Ball Lightning

Ball lightning is an unexplained atmospheric electrical phenomenon. The term refers to reports of luminous, spherical objects that vary from pea-sized to several meters in diameter. Though usually associated with thunderstorms, the phenomenon lasts considerably longer than the split-second flash of a lightning bolt. Many early reports claim that the ball eventually explodes, sometimes with fatal consequences, leaving behind the odor of sulfur.

Until the 1960s, most scientists argued that ball lightning was not a real phenomenon but an urban myth, despite numerous reports from throughout the world. Laboratory experiments can produce effects that are visually similar to reports of ball lightning, but how these relate to the natural phenomenon remains unclear. Scientists have proposed many hypotheses about ball lightning over the centuries. Scientific data on natural ball lightning are scarce, owing to its infrequency and unpredictability. The presumption of its existence depends on reported public sightings, and has therefore produced somewhat inconsistent findings. Owing to inconsistencies and to the lack of reliable data, the true nature of ball lightning remains unknown. The first ever optical spectrum of what appears to have been a ball-lightning event was published in January 2014 and included a video at high frame-rate.

Direct measurements of natural ball lightning

In January 2014, scientists from Northwest Normal University in Lanzhou, China, published the results of recordings made in July 2012 of the optical spectrum of what was thought to be natural ball lightning made by chance during the study of ordinary cloud–ground lightning on the Tibetan Plateau.

At a distance of 900 m (3,000 ft), a total of 1.64 seconds of digital video of the ball lightning and its spectrum was made, from the formation of the ball lightning after the ordinary lightning struck the ground, up to the optical decay of the phenomenon. Additional video was recorded by a high-speed (3000 frames/sec) camera, which captured only the last 0.78 seconds of the event, due to its limited recording capacity. Both cameras were equipped with slitless spectrographs.

The researchers detected emission lines of neutral atomic silicon, calcium, iron, nitrogen and oxygen - in contrast with mainly ionized nitrogen emission lines in the spectrum of the parent lightning. The ball lightning traveled horizontally across the video frame at an average speed equivalent of 8.6 m/s (28 ft/s). It had a diameter of 5 m (16 ft) and covered a distance of about 15 m (49 ft) within those 1.64 s.

Oscillations in the light intensity and in the oxygen and nitrogen emission at a frequency of 100 hertz, possibly caused by the electromagnetic field of the 50 Hz high-voltage power transmission line in the vicinity, were observed. From the spectrum, the temperature of the ball lightning was assessed as being lower than the temperature of the parent lightning (<15,000–30,000 K (14,700–29,700 °C; 26,500–53,500 °F)). The observed data are consistent with vaporization of soil as well as with ball lightning's sensitivity to electric fields.

Historical Accounts

It has been suggested that ball lightning could be the source of the legends that describe luminous balls, such as the mythological Anchimayen from Argentinean and Chilean Mapuche culture. In a 1960 study, 5% of the population of the Earth reported having witnessed ball lightning. Another study analyzed reports of 10,000 cases. Read more ...

Ball Lightning In the News ...

A New Explanation for One of the Strangest Occurrences in Nature: Ball Lightning - July 24, 2016

Some fireballs appear to be the products of living organisms. The decay of organic matter, for example, in marshes and other wetlands (or even a mass grave in a Polish forest) leads to the release of methane and phosphorus-containing gases such as phosphine, which can spontaneously catch fire after encountering oxygen in the atmosphere, producing a flickering light suspended midair. Some, on the other hand, are electrical in origin, sparking within the ground during an earthquake as stressed rocks release a stream of electrons to the surface where, interacting with air, they produce flashes of light. Still others form in the atmosphere, usually during thunderstorms, and go by the name of ball lightning.

  Natural Ball Lightning Recorded By Scientists For First Time Eve   Huffington Post - January 25, 2014

Great balls of lightning! Bizarre glow that has eluded scientists for centuries is captured on video for the first time   Daily Mail - January 20, 2014

Green fireball UFOs identified   NBC - December 1, 2010

Green fireballs that streaked across the sky and rolled down an Australian mountainside four years ago, spurring reports of UFOs in the area, might have been meteors and ball lightning, a researcher suggests. At least three traffic-light green fireballs brighter than the moon but not as bright as the sun blazed over northeast Australia on May 16, 2006. A farmer saw one with a blue tapering tail pass over the mountains of the Great Divide about 75 miles (120 kilometers) west of Brisbane, then watched a phosphorescent green ball about 12 inches wide (30 centimeters wide) roll slowly down the side of a mountain, bouncing over a rock along the way. Green fireballs have been seen many times in the sky, and are typically explained as meteors whose shockwaves lead to electrically charged oxygen similar to that seen in auroras. In fact, a commercial airline pilot who landed in New Zealand that day reported seeing a meteor breaking up into fragments, which turned green as the bits descended in the direction of Australia.

Mysterious Ball Lightning: Illusion or Reality?   Science Daily - May 20, 2010
Ball lightning is a rare circular light phenomenon occurring during thunderstorms. Scientists have been puzzled by the nature of these apparent fire balls for a long time. Now physicists have calculated that the magnetic field of long lightning strokes may produce the image of luminous shapes, also known as phosphenes, in the brain. This finding may offer an explanation for many ball lightning observations.

Using fireballs to uncover the mysteries of ball lightning PhysOrg - February 18, 2008
Now, working with fellow Rennes scientist LeGarrec, as well as Dikhtyar and Jerby from Tel Aviv University and Sztucki and Narayanan at the European Synchrotron Radiation Facility in Grenoble, France, Mitchell can prove that nanoparticles likely exist in ball lightning. The results of the work by Mitchell and his colleagues can be found in Physical Review Letters: Evidence for Nanoparticles in Microwave-Generated Fireballs Observed by Synchrotron X-Ray Scattering. Right now, it looks as though one of the mysteries of ball lightning has been solved. This experiment has provided a strong case for the presence of nanoparticles in ball lightning. The next step is discovering what scientists can do with the information.

Ball Lightning: A Shocking Scientific Mystery National Geographic - June 2, 2006

People have reported seeing ball lightning a rare phenomenon that resembles a glowing sphere of electricity for hundreds of years. But scientists still can't explain what causes it, or even exactly what it is. Ball lightning floats near the ground, sometimes bounces off the ground or other objects, and does not obey the whims of wind or the laws of gravity. An average ball lightning glows with the power of a 100-watt bulb. Some have been reported to melt through glass windows and burn through screens. The record suggests that ball lightning is not inherently deadly, but there are reports of people being killed by contact most notably the pioneering electricity researcher Georg Richmann, who died in 1753. Richmann is believed to have been electrocuted by ball lightning as he conducted a lightning-rod experiment in St. Petersburg, Russia. The phenomenon lasts only a short time, perhaps ten seconds, before either fading away or violently dissipating with a small explosion.

Lightning, Sprites, Elves