|
|
|
|
Ball lightning
|
| |
|
| |
Ball lightning may be an atmospheric electrical phenomenon, the physical nature of which is still controversial. The term refers to reports of luminous, usually spherical objects which vary from pea-sized to several meters in diameter. It is sometimes associated with thunderstorms, but unlike lightning flashes, which last only a fraction of a second, ball lightning reportedly lasts many seconds.
Laboratory experiments have produced effects that are visually similar to reports of ball lightning, but it is presently unknown whether these are actually related to any naturally occurring phenomenon.
Discussion
Ask a question about 'Ball lightning' Start a new discussion about 'Ball lightning' Answer questions from other users |
Encyclopedia
Ball lightning may be an atmospheric electrical phenomenon, the physical nature of which is still controversial. The term refers to reports of luminous, usually spherical objects which vary from pea-sized to several meters in diameter. It is sometimes associated with thunderstorms, but unlike lightning flashes, which last only a fraction of a second, ball lightning reportedly lasts many seconds.
Laboratory experiments have produced effects that are visually similar to reports of ball lightning, but it is presently unknown whether these are actually related to any naturally occurring phenomenon. Scientific data on natural ball lightning is scarce owing to its infrequency and unpredictability. The presumption of its existence is based on reported public sightings, and has therefore produced somewhat inconsistent findings. Given inconsistencies and the lack of reliable data, the true nature of ball lightning is still unknown. 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.
Natural ball lightning appears infrequently and unpredictably, and is therefore rarely (if ever truly) photographed. However, several purported photos and videos exist. Perhaps the most famous story of ball lightning unfolded when 18th-century physicist Georg Wilhelm Richmann installed a lightning rod in his home and was struck in the head - and killed - by a "pale blue ball of fire."
Historical accounts
A 1960 paper reported that 5% of the US population reported having witnessed ball lightning. Another study analyzed reports of 10,000 cases.
The Great Thunderstorm
One of the earliest and most destructive occurrences was reported during The Great Thunderstorm at a church in Widecombe-in-the-Moor, Devon, in England, on 21 October 1638. Four people died and approximately 60 were injured when, during a severe storm, an 8' ball of fire struck and entered the church, nearly destroying it. Large stones from the church walls were hurled into the ground and through large wooden beams. The ball of fire smashed the pews and many windows, and filled the church with a foul sulfurous odor and dark, thick smoke.
The ball of fire reportedly split in two, one exiting through a window by smashing it open, the other disappearing somewhere inside the church. The explanation at the time, because of the fire and sulfur smell, was that the ball of fire was "the devil" or the "flames of hell". Later, some blamed the entire incident on two people who had been playing cards in the pew during the sermon, who they say must have invoked God's wrath.
Georg Richmann
A report from 1753 depicts ball lightning as being lethal, when Professor Georg Richmann of Saint Petersburg, Russia, created a kite flying apparatus similar to the one proposed by Benjamin Franklin a year earlier. He was attending a meeting of the Academy of Sciences when he heard thunder, and 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.
The ball left a red spot on Richmann's forehead, his shoes were blown open, and parts of his clothes singed. His engraver was knocked unconscious. The doorframe of the room was split, and the door itself torn from its hinges.
Tsar Nicholas II
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."
Aleister Crowley
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."
Other accounts
- 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.
- In July 1907 the Cape Naturaliste Lighthouse in Western Australia was hit by ball lightning. The light house keeper Patrick Baird was in the tower at the time and was knocked unconscious. His daughter Ethel recorded the event
- 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 moving in strange trajectories, which came to be referred to as 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.
- On 6 August 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.
Inconsistent characteristics
Depending on the report, ball lightning can move upwards as well as downwards, sideways, or in odd trajectories such as rocking from side to side like a falling leaf. It can move with or against the wind, or simply hover, more or less stationary in the air. Sometimes it is described as being attracted to houses, cars, persons, or other objects, but sometimes the balls are reportedly repelled or are unaffected by objects. Some accounts claim the balls have passed freely through solid masses, such as wood or metal, without any effect on the ball or material, while other accounts report damage to the material, such as melting or burning. Some reports suggest an attraction to, or even an origination from electric power lines.
