Lightning over Oradea in Romania

Lightning over Zwickau in Germany

Lightning over Ryman town. Northern Poland.

Lightning is an atmospheric discharge of electricity, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms.^[1] The leader of a bolt of lightning can travel at speeds of 60,000 m/s, and can reach temperatures approaching 30,000 °C (54,000 °F), hot enough to fuse soil or sand into glass channels.^[2][3] There are over 16 million lightning storms every year.^[1] Not to be confused with lightning. ... Lightning is a highly visible form of energy transfer. ... Lightning Lightning may refer to the following: in meteorology, lightning, the natural electrical phenomenon in slang, white lightning (a. ... Image File history File linksMetadata Download high resolution version (2048x3072, 3589 KB) This is a rotated version of Lightning over Oradea Romania. ... Image File history File linksMetadata Download high resolution version (2048x3072, 3589 KB) This is a rotated version of Lightning over Oradea Romania. ... Location of Oradea Coordinates: , Country County Status County capital Government  - Mayor Petru Filip (Democratic Party) Area  - County capital 111. ... Image File history File links Download high resolution version (2000x1130, 286 KB) Cloud to cloud lightning This image shows a cloud to cloud lightning in a very stormy and rainy night. ... Image File history File links Download high resolution version (2000x1130, 286 KB) Cloud to cloud lightning This image shows a cloud to cloud lightning in a very stormy and rainy night. ... Zwickau is a city of Germany, in the Bundesland Saxony (Sachsen), situated in a valley at the foot of the Erzgebirge, on the left bank of the Zwickauer Mulde, 130 km (82 miles) southwest of Dresden, south of Leipzig and south west of Chemnitz. ... Air redirects here. ... Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... A shelf cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... “Sandstorm” redirects here. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... For other uses, see Temperature (disambiguation). ... For other uses, see Celsius (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ... fulgurite Fulgurites (from the Latin fulgur meaning thunderbolt) are natural hollow carrot-shaped glass tubes formed in quartzose sand or soil by lightning strikes. ... A shelf cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ...

Lightning can also occur within the ash clouds from volcanic eruptions, or can be caused by violent forest fires which generate sufficient dust to create a static charge.^[1][4] Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... For other uses, see Wildfire (disambiguation). ... This box:      Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ...

How lightning initially forms is still a matter of debate:^[5] Scientists have studied root causes ranging from atmospheric perturbations (wind, humidity, and atmospheric pressure) to the impact of solar wind and accumulation of charged solar particles.^[6] Ice inside a cloud is thought to be a key element in lightning development, and may cause a forcible separation of positive and negative charges within the cloud, thus assisting in the formation of lightning.^[6] For other uses, see Wind (disambiguation). ... The term humidity is usually taken in daily language to refer to relative humidity. ... Atmospheric pressure is the pressure at any given point in the Earths atmosphere. ... The plasma in the solar wind meeting the heliopause The solar wind is a stream of charged particles (i. ... This article is about water ice. ... Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. ...

Early ideas and research about lightning

In the Christian faith, God is believed to be in command of the natural phenomena of lightning and thunderbolts. In the Book of Job God asks will lightning flash at your command? (Psalm 97:4 states, "His (God) lightnings light the world; The earth sees and trembles." Job 38:35). In his Dream Pool Essays written in AD 1088, the Song Dynasty polymath Chinese scientist Shen Kuo (1031-1095) wrote that when a house belonging to one Li Shunju had been struck by lightning, everyone assumed that the house would be burnt to the ground. To everyone's surprise, some of the wooden walls were merely blackened and lacquerwares untouched, while metal objects such as a steel sword were melted into liquid.^[7] Shen compared this phenomenon to the equally strange effects of water being unable to douse Greek fire (which had been known to the Chinese since the Arabs had traded it, or a chemical composition fairly equal to it, in the 10th century).^[7][8] For these strange effects of lightning, Shen wrote: The Book of Job (איוב) is one of the books of the Hebrew Bible. ... Shen Kuo (沈括) (1031-1095 AD) The Dream Pool Essays (Pinyin: Meng Xi Bi Tan; Wade-Giles: Meng Chi Pi Tan Chinese: 梦溪笔谈) was an extensive book written by the polymath Chinese scientist and statesman Shen Kuo (1031-1095) by 1088 AD, during the Song Dynasty (960-1279) of China. ... Northern Song in 1111 AD Capital Bianjing (汴京) (960–1127) Linan (臨安) (1127–1276) Language(s) Chinese Religion Buddhism, Taoism, Confucianism Government Monarchy Emperor  - 960–976 Emperor Taizu  - 1126–1127 Emperor Qinzong  - 1127–1162 Emperor Gaozong  - 1278–1279 Emperor Bing History  - Zhao Kuangyin taking over the throne of the Later Zhou... This is a Chinese name; the family name is Shen Shen Kuo or Shen Kua (Chinese: ; pinyin: ) (1031–1095) was a polymathic Chinese scientist and statesman of the Song Dynasty (960–1279). ... In a general sense, lacquer is a paint or varnish that produces a hard, durable finish that can be polished to a very high gloss, and gives the illusion of depth. ... For other uses, see Steel (disambiguation). ... Swiss longsword, 15th or 16th century Look up Sword in Wiktionary, the free dictionary. ... Greek fire was a burning-liquid weapon used by the Byzantine Greeks, typically in naval battles to great effect as it could continue burning even on water. ... For other uses, see Arab (disambiguation). ...

