Sydney, Oct 15: Glowing globes of electricity or ball lightning have been around for centuries - but without any scientific explanation for their existence. Scientists in Australia have proposed a new theory -- that ball lightning is caused when leftover dense ions (electric energy) are swept to the ground following a lightning strike.
Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Australia National University scientists have come up with a new mathematical theory to explain how and why it occurs.
The new theory focuses on how ball lightning, which can last up to 20 seconds and occurs in houses and aeroplanes -- can pass through glass, the Journal of Geophysical Research Atmospheres reports.
Previous competing theories have cited microwave radiation from thunderclouds, oxidising aerosols, nuclear energy, dark matter, antimatter, and even black holes as possible causes, according to a CSIRO statement.
Led by CSIRO scientist John Lowke, the new theory proposes that ball lightning is caused when leftover ions (electric energy), which are very dense, are swept to the ground following a lightning strike.
Lowke proposes that ball lightning occurs in houses and aeroplanes when a stream of ions accumulates on the outside of a glass window and the resulting electric field on the other side excites air molecules to form a ball discharge. The discharge requires a driving electric field of about a million volts.
"Other theories have suggested that ball lightning is created by slowly burning particles of silicon formed in a lightning strike, but this is flawed. One of the ball lightning observations cited in this paper occurred when there was no thunderstorm and was driven by ions from the aircraft radar operated at maximum power during a dense fog," adds Lowke.
Lowke used eye-witness accounts of ball lightning by two former US Air Force pilots to verify the theory.
Former US Air Force lieutenant Don Smith recalls: "After flying for about 15 minutes, there developed on the radome (radar cover) two horns of Saint Elmo's fire. It looked as if the airplane now had bull's horns... they were glowing with the blue of electricity."