Monday, May 17, 2010

Ball Lightning Hallucination—Balls!

This illustration depicts the rare phenomenon of ball lightning. It appears on p. 55 of Wonders of Science Simplified (Metro Publications, New York, 1949) and shows a lightning ball erratically ricocheting around and, having descended the chimney, traverses the interior of a farmhouse and finally explodes.

When I was eight years old, my much older neighbor gave me his copy of this book—presumably because he recognized my interest in science was more intense than his own. I still have it and although I remember this picture well, I never thought I would see such a thing. I was wrong.

Years later, as a young teenager, my father and I were looking out of my bedroom window at the "fireworks" on display during a severe electrical storm. Like the illustration, my bedroom was on the second story of our house so, we had quite a panoramic view. It was late afternoon and a bit darker than normal because of the storm clouds. Two houses away, to the right of our view, was a street corner that formed a T-junction with the street where our house was located. At that same junction there was a church that had a lightning conductor on its steeple. After watching the storm for a while, some lights caught my attention in the trees opposite the T-junction. At first, I thought it was just headlights reflecting off the wet leaves of the trees as a car turned left into our street; eventually to pass in front of my bedroom window. But the round light kept going! As it separated from the trees with an apparent speed of a few feet per second, it became abundantly clear to both my father and me that it was not headlights. Nor did any car pass our house from the right, contrary to our expectation.

The light was a translucent, purplish-green color with the apparent diameter and shape of an oversized basket ball. Traveling more or less horizontally, it threw off sparks as it passed by (or possibly struck) chimneys of the houses below. My eyes were bugging out of my head in disbelief. The electric ball continued in an approximate straight line for about half a mile, until it disappeared in a flash among some tree tops in a local park. At the time, I didn't realize I was witnessing ball lightning but that quickly became the speculation after the event. The next day I rode my bike to the area in the park where I thought the fireball had disappeared. There, lying on the ground, were some scorched branches that had been torn off a large gum tree. Moreover, I could look back along a line of sight and see my house, as well as the church steeple where the fireball had probably originated. There is little doubt those branches were brought down by the ball lightning. We saw no other lightning strikes in that area during the storm. Luckily, the strange electric ball did not descend down anyone's chimney.

A recent article in New Scientist suggests that ball lightning may be an illusion due to the influence of magnetic fields on the brain's visual system. Like cancer, ball lightning is probably not a single phenomenon, but if what my father and I both saw (including the measurable evidence) was not ball lightning, then it was one hell of an optical illusion!