speaking of physics, interesting theory

i know this is not news to most people, but i reckon the more people who blog / post about it the better...

infrasound could well be the cause of many peoples' daytime "paranormal" experiences.

Tandy was working late in the "haunted" Warwick laboratory when he saw a gray thing coming for him. "I felt the hairs rise on the back of my neck," he said. "It seemed to be between me and the door, so the only thing I could do was turn and face it."* But the thing disappeared. However, it reappeared in a different form the next day when Tandy was doing some work on his fencing foil. "The handle was clamped in a vice on a workbench, yet the blade started vibrating like mad," he said. He wondered why the blade vibrated in one part of room but not in another. The explanation, he discovered, was that infrasound was coming from an extractor fan. "When we finally switched it off, it was as if a huge weight was lifted," he said. "It makes me think that one of the applications of this ongoing research could be a link between infrasound and sick-building syndrome." When he measured the infrasound in the laboratory, the showing was 18.98 hertz--the exact frequency at which a human eyeball starts resonating. The sound waves made his eyeballs resonate and produced an optical illusion: He saw a figure that didn't exist.