Thus was the frustration of learned men in his time of the desire to know the nature of lightning and other such common weather phenomena. However, in the Western world details of its force would become known by the 18th century. Occident redirects here. ...

Lightning strikes the Eiffel Tower in 1902.

Benjamin Franklin (1706-1790) endeavored to test the theory that sparks shared some similarity with lightning using a spire which was being erected in Philadelphia. While waiting for completion of the spire, he got the idea of instead using a flying object, such as a kite. During the next thunderstorm, which was in June 1752, it was reported that he raised a kite, accompanied by his son as an assistant. On his end of the string he attached a key, and he tied it to a post with a silk thread. As time passed, Franklin noticed the loose fibers on the string stretching out; he then brought his hand close to the key and a spark jumped the gap. The rain which had fallen during the storm had soaked the line and made it conductive. Image File history File links Metadata Size of this preview: 390 × 600 pixelsFull resolution (1030 × 1584 pixel, file size: 1. ... Image File history File links Metadata Size of this preview: 390 × 600 pixelsFull resolution (1030 × 1584 pixel, file size: 1. ... The Eiffel Tower (French: , ) is an iron tower built on the Champ de Mars beside the Seine River in Paris. ... Benjamin Franklin (January 17 [O.S. January 6] 1706 – April 17, 1790) was one of the most well known Founding Fathers of the United States. ... For other uses, see Philadelphia (disambiguation) and Philly. ... Yokaichi Giant Kite Festival held on the fourth Sunday every May in Higashiomi, Shiga, Japan Kite flying is the activity of flying tethered man-made objects in wind. ... A shelf cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... For other uses of this word, see Silk (disambiguation). ...

Franklin was not the first to perform the kite experiment. Thomas-François Dalibard and De Lors conducted it at Marly-la-Ville in France a few weeks before Franklin's experiment.^[9][10] In his autobiography (written 1771-1788, first published 1790), Franklin clearly states that he performed this experiment after those in France, which occurred weeks before his own experiment, without his prior knowledge as of 1752.^[11] In 1750 the US scientist Benjamin Franklin published a proposal for an experiment to determine if lightning was electricity. ...

As news of the experiment and its particulars spread, people attempted to replicate it. However, experiments involving lightning are always risky and frequently fatal. The most well-known death during the spate of Franklin imitators was that of Professor George Richmann of Saint Petersburg, Russia. He created a set-up similar to Franklin's, and was attending a meeting of the Academy of Sciences when he heard thunder. He ran home with his engraver to capture the event for posterity. According to reports, while the experiment was under way, ball lightning appeared, collided with Richmann's head, killing him and leaving a red spot.^[12][13] Richmann and his engrarver during the electrocution in St. ... Saint Petersburg (Russian: Санкт-Петербу́рг, English transliteration: Sankt-Peterburg), colloquially known as Питер (transliterated Piter), formerly known as Leningrad (Ленингра́д, 1924–1991) and Petrograd (Петрогра́д, 1914–1924), is a city located in Northwestern Russia on the delta of the river Neva at the east end of the Gulf of Finland... For other uses, see Thunder (disambiguation). ... For other uses, see Ball lightning (disambiguation). ...

