Scientists accidentally capture ball lightning, proving it to be a true natural phenomena - not an optical illusion
ST Elmo's fire. Angels. Min-min lights. Eerie orbs in the sky have sparked wonder and fear for centuries. Now science admits they exist.
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ST Elmo's fire. Angels. Min-min lights. These eerie orbs in the sky have been reported for centuries. Now science admits they exist.
For decades such unidentified flying objects have simply been dismissed as optical illusions or "swamp gas".
Now science has no excuse.
Mysterious ball lightning has been captured on scientific equipment - albeit by accident.
Scientists in China were observing the lightning of a thunderstorm with a simple video camera paired with a spectrometer - a device that measures the components of light - to identify the materials that produced it.
They got lucky.
In 2012, in the Qinghai region, they recorded a 5m wide spark of ball lightning. It glowed continuously for about 1.6 seconds and floated for a distance of some 15m.
It's taken more than a year of lab work, but now the scientists from Northwestern Normal University in Lanzhou, China, think they know what caused the spooky apparition.
The spectrometer revealed the lightning contained traces of silicon, iron and calcium. These elements were all present in the soil of the area.
The idea is a normal bolt of lightning struck the ground, blasting a cloud of energised soil nanoparticles into the air. These charged particles can coalesce into balls or collect around non-conducting objects while emitting the eerie light so well known to mythology.
Glowing lights known as St Elmos' fire have been repoted clinging to items such as the masts of ships for centuries.
Australia's Aborigine's call the balls of light they have seen bounding across the landscape Min-min lights.
In its ball form, the spooky form of lightning is said to range in size from a golf ball through to several metres across.
One of the first known sightings dates from Ancient Greece. References to glowing orbs in the sky are even found in ancient texts such as the bible's account of Elijah ascending to heaven in a fiery chariot.
Sometimes it's said to be harmless: In the 1960s a US Air Force pilot reported a strange glow of St Elmo's fire about his radar cover shortly before a ball of lightning materialised inside the cockpit. He was flying in fog at the time.
Other times, it's more malicious. One account from 1936 tells of how a "large, red hot ball" entered a house, burning through telephone wires and a window frame before dousing itself in a tub of water.
Many sightings report the mysterious orbs end with a loud "bang".
It was only in August last year that researchers in Colorado produced bright-white plasma balls in the lab. Formed from electric sparks and electrolyte solutions, the US Air Force scientists were not convinced this was the same ball lightning that was being reported in nature.
In December 2012, a team of Australian CSIRO scientists published a study stating ball lightning may be an accumulation of ions on a nonconducting surface - such as a window.
But the idea that ball lightning may be caused by lightning striking soil, turning it into vapour which condenses into a floating glowing ball, was first postulated by New Zealand scientist John Abrahamson in 2000.
Abrahamson told New Scientist magazine that the Chinese observation "is gold dust as far as confirmation goes."
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