Infrasound consists of sound waves so low that humans cannot hear them, yet animals use them to communicate over vast distances.

Infrasound refers to sound waves with frequencies lower than 20 Hz, which is the bottom limit of human hearing. Because these waves have long wavelengths, they are less likely to be scattered or absorbed by obstacles like trees or buildings. This allows the sound to travel hundreds of kilometers without losing much energy.Elephants use infrasound at frequencies as low as 14 Hz to coordinate herd movements over distances of up to 10 kilometers. Research by Dr. Katy Payne in the 1980s first revealed that these low-frequency rumbles allow elephants to maintain social structures across vast landscapes. Similarly, blue whales emit infrasonic pulses that can travel thousands of kilometers through the ocean's deep sound channel.Humans can still be affected by these frequencies even if we do not hear them. A 2003 study led by Professor Richard Wiseman in London showed that infrasound can trigger feelings of anxiety, extreme sorrow, or chills in humans. This phenomenon is often cited as a scientific explanation for 'haunted' locations where high-power fans or traffic create low-frequency vibrations.In the field of geophysics, infrasound monitoring is a vital tool for global safety. The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) operates a global network of 60 infrasound stations to detect secret nuclear explosions. These same sensors can detect the acoustic signatures of volcanic eruptions, meteor strikes, and severe weather patterns long before they are visible to satellites.