Lightning isn't the kind of thing you want to see inside -- especially when it's a glowing orb ambling through the window and pulsing about. But that's exactly how ball lightning (purportedly) rolls. And according to the excellent HowStuffWorks article on the subject, such a seemingly freakish phenomenon isn't even all that rare: 30 out of 150 people believe they've seen it.
But ball lightning has also long inhabited the realm of sketchy science. No one's quite sure what causes it, and theories have chalked up the ephemeral orbs to St. Elmo's fire, plasma clouds or visible waves of electromagnetic radiation. According to Science Daily, some researchers have considered root causes like glowing dust balls or molten metal, while others have gone as far as to create "luminous fire balls" in the lab to get a personal look. A theory from John Abrahamson at the University of Canterbury in Christchurch, New Zealand, promisingly suggested the spherical lightning formed when silicon particles burning in the air created a chemical reaction. Truly out-there thinkers have chalked it up to aliens or miniature black holes.
Because of the wealth of scientific theories today, it's hard to even imagine a time when scientists weren't trying to figure out what ball lightning was. Sightings date back at least to the Middle Ages, maybe even to the ancient Greeks, but no single orb made it on record until the 18th century. That's when the unlucky Georg Richmann, a physicist performing electrical experiments, came head to head with ball lightning and died on the spot. (It could have been you, Ben Franklin!)
Perhaps Richmann's death scared everyone off for a century or so, because it wasn't until 1963 when ball lightning again commanded serious scientific attention. During a flight from New York to Washington, D.C., a physicist experienced ball lightning first-hand when it rolled down the aisle of the aircraft. His awe (and presumably his scientific credentials) started off a new wave of research involving the atmospheric phenomenon.
We've come a ways since then, though, and the latest theory on ball lightning is a little more cerebral than the ones listed above. I'll tackle it next week in a separate post.