Ball lightning is usually reported to occur during thunderstorms, most often associated with a real lightning discharge. However, many of the reports have it appearing during fine weather with no storms around. This raises many possibilities, such as: there is more than one kind, or they are different phenomena, or people are mistaken or lying.
Ball lightning floats or hovers. It can appear to be attracted to an object or person, or to move randomly. After a few seconds it moves away or is absorbed by something or quietly disperses or, rarely, audibly explodes.
In appearance it can have different shapes and colors. It can be spherical, from the size of a golf ball to a basketball usually, although there are reports of rare lightning balls large enough to engulf a car. It can be rod-shaped, teardrop-shaped or egg-shaped. It can be yellow or red, blue or white, even transparent with sparks or spokes inside.
It has been seen to roll or bounce across the ground, and even down the aisle of a passenger airplane. It can divide and recombine. A very energetic one might gouge a groove in the ground.
If ball lightning is a plasma it has to be an unusual type of plasma that is close to the ambient air temperature. It’s more likely to be a chemical reaction between the air and a cloud of tiny mineral particles. The energy would be dissipated as heat and light as the minerals oxidize, or burn. Alternatively, if nitric oxide combines with ozone to produce nitrogen dioxide and oxygen, it will release visible light, much as a neon light does.
One plausible explanation for at least some sightings is that it’s an optical illusion caused by a bright flash of lightning, similar to the spot in one’s vision caused by a photographer’s flash.
A look at ball lightning wouldn’t be complete without some of the more imaginative explanations. These include will o’ the wisps, UFOs, sprites and fairies, ghosts and poltergeists. One hypothesis involves microscopic black holes.
Ball lightning also appears in mythology and other literature. It can be an artifact of the wrath of a god, or it can be the god, depending on the myth. It can be a sign from a god portending good or ill, depending. It has appeared in the Adventures of Tin Tin by author Georges Remi, as well as the books of many other authors.
Ball lightning is half fact and half fantasy.