Ball lightning is an atmospheric phenomenon, the physical nature of which is still controversial. The term refers to reports of a luminous object which varies in size from golf ball to several meters in diameter. It is sometimes associated with thunderstorms, but unlike lightning flashes arcing between two points, which last a small fraction of a second, ball lightning reportedly lasts many seconds. There have been some reports of producing a similar phenomenon in the laboratory, but some question whether it is the same phenomenon.

Reports

There have been over 10,000 reported sightings of ball lightning.[1] A 1960 paper reported that 5% of the US population reported having witnessed ball lightning.[2] Another study analyzed reports of 10,000 cases.[3]

Ball lightning is photographed very rarely, and details of witness accounts can vary widely. Many of the properties observed in ball lightning accounts conflict with each other, and it is very possible that several different phenomena are being incorrectly grouped together. It is also possible that some photos are fakes.

The discharges reportedly appear during thunderstorms, sometimes issuing from a lightning flash, but large numbers of encounters reportedly occur during good weather with no storms within hundreds of miles.

A report from an area of central Africa having a very high incidence of lightning said that ball lightning used to appear from a certain hill just before the onset of the rainy season.[4] (The report also exhibits a reluctance to report such phenomena typical of many people).

Ball lightning reportedly tends to rotate or spin and can possess odd trajectories such as veering off at an angle or rocking from side to side like a leaf falling. Ball lightning can also move with or against the wind. Other motions include a tendency to float (or hover) in the air and take on a ball-like appearance. Its shape has been described as spherical, ovoid, teardrop, or rod-like with one dimension being much larger than the others. Many are red to yellow in colour, sometimes transparent, and some contain radial filaments or sparks. Other colours, such as blue or white occur as well.

Sometimes the discharge is described as being attracted to a certain object, and sometimes as moving randomly. After several seconds the discharge reportedly leaves, disperses, is absorbed into something, or, rarely, vanishes in an explosion. Some accounts have the balls passing freely through wood or glass or metal, while other accounts report circular holes in the wood or glass or metal. Some report explosions when the balls contact electrical wiring or the vaporisation of water when the balls enter water. Some accounts say the balls are lethal, killing on contact, while other accounts say the opposite.
A 19th century depiction of ball lightning
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A 19th century depiction of ball lightning

Nikola Tesla reportedly could consistently make ball lightning in his Colorado lab, with one account saying that he was able to temporarily contain the balls in wooden boxes.

Pilots in World War II described an unusual phenomenon for which ball lightning has been suggested as an explanation. The pilots saw small balls of light "escorting" bombers, flying alongside their wingtips. Pilots of the time referred to the phenomenon as "foo fighters," initially believing that the lights were from enemy planes. However, there are other theories as to the identity of the foo fighters.

Submariners in WWII gave the most frequent and consistent accounts of small ball lightning in the confined submarine atmosphere. There are repeated accounts of inadvertent production of floating explosive balls when the battery banks were switched in/out, especially if mis-switched or when the highly inductive electrical motors were mis-connected or disconnected. An attempt later to duplicate those balls with a surplus submarine battery resulted in several failures and an explosion. [3]

Volcanos and the atmosphere and earth around them have been known to produce ball lightning and other luminous effects, with or without electrical storms. These accounts vary greatly.

Other accounts place ball lightning as appearing over a kitchen stove or wandering down the aisle of an airliner.[5] One report described ball lightning following and engulfing a car, causing the electrical supply to overload and fail. In 1773, two clergy men recalled that they saw a ball of light drop down in their fireplace. Seconds later, it exploded. [citation needed]

Some researchers suggest that ball lightning has a more diverse range of properties than previously thought (e.g. Singer, 1971). Japanese investigators (e.g. Ofuruton et al) report that Japanese ball lightning can occur in fine weather and be unconnected with lightning. The diameter is said to be typically 20–30 cm but sometimes even larger up to a few meters. Ball lightning can split and recombine and can exhibit large mechanical energy like carving trenches (e.g. Fitzgerald 1978) and holes into the ground.

Until recently, ball lightning was sometimes regarded as nothing more than a myth, fantasy, or hoax.[1] Reports of the phenomenon were dismissed due to lack of physical evidence, and were often regarded the same way as UFO sightings.