Ball lightning has been reported in many different colors, sometimes even transparent or translucent. It is sometimes said to contain radial filaments or sparks while others are evenly lit, and some have flames protruding from the ball surface. Its shape has been described as spherical, oval, tear-drop, rod-like, and sometimes, but rarely, even disk-like.
It has sometimes been reported during thunderstorms, sometimes issuing from a lightning flash, while sometimes it appears during calm weather with no storms in the vicinity.
The balls have been reported to disperse in many different ways, such as suddenly vanishing, gradually dissipating, absorption into an object, "popping," exploding loudly, or even exploding with force, which is sometimes reported as damaging. Some accounts say the balls are lethal, killing on contact, while other accounts claim that they are harmless.
Laboratory experiments
Scientists have long attempted to produce ball lightning in laboratory experiments. While some experiments have produced effects that are visually similar to reports of natural ball lightning, it has not yet been determined whether there is actually any correlation.
Nikola Tesla reportedly was able to artificially produce ~1.5" balls, but he was really interested in higher voltages and powers, and remote transmission of power, so the balls he made were just a curiosity.
There is a scientific group that holds a regular symposium on ball lightning, called the "International Symposium on Ball Lightning" or ISBL: , , . The most recent symposium took place in Kaliningrad, Russia in 2008. A related group uses the generic name "Unconventional Plasmas".
Water discharge experiments
Some scientific groups, including the Max Planck Institute, have reportedly produced a ball lightning-type effect by discharging a high-voltage capacitor in a tank of water.
Home microwave oven experiments
Many modern experiments involve using a microwave oven to produce small rising glowing balls, often referred to as "plasma balls".
Generally, the experiments are conducted by placing a lit or recently extinguished match or other small object in an ordinary microwave oven. The burnt portion of the object flares up into a large ball of fire, while the "plasma balls" can be seen floating around the ceiling of the oven chamber. The effect is caused by electricity arcing between the conductive carbon particles in the soot, similar to the way electricity arcs between the tines of a fork. This can damage the oven by leaving burn marks and causing high voltage electrical discharge back into the magnetron.
Some experiments describe covering the lit object with an inverted glass jar, which contains both the flame and the balls so that they will not damage the chamber walls. Other experimenters report that substituting a nickel for the match grants the best results. Some experimenters have posted instructions, photos, and videos of these experiments.
Silicon experiments
Some more recent experiments in 2007 involve shocking silicon wafers with electricity, which vaporizes the silicon and induces oxidation in the vapors. The visual effect can be described as small glowing, sparkling orbs that roll around a surface. Two Brazilian scientists, Antonio Pavão and Gerson Paiva of the Federal University of Pernambuco have reportedly consistently made small long-lasting balls using this method. These experiments stemmed from the theory that ball lightning is actually oxidized silicon vapors (see vaporized silicon hypothesis, below).
Possible scientific explanations
An early attempt to explain ball lightning was recorded by Nikola Tesla in 1904, but currently, there is no widely accepted explanation of what exactly ball lightning is. Several theories have been advanced, however, since the phenomenon was brought into the scientific realm by the French Academy scientist François Arago.
Vaporized silicon hypothesis
This hypothesis suggests that ball lightning consists of vaporized silicon burning through oxidation. When lightning strikes earth's silica-rich soil, the silicon could be instantly vaporized, the vapor itself condensing and burning slowly in 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". Videos of this experiment have been made available.
Nanobattery hypothesis
Another current hypothesis published by Oleg Meshcheryakov suggests that ball lightning is made of composite nano or submicrometre particles, each particle constituting a battery. 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.
