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Saturday, November 18, 2017

Ball Lightening

    Whether lore is full of rare phenomenon. Amphibians raining from the sky happens when frogs, fish or small waterborne animals are caught in a waterspout. They are picked up and unceremoniously dropped off on land, assuming the waterspout ventures to shore. I remember once seeing a small fish in a puddle in my employer's parking lot after a thunderstorm.
     Then there are triple rainbows. While double rainbows are impressive, they're not that unusual. Triple rainbows are a big deal though because you can only see two of the rainbows with the naked eye; the third occurs behind you and is obscured by the sunlight. They are so rare that no convincing photographic evidence even emerged until 2011.
     A rare weather event also occurred in the Grand Canyon in 2014 when the entire basin of the giant canyon was fogged in. As the ground cooled after a hot day and cold, humid air rolled in, low stratus clouds filled the canyon from the ground up. The result? The 277-mile long, 18-mile wide and 1-mile deep canyon was completely filled with thick, foggy clouds.
     Another rare phenomenon is ball lightening. Some people have been skeptical of accounts of ball lightening. Were these balls actually lightning? The skepticism began to wane in 1963 when a group of scientists flying from New York to Washington, D.C., witnessed a blazing orb drift down the aisle and disappear through the rear of the plane. That began their research.
     While some people may believed they didn't exist, I know better. Many years ago during a thunderstorm when I was in elementary school a ball of lightening about the size of a basketball passed through the classroom window and exploded in a cloud of smoke. I also remember my father, who worked on the railroad, telling me of the time he saw a ball of lightening bouncing down the railroad track and exploding in a cloud of smoke.
     Ball lightning appears as glowing orbs that seem to occur during thunderstorms, usually following a lightning strike. These floating fireballs shine as brightly as a 100-watt light bulb and they can be white, yellow, orange, red or blue in color and are typically about the size of a small grapefruit, although sightings suggest they can range in size from golf ball to beach ball.  Emanating from the fireball are little tendrils that seem to jerk the ball around and they move slowly and erratically and are followed by smoke trails that form spirals around them. And after a moment, they disappear. There's no scientific explanation for balls of lightning, although there are several proposed theories.
     Speculations about the cause have ranged from the existence of standing waves of electromagnetic radiation to plasma clouds and from short-circuiting power lines to St. Elmo's Fire. While no theory has yet to explain ball lightning, a promising theory focuses on silicon.
     The most popular current theory, proposed by John Abrahamson at the University of Canterbury in Christchurch, New Zealand, suggests that ball lightning is the result of a chemical reaction of silicon particles burning in the air.
     When lightning strikes the ground, silicon that occurs naturally in soil combines with oxygen and carbon and turns into pure silicon vapor. As the vapor cools, the silicon condenses into a fine dust. The particles in this fine dust are attracted to each other by the electrical charge created by the lightning strike, binding together into a ball. The glow and heat come from the energy created as the silicon recombines with oxygen in the air. And once the silicon has burned out, the ball lightning disappears.
     This theory also suggests materials such as aluminum and iron metals may also cause the orbs, and that any atmospheric discharge, not necessarily lightning, may explain why ball lightning has been sighted near power poles, electrical fitters, and even active faults.
     Researchers Antonio Pavao and Gerson Paiva of the Federal University of Pernambuco in Brazil have been working with the silicon hypothesis and believe they have verified the theory with silicon substrate and a high-voltage arc. They applied 140 amps of electricity to silicon substrate, which vaporized the substrate and sometimes produced golf ball-sized fireballs.
     Also, two scientists at Tel Aviv University accidentally created ball lightning with a device they call a "microwave drill." This microwave drill was made from a 600-watt magnetron taken from a conventional kitchen microwave oven and a powerful microwave beam capable of penetrating solid objects. The tip of the drill aims the beam at a solid substance and creates a hot spot in the solid. When the drill is pulled away from the hot spot, the drag produces a fireball resembling ball lightning.
     Recently researchers from Zhejiang University in Hangzhou, China, have proposed that the bright glow of lightning balls is created when microwaves become trapped inside a plasma bubble. At the tip of a lightning stroke reaching the ground, a electron bunch can be produced, which in turn excites intense microwave radiation. The eerie orb-light glow is created when microwave radiation given off during a lightning strike becomes trapped inside a plasma bubble. While ball lightening usually appears during thunder storms, it has been know to form inside closed rooms and, as mentioned above, inside aircraft. Exactly how ball lightning seems to float through walls or windows, however, is still up for debate.

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