infrasound is silent but can cause anxiety, fear, mood swings, extreme sorrow, blurred vision, and chills. some scientists think it's present in haunted houses. it's been used to detect hurricanes, meteor blasts and volcanic eruptions; have been used in the Cold War, concerts, and churches; and by elephants, giraffes, rhinoceros, and whales. i'm still wondering why infrasounds are present in haunted houses........ (via kurzweilAI)