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One hundred facts that are interesting but ultimately useless. |
Infrasound - natural phenomena / physics / physiology - Infrasound refers to soundwaves that occur below the range of human hearing (which usually bottoms out at a frequency of 20 Hz). It can have a variety of causes -- including vibrating machinery, earthquakes, ocean waves, and even some kinds of animal. While not technically audible, infrasound is still capable of causing resonance in the human body. Some known side-effects include nausea, feelings of dread or fear, or even visual hallucinations. Infrasound is thought to be the cause of many reported ghost sightings. #031 |