Historical accounts

One of the earliest and most destructive occurrences was reported to have taken place during The Great Thunderstorm at Widecombe-in-the-Moor, Devon, in England, on October 21 1638. Four people died and around 60 were injured when what appeared to have been ball lightning struck a church.[citation needed]

A famous anecdote from 1753 depicts ball lightning as having violent potential. Professor Georg Richmann, of Saint Petersburg, Russia created a kite flying apparatus similar to that built by Benjamin Franklin a year earlier. He was attending a meeting of the Academy of Sciences, when he heard thunder. The Professor ran home with his engraver to capture the event for posterity. While the experiment was underway, ball lightning appeared, collided with Richmann's forehead and killed him, leaving a red spot. His shoes were blown open, parts of his clothes singed, the engraver knocked out; the doorframe of the room was split, and the door itself torn off its hinges.[6][7]

Tsar Nicholas II, the last Emperor of Russia, reported witnessing what he called "a fiery ball" while in the company of his grandfather, Tsar Alexander II: "Once my parents were away," recounted the Tsar, "and I was at the all-night vigil with my grandfather in the small church in Alexandria. During the service there was a powerful thunderstorm, streaks of lightning flashed one after the other, and it seemed as if the peals of thunder would shake even the church and the whole world to its foundations. Suddenly it became quite dark, a blast of wind from the open door blew out the flame of the candles which were lit in front of the iconostasis, there was a long clap of thunder, louder than before, and I suddenly saw a fiery ball flying from the window straight towards the head of the Emperor. The ball (it was of lightning) whirled around the floor, then passed the chandelier and flew out through the door into the park. My heart froze, I glanced at my grandfather - his face was completely calm. He crossed himself just as calmly as he had when the fiery ball had flown near us, and I felt that it was unseemly and not courageous to be frightened as I was....After the ball had passed through the whole church, and suddenly gone out through the door, I again looked at my grandfather. A faint smile was on his face, and he nodded his head at me. My panic disappeared, and from that time I had no more fear of storms." [4]

British occultist Aleister Crowley also reported witnessing what he referred to as "globular electricity" during a thunderstorm on Lake Pasquaney in New Hampshire in 1916. As related in his Confessions, he was sheltered in a small cottage when he "noticed, with what I can only describe as calm amazement, that a dazzling globe of electric fire, apparently between six and twelve inches in diameter, was stationary about six inches below and to the right of my right knee. As I looked at it, it exploded with a sharp report quite impossible to confuse with the continuous turmoil of the lightning, thunder and hail, or that of the lashed water and smashed wood which was creating a pandemonium outside the cottage. I felt a very slight shock in the middle of my right hand, which was closer to the globe than any other part of my body."[8]

On 30 April 1877, a ball of lightning entered the Golden Temple at Amritsar, India, and exited through a side door. This event was observed by a number of people, and the incident is inscribed on the front wall of Darshani Deodhi.[citation needed]

On August 6 1994 a ball of lightning went through a closed window in Uppsala, Sweden, leaving a circular hole with a diameter of 5 centimeters. The incident was witnessed by residents in the area, and was recorded by a lightning strike tracking system on the Division for Electricity and Lightning Research at Uppsala University.[9][10]

Homemade experiments

Many sources of information on ball lightning often make mention of a questionably related phenomenon commonly referred to as plasma balls. These floating balls of light often accompany a larger ball of fire that occurs when a lit or recently extinguished match or other material is immediately placed in an ordinary kitchen microwave on high power. These experiments are easily reproduced in home appliances and numerous websites exist with instructions on how to recreate it. Home video clips as well as video of public demonstrations of the occurrence have been posted.[11][12][13]

The experiments usually involve lighting a match and either microwaving it while lit or blowing out the match and then microwaving it immediately. The plasma balls are usually bright and bluish in color, and roll around at the ceiling of the microwave chamber. A buzzing sound is characteristically observed while the plasma balls are present.

The effect tends to damage the chamber where the plasma ball(s) have appeared, producing dents in the chamber wall or ceiling, as well as leaving burn marks. Some instructions for the experiment describe covering the lit object with an inverted glass jar, which would contain the flame and "plasma balls" so that they wouldn't damage the microwave oven itself.

