnitus. The finding does not close the case entirely, but it offers something perhaps more valuable than a definitive answer: the quiet dignity of being believed.