Ball Lightning Explained?

By R. Colin Johnson

January 22, 2007

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Ball lightning has mystified electricity researchers since Benjamin Franklin first flew his kite in 1752. The very next year, Russian scientist Georg Richmann was killed by ball lightning while flying a kite modeled on Franklin's experiment.

Since then, dozens of hypotheses have been offered to explain ball lightning, from Nikola Tesla's seminal 1904 treatise, The Transmission of Electrical Energy Without Wires, to the most recent explanation offered by University of Canterbury (Christchurch, New Zealand) professors John Abrahamson and James Dinniss, that ball lightning is just vaporized silicon.

Now researchers Antnio Pavo and Gerson Paiva of the Federal University of Pernambuco in Brazil claim to have verified the vaporized silicon hypothesis in their laboratory.

"Several years ago, I predicted that the University of Canterbury hypothesis could be tested in the lab, and now these Brazilian experimenters claim to have done it," said Graham Hubler, a physicist at the U.S. Naval Research Laboratory in Washington. "Heck, there will probably be kids making ball lightning in their science lab classes."

Here's the theory: Sand, or silicon dioxide (also called "silica") can be vaporized by a lightning strike in the presence of carbon, causing the short-lived, glowing, floating objects called "ball lightning." The theory maintains that the silicon vapor glows from the heat produced when it recombines with oxygen in the air. That, according to the hypothesis, maintains the ball shape due to condensing silicon on its outside surface that is bound by the electric charge of the lightning.

To test the hypothesis, Pavo and Paiva subjected a silicon substrate to a high-voltage arc with 140 amps of current. As they moved the electrodes apart, an arc vaporized the 350-micron-thick substrate, creating luminous orbs the size of a golf ball.

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