Although this phenomenon has been referred to as ball lightning or plasma balls, these names are more a description of their appearance than they are based on scientific fact. It has not been proven that it is actually related to the natural occurrence of ball lightning, or that the balls are made of plasma. No truly scientific explanation currently exists for the phenomenon.

Analysis/theories

Currently there is no widely accepted explanation of what exactly ball lightning is, despite several theories that have been advanced since the phenomenon was brought into the scientific realm by the French Academy scientist François Arago.

An early attempt to explain ball lightning was recorded by Nikola Tesla in 1904.[14]

Difficult features of the lightning include its persistence and its near-neutral buoyancy in air. A popular hypothesis is that ball lightning is a highly ionized plasma contained by self-generated magnetic fields: a plasmoid.[citation needed] This hypothesis is not initially credible. If the gas is highly ionized, and if it is near thermodynamic equilibrium, then it must be very hot. Since it must be in pressure equilibrium with the surrounding air, it will be much lighter and hence float up rapidly. Magnetic fields, if present, might provide the plasmoid's coherence, but will not reduce this buoyancy. In addition, a hot plasma cannot persist for long because of recombination and heat conduction.

There may, however, be some novel form of plasma for which the above arguments do not fully apply. For example, a plasma may be composed of negative and positive ions, rather than electrons and positive ions. In that case, the recombination may be rather slow even at ambient temperature. One such theory involves positively charged hydrogen and negatively charged nitrites (NO2–) and nitrates (NO3–). In this theory, the role of the ions as seeds for the condensation of water droplets is important.[citation needed]

If ball lightning releases energy stored in chemical form, its persistence and neutral buoyancy might be more easily understood. The reaction might proceed slowly due to kinetic or geometric constraints, and the reaction could take place near ambient temperature. One of the first detailed theories of this sort involved the oxidation of nanoparticle networks formed when normal lightning strikes on soil.[15]

The coherence of the collection of nanoparticles may be enhanced by vortex motion, like that of a smoke ring.[16]

A proposed explanation[verification needed] for the numerous colours reported for ball lightning is the following known gas phase chemoluminescent reaction:

NO+O3 → NO2[◊]+ O2

Broadband visible light is emitted from the NO2 as it reverts to a lower energy state. This explanation is supported by the numerous witness accounts of the presence of ozone.

Currently, one prominent theory suggests that ball lightning is nothing more than burning vaporized silicon. When lightning strikes earth's silica-rich soil, the silicon could be instantly vaporized, the vapor itself condensing and burning slowly via the oxygen in the surrounding air. A recently published experimental investigation of this effect by evaporating pure silicon with an electric arc reported producing "luminous balls with lifetime in the order of seconds".[17][18][19] Videos of this experiment are available online.[20]

Another current theory published by Oleg Meshcheryakov suggests that ball lightning is made of composite nano or submicrometre particles, each particle constituting a nanobattery. A surface discharge shorts these batteries, resulting in a current which forms the ball. His model is described as an aerosol, but not aerogel, model that explains all the observable properties and processes of ball lightning.[21][22]

Singer in his monograph, The Nature of Ball Lightning, published by Plenum Press critiques several classes of theory. Most theory can match some of the reported properties of ball lightning but not all. In addition there are several difficulties that need to be overcome with many of the proposed theories.

Ball lightning theories are distinguished by having the energy either self-contained or with energy being supplied to the ball by an external source. In the latter case much longer life times are possible.

The types of theories vary widely. There are electrical discharge theories, spinning electric diplole theory, electro-static Leyden jar theories, nuclear theories, trapped microwave theories, fractal aerogel theories, magnetically-trapped plasma theories, vortex theories, metallic vapour theories, Rydberg matter theories, chemical combustion theories, black hole theories, antimatter theories, optical illusions (e.g. lightning after image on the retina theory etc).

Each of these theories is now described. These are the types of candidate theories but they need to be able to account for eyewitness accounts. No one theory has been widely accepted so there needs to be some debate within the scientific community as to the likely cause of ball lightning.