Although experiments from the time of Franklin showed that lightning was a discharge of static electricity, there was little improvement in theoretical understanding of lightning (in particular how it was generated) for more than 150 years. The impetus for new research came from the field of power engineering: as power transmission lines came into service, engineers needed to know much more about lightning in order to adequately protect lines and equipment. Electrostatics (also known as static electricity) is the branch of physics that deals with the phenomena arising from what seem to be stationary electric charges. ... This article or section does not cite its references or sources. ... Power line redirects here. ...

Properties of lightning

World map showing frequency of lightning strikes, in flashes per km² per year (equal-area projection). Lightning strikes most frequently in the Democratic Republic of the Congo. Combined 1995–2003 data from the Optical Transient Detector and 1998–2003 data from the Lightning Imaging Sensor.

An average bolt of lightning carries a negative electric current of 40 kiloamperes (kA) (although some bolts can be up to 120 kA), and transfers a charge of five coulombs and 500 MJ, or enough energy to power a 100 watt lightbulb for just under two months. The voltage depends on the length of the bolt, with the dielectric breakdown of air being three million volts per meter; this works out to approximately one gigavolt (one billion volts) for a 300 m (1000 ft) lightning bolt. With an electric current of 100 kA, this gives a power of 100 terawatts. However, lightning leader development is not a simple matter of dielectric breakdown, and the ambient electric fields required for lightning leader propagation can be a few orders of magnitude less than dielectric breakdown strength. Further, the potential gradient inside a well-developed return-stroke channel is on the order of hundreds of volts per meter or less due to intense channel ionization, resulting in a true power output on the order of megawatts per meter for a vigorous return-stroke current of 100 kA ^[14]. For other uses, see Ampere (disambiguation). ... The coulomb (symbol: C) is the SI unit of electric charge. ... The joule (IPA: or ) (symbol: J) is the SI unit of energy. ... For other uses, see Watt (disambiguation). ... The term electrical breakdown has several similar but distinctly different meanings. ... Josephson junction array chip developed by NIST as a standard volt. ... Josephson junction array chip developed by NIST as a standard volt. ... This page lists examples of the power in watts produced by various different sources of energy. ...

Lightning heats nearby air to about 10,000 °C (18,000 °F) nearly instantly, which is almost twice the temperature of the Sun’s surface. The heating creates a shock wave that is heard as thunder.^[15] For other uses, see Celsius (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ...

The return stroke of a lightning bolt follows a charge channel only about a centimeter (0.5-in) wide — no wider than a pencil. Most lightning bolts are about 1.6 kilometers (1 mi) long. The longest recorded length was 190 kilometers (118 mi), sighted near Dallas, Texas.^[16]

Different locations have different potentials (voltages) and currents for an average lightning strike. For example, Florida, with the United States' largest number of recorded strikes in a given period during the summer season, has very sandy ground in some areas and conductive saturated mucky soil in others. As much of Florida lies on a peninsula, it is bordered by the ocean on three sides. The result is the daily development of sea and lake breeze boundaries that collide and produce thunderstorms. Arizona, which has very dry, sandy soil and a very dry air, has cloud bases as high as 1800-2100 m (6,000-7,000 ft) above ground level, and gets very long and thin purplish discharges which crackle; while Oklahoma, with cloud bases about 450-600 m (1,500-2,000 ft) above ground level and fairly soft, clay-rich soil, has big, blue-white explosive lightning strikes that are very hot (high current) and cause sudden, explosive noise when the discharge comes. The difference in each case may consist of differences in voltage levels between clouds and ground. Research on this is still ongoing.^{[citation needed]}

NASA scientists have found the radio waves created by lightning clear a safe zone in the radiation belt surrounding the earth. This zone, known as the Van Allen Belt slot, can potentially be a safe haven for satellites, offering them protection from the Sun's radiation.^[17][18][19] Van Allen radiation belts The Van Allen Radiation Belt is a torus of energetic charged particles (plasma) around Earth, held in place by Earths magnetic field. ...

Formation

Note

Positive lightning (a rarer form of lightning that originates from positively charged regions of the thundercloud) does not generally fit the following pattern.

Not to be confused with lighting. ...

Charge separation

The first process in the generation of lightning is charge separation.

