When Chinese astrophotographer Shengyu Li was setting up his camera and tripod to capture star trails, he unexpectedly saw something else entirely: a mysterious blue light emanating from an avalanche.
Li was at the foot of Mount Xiannairi in Sichuan on October 27 planning to capture a timelapse of the stars above when an avalanche happened, triggering the blue lights to flash on the mountain.
“We have not found any previously documented cases of such an event, making this discovery both thrilling and intriguing for us,” Li tells SpaceWeather.com. “Our initial hypothesis is that the luminescence may result from friction-induced lighting during the fragmentation of ice.”
The avalanche was caused by an icy serac breaking free from a hanging glacier which fragmented as it tumbled down the mountain. Carson Reid, a mountaineer, tells SpaceWeather.com that the blue lights appear when there is a significant “smash point”.
Triboluminescence
In a lengthy post on the social media platform X, a science communicator called Erica speculated that the blue lights were caused by a natural phenomenon known as triboluminescence.
On Oct. 27, Chinese astrophotographer Shengyu Li captured rare blue flashes during an avalanche on Mount Xiannairi, possibly caused by “triboluminescence”, light generated by friction during ice fragmentation.
Triboluminescence is a phenomenon where light is emitted when… pic.twitter.com/gTyerkvBvs
— Erika (@ExploreCosmos_) November 25, 2024
“Triboluminescence is a phenomenon where light is emitted when certain materials are fractured, scratched, or rubbed,” explains Erica.
“It occurs due to the breaking of chemical bonds or the sudden separation of surfaces, which can create electrical charges. These charges cause ionization of the surrounding air or excitation of the material itself, leading to visible light emission.”
For a simpler explanation, SpaceWeather.com quotes physicist Richard Feynman who explained that “when you take a lump of sugar and crush it with a pair of pliers in the dark, you can see a bluish flash. Some other crystals do that too. Nobody knows why.”
The Smarter Every Day YouTube channel demonstrated triboluminescence by smashing Life Savers candies with a hammer and filming it in super slow motion, see above.
Image credits: Photographs by Shengyu Li.