The Ghost in the Machine
A lab that felt haunted turned out to have a fan making sound too low to hear, which left people uneasy and seeing shapes.
What was reported
Vic Tandy, an engineer working in a laboratory in the English Midlands, kept hearing from colleagues that the place felt uncomfortable. Late one night he broke into a cold sweat, felt watched, and saw a grey shape at the edge of his vision that vanished when he turned to look.
The next day, with a fencing foil clamped in a vice, he noticed the blade vibrating on its own. He traced it to a newly fitted extractor fan that was producing a standing wave of infrasound, sound too low to hear, at about 19 Hz.
Explanations offered
In 1998 Tandy and Tony Lawrence published a paper, 'The Ghost in the Machine', suggesting that infrasound near 19 Hz can make the eyeball vibrate and cause unease, blurred vision and shapes at the edge of sight. Adjusting the fan stopped the effects. Later studies have found the effects of infrasound weaker and less consistent than first thought.
- When
- Published in 1998
- Where
- A laboratory in the West Midlands, England
- Witnesses
- The engineer Vic Tandy and his colleagues
- Status
- Partly explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.