This form of lightning is unexplainable, unpredictable, and rare.
Ball lightning is one of those phenomena that is more or less universally understood to be amazing when experienced anecdotally but potentially terrifying when experienced firsthand. These glowing, often grapefruit-sized orbs of blue, electric light seem to form spontaneously, sometimes inside people’s homes or around airplanes generally only last for a few seconds and aren’t well understood. It’s nearly impossible to empirically study them or create them because there is no broadly accepted explanation for how they originate.
Recorded sightings of these hovering, glowing spheres, which can range in size from a penny to several yards across, date back to ancient Greece.
One of the first recorded sightings of ball lightning occurred in 1638, when a “great ball of fire” came through the window of an English church. That and other early accounts suggest that ball lightning can be deadly.
At least one study has theorized that about half of all ball lightning sightings are hallucinations caused by the magnetic fields during storms. Scientists seem to agree ball lightning is real, even if they don’t yet fully understand what causes it. Until recently many people didn’t even think they were real.The most plausible idea to explain ball lightning is vaporized silicon. In this hypothesis, a bolt of lightning strikes a spot of silica-rich soil, sending an orb of charged particles airborne. The inherent electricity causes the orb to glow.
Until recently, ball lightning was often regarded as a fantasy or a hoax. Reports of the phenomenon were dismissed for lack of physical evidence, and were often regarded the same way as UFO sightings.
The presence of glass may generate ball lightning, according to another theory. Atmospheric ions could pile up at the surface of a window, producing enough of an electrical field on the other side to generate a discharge. Another study, suggests that microwave radiation produced when lightning strikes the ground could become encapsulated in a plasma bubble, resulting in ball lightning.
Ball lightning has also been associated with earthquakes. The rare flashes of light sometimes seen around earthquakes can take many forms: bluish flames that appear to come out of the ground at ankle height; quick flashes of bright light that resemble regular lightning strikes, except they originate from the ground instead of the sky; and the floating orbs known as ball lightning. In a 2014 study of earthquake lights, researchers concluded that certain rocks tend to release electrical charges when a seismic wave hits, sparking colorful displays of light.
Despite all these investigations and lab experiments, ball lightning still refuses to be pinned down. Scientists say they have much to learn about the mysterious phenomenon.