August 20, 2013
Air Force Scientists Share Insights About Lab-Created Ball Lightning
Lee Rannals for redOrbit.com - Your Universe Online
Ball lightning is a phenomenon that has puzzled some of the best minds for generations, including Aristotle and Nikola Tesla. Now, scientists from the US Air Force Academy say they have some new insights into reproducing the rare form of lightning in the laboratory.
The phenomenon consists of a floating, glowing ball that drifts eerily through the sky and then explodes violently. It sometimes can injure people and damage buildings. Balls can range in size from a small pea to several feet in diameter, and they can glow for up to 10 seconds. Scientists wrote in the American Chemical Society's The Journal of Physical Chemistry A that they have developed better ways of producing ball lightning in a modern laboratory.
Scientists say ball lightning occurs only once in every million lightning bolts, so researchers had to produce artificial ball lightning in the laboratory to study the phenomena. They describe experiments that helped them create more effective ways of making ball lightning, which is essential in order to help scientists gain further knowledge about the rare event.
The team also describes techniques that could help to make the fireball last longer so that observations can continue. They developed a special video technique that reveals more information than ever before about the structure of the lightning balls and how they move.
"Ball lightning is used almost generically to describe phenomena seen in nature that aren't described by normal lightning, bead lightning or things like 'St Elmo's fire', or aurora. And likely it's not one thing but several things that have similar observables," US Air Force Academy study leader, Dr Mike Lindsay, told BBC.
Ball lightning has also been the source of some UFO sightings, according to Australia astrophysicist Stephen Hughes. He said a green UFO seen to hover over nearby mountains in 2006 was actually ball lighting. The astrophysicist believes fireballs from a meteor shower could have triggered an electrical connection between the upper atmosphere and the ground, providing energy for the ball lightning to appear above the hills.
In 2012, CSIRO scientist John Lowke published a mathematical solution explaining the birth of ball lightning and how it is capable of passing through glass. He said ball lightning occurs when leftover ions are swept to the ground following a lightning strike.
One famous account of ball lightning, known as 'St Elmo's fire', took place when a C-133A cargo plane was flying from California to Hawaii when the phenomenon took place inside the cockpit.
Lindsay warned in the paper that the team isn't exactly sure that what they are producing in the laboratory is the exact same phenomenon as ball lighting as seen in St Elmo's fire.
"I don't think what we've created is lightning, although the initial stages of the electrical discharge that produce this 'plasmoid' have many similarities to lightning. They're just electric arcs - in this case, electric arcs to the surface of this solution of electrolytes. And then what happens is this plasmoid emerges from it," Lindsay said. "It has many similarities, and it's clearly not similar to better known phenomena such as St Elmo's fire or bead lightning, which are well known and understood in nature."