The Whistlers in the Wires
During the First World War, soldiers eavesdropping on enemy telephone lines heard eerie falling whistles, like shells flying overhead, coming from nowhere.
What was reported
During the First World War, signals troops used sensitive amplifiers to listen in on the enemy's field telephones. Some of them heard strange whistling tones that slid down from high to low over a second or two, and soldiers joked that they could hear the grenades flying.
In 1919 the Dresden physicist Heinrich Barkhausen described the sounds, but couldn't explain them. Radio listeners have heard them ever since, on quiet nights, along with a rising 'dawn chorus' of chirps that sounds like birdsong.
Explanations offered
They are 'whistlers', radio waves made by lightning. Part of a lightning flash's energy travels out along the Earth's magnetic field lines, far into space and back down on the other side of the planet. On the way, the higher tones arrive first and the lower ones later, stretching the crackle of lightning into a falling whistle. Anyone with a simple receiver far from power lines can hear them.
- When
- Described in 1919
- Where
- Dresden, Saxony, Germany
- Witnesses
- Soldiers listening in on enemy phone lines, and radio listeners since
- Status
- 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.
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