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 16-foot wide spark of ball lightning. It glowed continuously for about 1.6 seconds and floated for a distance of some 50 feet.
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 energized 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 Elmo's fire have been reported 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 yards 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.