Black hole hypothesis
Yet another hypothesis is that some extreme ball lightning is actually the passage of microscopic primordial black holes through the Earth's atmosphere as proposed by Mario Rabinowitz in Astrophysics and Space Science journal in 1999, http://arxiv.org/abs/astro-ph/021225; and earlier. Inspired by M. Fitzgerald’s account of ball lightning on August 6, 1868, in Ireland that lasted 20 minutes and left a 6 meter square hole, a 90 meter long trench, a second trench 25 meters long, and a small cave in the peat bog, Pace VanDevender, a plasma physicist at Sandia National Laboratories in Albuquerque, New Mexico, and his team found depressions consistent with Fitzgerald’s report and inferred that the evidence is inconsistent with thermal (chemical or nuclear) and electrostatic effects. An electromagnetically levitated, compact mass of >20,000 kg would produce the reported effects but requires a density of > 2000 times the density of gold, which implies a miniature black hole. He and his team found a second event in the peat-bog witness plate from 1982 and are currently trying to geolocate electromagnetic emission consistent with the hypothesis. His colleagues at the institute agreed that, crazy though the hypothesis seemed, it was worthy of their attention.
Other hypotheses
There also are many other hypotheses put forth to explain ball lightning, such as:
- Spinning electric dipole hypothesis. (Endean (1976) published this hypothesis. He postulated that ball lightning could be described as an electric field vector spinning in the microwave frequency region.)
- Electrostatic Leyden jar models. (Singer (1971) discusses this type of hypothesis and suggested that the electrical recombination time would be too short for the ball lightning lifetimes often reported.)
- J. Pace VanDevender separates extreme ball lightning of the highly energetic violent kind, and proposes a theory of neutrinos and heavy neutrinos.
- Nuclear hypotheses
- Trapped microwave hypotheses
- Maser hypothesis
- Fractal aerogel hypotheses (Smirnov (1987) put forward a charged aerosol cluster theory.)
- Magnetically trapped plasma theories
- Vortex hypotheses (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.
- Atmospheric Rydberg matter hypotheses
- Anti-matter hypotheses
- Optical illusions.
- Hallucinations associated with epileptic seizures. In a peer reviewed publication Cooray and Cooray (2008) show that the features of hallucinations experienced by patients having seizures in the occipital lobe are remarkably similar to the observed features of ball lightning. The study also shows that the rapidly changing magnetic field of a close lightning flash has a strength which is large enough to excite the neurons in the brain strengthening the possibility of lightning induced seizure in the occipital lobe of a person located close to a lightning strike establishing the connection between epileptic hallucination mimicking ball lightning and thunderstorms. The authors suggest that some of the reported ball lightning observations are probably hallucinations experienced during the epileptic seizures in the occipital lobe.
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. 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.
In popular culture
Mythology
- Among the ancients of Japanese mythology, there is a myth that ball lightning is the wrath of the thunder god, Raijin. Another shinto explanation is an apparition of the thunder being Raiju.
- 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)
- In Guyanese Mythology, there is a myth that the ole higue, the Guyanese form of a human vampire, capable of discarding her skin takes the form of an old woman living in a community. At night she transforms herself into a ball of fire, flies from her own house up into the sky and then lands on the roof of another house where there is a baby in a cradle underneath a sheet whose blood she will suck dry and then go home.
Literature
- An early fictional reference to ball lightning appears in a children's book set in the 19th century by Laura Ingalls Wilder. 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.
- In Pynchon's Against the Day, Merle Rideout, a photographer and lightning-rod salesman, befriends Skip, a telepathically communicative manifestation of ball lightning.
Film
- In the Russian film Burnt by the Sun a crackling lightning ball appears at several key moments throughout the picture. It passes through rooms, sometimes causing damage, like cracking the glass covering family photographs at the end of the feature. At one point, it explodes in the forest, setting a tree on fire.
See also
Further reading
- Coleman, P.F. 2006, J.Sci.Expl., Vol. 20, No.2, 215–238.
- Cooray, G. and V. Cooray, 2008, "Could some ball lightning observations be optical hallucinations caused by epileptic seizures, The open access atmospheric science journal, vol. 2, 101 – 105.
- Endean, V.G.,1976, Nature, 263,753,754.**Smirnov, 1987, Physics Reports, (Review Section of Physical Letters,152, No. 4, 177–226.*
External links
- *
- and — Various articles, experiments, and information on Ball lightning
- — the secret of ball lightning and a new field of science and technology*
- — Alternative "toaster" Microwave Experiments***
- VIDEO from YouTube (rare footages)
|
| |
|
|
