London, Dec 1 (ANI): Ball lightning - phenomena apparently witnessed by many - may be caused by space debris, suggests a new study.
Thousands of people have seen floating orbs of light, sometimes during thunderstorms, but their origin has never been established. And scientists believe that ball lightning was merely a hallucination caused by magnetic fluctuations during storms.
However, in 2006, Don Vernon, a farmer in Queensland, Australia, spotted two green balls descending from the sky even when the weather was clear.
Oddly, the second rolled down a hill, bounced over a rock and then vanished.
Observations by Stephen Hughes, an astrophysicist at the Queensland University of Technology in Brisbane, revealed that the first orb was probably a bright meteor caused by debris from Comet 73P, which came closer to Earth at that time than any other comet in 20 years.
The second, Hughes said, was ball lightning triggered by the meteor.
Hughes said it is possible such connections could create a wide range of strange phenomena and could be behind some hitherto unexplainable UFO sightings.
The cometary debris ionised the atmospheric gas it passed through, boosting the current that normally flows between the ionosphere - an electrically charged region in the upper atmosphere - and the ground, according to him.
When this "supercharged" conduit hit the soil, it formed a plasma ball, he argues. He said impacting space junk might also produce the effect.
"It is certainly plausible. It's almost impossible to prove anything with such an ephemeral event as this," New Scientist quoted John Lattanzio, an astrophysist at Monash University in Victoria, Australia, as saying.
"It's far more likely that the electrical current is coming from a thundercloud 5 kilometres above the ground, rather than a direct line to the ionosphere 100 kilometres away," said John Lowke, a ball lighting researcher at Australia's national science agency in Sydney.
The study appears in Proceedings of the Royal Society A. (ANI)