Scientists still can’t fully explain the glowing spheres called ball lightning

Witnesses across centuries have described the same strange sight during violent thunderstorms: a glowing sphere, sometimes the size of a pea and sometimes several meters across, drifting silently through the air or rolling along the ground before vanishing or bursting apart. Reports place the glowing orbs indoors, on ships, near power lines and inside aircraft, often with no clear connection to the lightning bolt that struck moments earlier.

Despite generations of investigation, the phenomenon has never been reliably reproduced or measured in a controlled setting, leaving it as one of the few well-documented weather events that modern physics still cannot fully account for.

A Phenomenon Defined by What It Is Not

Ball lightning is distinct from a standard lightning bolt, which lasts a fraction of a second as electricity discharges along a jagged channel between cloud and ground. Witnesses instead describe luminous spheres that persist for several seconds, occasionally longer, moving at walking pace or hovering in place before disappearing. It is also distinguished from other glowing atmospheric effects such as St. Elmo’s fire, a corona discharge that clings to pointed objects like ship masts, and the marsh gas ignitions sometimes blamed for will-o’-the-wisp sightings, according to the summary maintained on Wikipedia.

Centuries of Eyewitness Reports

Accounts of the phenomenon stretch back hundreds of years, collected from sailors, farmers, pilots and, in the 20th century, meteorologists caught in storms with no equipment ready to record what they saw. One of the earliest widely cited accounts describes a glowing ball entering a church in Devon, England, during a thunderstorm in 1638, an event contemporaries described in terms strikingly similar to reports gathered centuries later. Descriptions vary widely in color, from pale blue to orange to yellow, and in behavior, with some reports describing spheres that pass through closed windows or walls without leaving visible damage, and others describing an explosion at the end of the sighting accompanied by a smell resembling sulfur or ozone. The inconsistency across reports has made ball lightning difficult to classify as a single physical event rather than several unrelated phenomena that happen to look similar. Survey-based estimates suggest a surprisingly large share of the population reports having witnessed something matching the description at some point, though the figures vary widely depending on how a survey defines the phenomenon and how it screens out other bright, brief lights such as ball-shaped afterimages, St. Elmo’s fire or meteor fireballs. That gap between a commonly reported experience and a scientifically confirmed cause has kept ball lightning research active across multiple countries for more than a century, spanning independent investigations in the United States, Russia, China and several European nations rather than any single national research program.

Why the Physics Remains Unsettled

The central puzzle for researchers is energy. A standard lightning flash releases its energy almost instantly, but a glowing sphere that persists for multiple seconds needs some mechanism to store or continuously generate energy after the initial strike has ended. Proposed explanations include a lightning strike vaporizing silicon compounds in soil, producing a cloud of fine particles that oxidize in air and glow as they burn; plasma held together briefly by its own electromagnetic field; and microwave energy trapped inside a bubble of ionized air. Each theory can reproduce some features of reported sightings in laboratory tests, but none has been confirmed as the actual mechanism behind naturally occurring events.

The Trouble With Studying a Phenomenon on Nobody’s Schedule

Ball lightning’s rarity and unpredictability have made it one of the hardest atmospheric events to study directly. Meteorological instruments are built to capture storms broadly, not to isolate a fast, localized event that might last only a few seconds in one specific spot. Photographic and video evidence exists, including footage captured in China during a 2012 field campaign that recorded a spectral signature consistent with vaporized soil elements, but such direct measurements remain exceedingly rare. Most of what scientists know still comes from eyewitness testimony collected after the fact, which is useful for identifying patterns but difficult to verify against a physical model.

Laboratory Attempts to Recreate the Effect

Physicists have managed to generate glowing, floating plasma balls in laboratory settings using microwave generators, electrical discharges through water, and other controlled methods, and some of these lab-made spheres bear a visual resemblance to eyewitness descriptions. Researchers are careful to note the limits of that resemblance, however, since a laboratory plasma ball produced under tightly controlled conditions does not necessarily behave the same way, or arise from the same cause, as whatever generates the effect during an actual thunderstorm. The gap between reproducing an appearance and confirming a mechanism is part of why the scientific literature on the subject remains open rather than settled.

An Open Question in a Field Built on Prediction

Modern meteorology can forecast storm tracks, model lightning strike probability and issue warnings hours in advance, which makes ball lightning something of an outlier: a documented weather-adjacent phenomenon that resists the same predictive tools applied successfully almost everywhere else in atmospheric science. Researchers continue to collect eyewitness reports, test competing models, and watch for the rare instance when instruments happen to be pointed the right way at the right moment, in hopes of eventually closing the gap between what people have reported seeing for centuries and what physics can currently explain.

This article was produced with the assistance of AI and reviewed by an editor.

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