Home | News

Ball lightning scientists remain in the dark

Ball lighting is still baffling, scientists admit in a new report. They think the wisdom of more than 10 fields of science will be needed to explain the bizarre effect.

Glowing spheres of ball lightning float above the ground for up to a minute, usually when thunderstorms are nearby. Eyewitness reports have often been dismissed as fantasy, but with around 10,000 sightings over the past few decades, scientists are now convinced that it really exists.

A new report from the UK's Royal Society gathers many previously unpublished sightings of ball lightning. One describes how a luminous ball left a hole the size of a basketball in a screen door as it entered a house in Oregon, then navigated down to the basement and wrecked an old mangle. In another, an 80-centimetre glowing blob bounced on a Russian teacher's head more than 20 times before vanishing.

But explaining the reports is extremely tricky. Ball lightning can shine as brightly as a 100-watt light bulb, but has no obvious power supply. It does not radiate heat, yet it can melt glass when it floats into windows.

A leading theory suggests that ball lightning forms when a lightning strike vaporises silica in soil. The silicon vapour condenses into a fine dust that is bound together by electrical charges into a floating ball, which would oxidise and glow (New Scientist magazine, 8 April 2000).

"I am confident at this stage that the answer lies in the general direction of chemical reactions with very finely distributed particles," says John Abrahamson, a chemical engineer at the University of Canterbury in Christchurch, New Zealand.

Another possibility is that air ionised by lightning could bind with water to create a hot ball of plasma with a cool water-and-ion coat.

But the new report says that none of the current theories tells the whole story. Ball lightning is probably the product of a family of different processes. Lab simulations of these processes can make mini ball lightning, but it is far smaller than natural versions and does not live nearly as long.

Spontaneous human combustion

"It is important to try and understand these things," says David Turner, a retired physical chemist in Maryland who has studied ball lightning for a decade. But he adds that diverse fields of science, from maser physics to inorganic chemistry, may be required to explain it.

Turner thinks ball lightning might cause the spooky movement of objects blamed on "poltergeists". Abrahamson adds that similar chemical processes could also account for spontaneous human combustion, rare cases of people inexplicably bursting into flames.

"This is circumstantial only, but the charring of human limbs seen in a number of ball lightning cases are very suggestive that this mechanism may also have occurred where people have had limbs combusted," says Abrahamson.

Scientists think that if they can understand ball lightning fully and make it in the lab, it might provide a new way to contain high-temperature reactions that are useful to industry.

Journal reference: Philosophical Transactions of the Royal Society A (vol 360)


This unusually wide ball lightning is 100 metres in diameter and was observed over five minutes in Queensland, Australia (Photo: Brett Porter)


Enlarge image


Latest news

Evolution's big bang: how life on Earth took offMovie Camera

20:00 01 March 2015


Volleyballene puts a new spin on buckyballs

11:00 01 March 2015


Google wants to rank websites based on facts not links

13:00 28 February 2015


To save the rainforest, let the locals take control

20:00 27 February 2015




© Copyright Reed Business Information Ltd.