The Sound of the Northern Lights
People in the far north have long said the northern lights crackle and clap. Scientists didn't believe them.
What was reported
In Finland, Norway, Canada and other northern lands, people have long described sounds during strong displays of the northern lights: crackling, popping, clapping or a faint hiss. Scientists doubted it, because the aurora shines about 100 km up, where the air is too thin to carry sound to the ground.
Some suggested people were 'hearing' what they saw, a trick of the mind.
Explanations offered
In 2016, Finnish acoustics researcher Unto Laine recorded the sounds and located their source about 70 metres above the ground, not in the aurora itself. He suggested that during strong geomagnetic activity, electric charge builds up in a layer of air where temperatures invert, and discharges as small cracks and pops. The witnesses had been right.
- When
- Reported for centuries; recorded in 2016
- Where
- Fiskars, Finland, and the far north
- Witnesses
- People in Finland, Scandinavia and Canada
- Status
- Mostly 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.