Last week's post on ball lightning covered the basics -- sightings, reports and deaths chalked up to the glowing orb. But what if some of those same occurrences were really just hallucinations? While Georg Richmann, ball lightning's unlucky 18th-century victim, might still argue for his case in particular, other, less tactile sightings could prove harder to back up.
According to a recent study by Joseph Peer and Alexander Kendl at the University of Innsbruck in Austria, ball lightning might be all in your head. Their paper, which was published on a physics research Web site and covered by National Geographic News, sprang from a pattern in ball lightning sightings: Most reports come during storms with a lot of electrical activity. Lightning strikes that hit in rapid succession can form magnetic fields, something that could conceivably stimulate the human brain and result in visions.
Since you can't very well place a research subject in the middle of a storm and hope he gets back to you, Peer and Kendl turned to the existing work of other scientists. Fortunately, a machine called the transcranial magnetic stimulator (TMS) is able to produce dramatic shifts in strong magnetic fields similar to lightning but without the danger. Subjects in the earlier experiments had these lab-created magnetic fields focused on their brains' visual cortex. With the power trained on the center of sight, subjects reported seeing illuminated discs and lines of white or gray that moved with the field's focus. Sounds suspiciously like ball lightning, right?
The Austrian scientists suggest that as many as 50 percent of reported sightings of ball lightning might be hallucinations -- magnetic stimulation of the brain and retina. But since other reports are coupled with non-visual stimuli like smells and sounds, or record floating orbs of orange, green or blue, it's likely that we can still consider ball lightning a legitimate, if mysterious, atmospheric phenomenon.