Scientists have observed ball lightning for the first time in nature.
Ball lightning is pretty much literally what it sounds like - a sphere of electrical light which appears in the sky during a lightning storm.
Until the 1960s it was not widely believed to really exist, though stories of the phenomenon were recorded around the world, and even blamed for some deaths.
But even as the phenomenon started to gain traction - and was eventually created in the lab, it has never been observed in nature and caught on film.
Until now, that is. Chinese researchers have published a new study in the journal Physical Review Letters in which they say they recorded ball lightning during a storm in Qinghai - and have the evidence to back it up.
Jianyong Cen, Ping Yuan, and Simin Xue used spectrographs and video cameras to record the amazing sight of a ball of lightning rising five metres above the ground, and moving 15 metres before disappearing.
The sighting appears to lend weight to a theory proposed in 1999 that when lightning hits the ground, it stores energy in silicon nanoparticles which are forced into the air by the intense heat of the strike. They are then oxidised, release their energy and glow in a ball of pure silicon vapour.
The scientist behind that theory, John Abrahamson, a chemist at the University of Canterbury in New Zealand, told New Scientist the video of the strike was "gold dust".
"Here’s an observation which has all the hallmarks of our theory," he told the magazine.
“I think that this is a unique observation that is probably of ball lightning, or one type of ball lightning,” added lightning specialist Martin Uman of the University of Florida. “There have been many research programs that routinely video or photograph natural and triggered lightning,” he says, “but none, as far as I am aware, has stumbled on a ball lightning.”