1. Spinning electric dipole theory. (Endean (1976) published this theory. He postulated that ball lightning could be described as an electric field vector spinning in the microwave frequency region.)
2. Electrostatic Leyden jar models. (Singer (1971) discusses this type of theory and suggested that the electrical recombination time would be too short for the ball lightning lifetimes often reported.)
3. Nuclear theories
4. Trapped microwave theories
5. Maser caviton theory
6. Fractal aerogel theories (Smirnov (1987) put forward a charged aerosol cluster theory.)
7. Magnetically trapped plasma theories
8. Vortex theories (Coleman (2006) described ball lightning as a vortex fireball or natural vortex burning a combustible fuel. Ball lightning under this theory is essentially a turbulent swirling flame inside a vortex.
9. Rydberg matter theories
10. Chemical combustion theories
11. Black hole theories
12. Anti-matter theories
13. Optical illusions.

Esoteric explanations

Ball lightning has been connected to reports of several supernatural phenomena, ranging from will o' the wisps to UFOs. Some people believe the ball lightning phenomena are ghosts or spirits, or are related to poltergeists and spontaneous human combustion.[1] References can be seen in the will o' the wisp and other spirits that take the guise of orbs of light. Some UFO skeptics have suggested that many apparent close encounters are actually observations of ball lightning. UFO enthusiasts report seeing ball lightning often at crop circle sites and believe them to be some kind of intelligence or come from some kind of intelligence while not denying that it is indeed ball lightning.

Another esoteric explanation that has been offered for ball lightning is that it is the passage of microscopic primordial black holes through the Earth's atmosphere. No such tiny black holes have ever been positively detected, and it is uncertain whether they would have the physical properties described by ball lightning if they did in fact exist and in great enough quantity to account for ball lightning reports. This explanation also would not account for their alleged co-occurrence with electrical storms. However, inspired by accounts of ball lightning that, amongst other physically verifiable effects, had ploughed a 90-metre trench across peat bogs in Ireland, Pace Vandevender, a plasma physicist who worked until his retirement on thermonuclear fusion at Sandia National Laboratories in Albuquerque, New Mexico, believes that no explanation other than a black hole with a mass of more than 20 tonnes could explain the displacement of more than 100 tonnes of peat. His colleagues at Sandia agreed that, crazy though the hypothesis seems, it was worthy of the attention of a national laboratory.[23]

Ball lightning in mythology and fiction

Among the ancients of Japanese mythology, there is a myth that ball lightning is the wrath of the thunder god, Raijin from Japanese mythology. In Basque mythology ball lightning were believed to be either main deity, Mari or Sugaar, travelling from one mountain to another. M. l'abbé de Tressan in, Mythology compared with history: or, the fables of the ancients elucidated from historical records,

...during a storm which endangered the ship Argo, fires were seen to play round the heads of the Tyndarides, and the instant after the storm ceased. From that time, those fires which frequently appear on the surface of the ocean were called the fire of Castor and Pollux. When two were seen at the same time, it announced the return of calm, when only one, it was the presage of a dreadful storm. This species of fire is frequently seen by sailors, and is a species of ignis fatuus. (page 417)

A ball lightning, as depicted on the front cover of The Seven Crystal Balls
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A ball lightning, as depicted on the front cover of The Seven Crystal Balls

Some phenomena known from folklore, such as the will o' the wisp, may be related to ball lightning.

An early fictional reference to ball lightning appears in a children's book set in the 1800s by Laura Ingalls Wilder.[24] The books are considered historical fiction, but the author always insisted they were descriptive of actual events in her life. In Wilder's description, three separate balls of lightning appear during a winter blizzard near a cast iron stove in the family's kitchen. They are described as appearing near the stovepipe, then rolling across the floor, only to disappear as the mother (Caroline Ingalls) chases them with a willow-branch broom.[25]

Ball lightning also occurs in The Seven Crystal Balls, one of the books in The Adventures of Tintin series. In Stephen King's novella The Body, the narrator and his friends encounter this phenomenon traveling down railroad tracks just outside the fictional town of Castle Rock. A ball lightning named Skip makes a brief appearance as a character in Thomas Pynchon's novel Against the Day.

Fantasy fiction and games feature ball lightning as an attack spell cast by mage characters.[citation needed]