Long thought to cause feelings of fear or awe, infrasound is sound that is able to cover long distances with little dissipation at a frequency too low to be detected by the human ear. It is created by natural phenomena such as ocean waves and earthquakes and can be artificially produced by explosions or machines. Infrasound is used by some animals to communicate over long distances and by predators to “freeze” their prey. Why do some scientists believe infrasound is related to ghost sightings? Discuss