Polarization mechanism hypothesis

The mechanism by which charge separation happens is still the subject of research, but one hypothesis is the polarization mechanism, which has two components:^[20]

1. Falling droplets of ice and rain become electrically polarized as they fall through the atmosphere's natural electric field;
2. Colliding ice particles become charged by electrostatic induction.

Ice and supercooled water are the keys to the process. Violent winds buffet tiny hailstones as they form, causing them to collide. When the hailstones hit ice crystals, some negative ions transfer from one particle to another. The smaller particles lose negative ions and become positive and the larger more massive particles gain negative ions and become negative.^[21] Electrostatic induction is a method by which an electrically charged object can be used to create an electrical charge in a second object, without contact between the two objects. ...

Electrostatic induction hypothesis

Another hypothesis is that opposite charges are driven apart by the above mechanism and energy is stored in the electric field between them. Cloud electrification appears to require strong updrafts which carry water droplets upward, supercooling them to between -10 and -20 °C. These collide with ice crystals to form a soft ice-water mixture called graupel. The collisions result in a slight positive charge being transferred to ice crystals, and a slight negative charge to the graupel. Updrafts drive lighter ice crystals upwards, causing the cloud top to accumulate increasing positive charge. The heavier negatively charged graupel falls towards the middle and lower portions of the cloud, building up an increasing negative charge. Charge separation and accumulation continue until the electrical potential becomes sufficient to initiate lightning discharges, which occurs when the gathering of positive and negative charges forms a sufficiently strong electric field. Supercool redirects here. ... Graupel can be any of the following types of solid-ice precipitation: hail - large chunks of ice such as from a strong or severe thunderstorm sleet - small pellets of raindrops that have frozen in mid-air, in winter or a thunderstorm snow pellets - when freezing fog forms 2-5mm balls... This article does not cite any references or sources. ...

There are several additional hypotheses for the origin of charge separation.^[22]

Leader formation

As a thundercloud moves over the Earth's surface, an equal but opposite charge is induced in the Earth below, and the induced ground charge follows the movement of the cloud. Wikipedia does not yet have an article with this exact name. ...

An initial bipolar discharge, or path of ionized air, starts from a negatively charged mixed water and ice region in the thundercloud. The discharge ionized channels are called leaders. The negative charged leaders, called a "stepped leader", proceed generally downward in a number of quick jumps, each up to 50 meters long. Along the way, the stepped leader may branch into a number of paths as it continues to descend. The progression of stepped leaders takes a comparatively long time (hundreds of milliseconds) to approach the ground. This initial phase involves a relatively small electric current (tens or hundreds of amperes), and the leader is almost invisible compared to the subsequent lightning channel. ... Wikipedia does not yet have an article with this exact name. ... A step leader is a path of ionized air which extends downward from a thundercloud during the initial stages of atmospheric breakdown during a lightning strike. ... One millisecond is one-thousandth of a second. ... This box:      Electric current is the flow (movement) of electric charge. ... For other uses, see Ampere (disambiguation). ...

When a stepped leader approaches the ground, the presence of opposite charges on the ground enhances the electric field. The electric field is highest on trees and tall buildings. If the electric field is strong enough, a conductive discharge (called a positive streamer) can develop from these points. This was first theorized by Heinz Kasemir. As the field increases, the positive streamer may evolve into a hotter, higher current leader which eventually connects to the descending stepped leader from the cloud. It is also possible for many streamers to develop from many different objects simultaneously, with only one connecting with the leader and forming the main discharge path. Photographs have been taken on which non-connected streamers are clearly visible. When the two leaders meet, the electric current greatly increases. The region of high current propagates back up the positive stepped leader into the cloud with a "return stroke" that is the most luminous part of the lightning discharge. A step leader is a path of ionized air which extends downward from a thundercloud during the initial stages of atmospheric breakdown during a lightning strike. ... A positive streamer is the bit of a lightning bolt that rises from the ground before the lightning strikes, often determining the path of the cloud-to-ground lightning. ... Luminous intensity is a measure of the energy emitted by a light source in a particular direction. ...

Discharge

Lightning sequence (Duration: 0.32 seconds)

When the electric field becomes strong enough, an electrical discharge (the bolt of lightning) occurs within clouds or between clouds and the ground. During the strike, successive portions of air become a conductive discharge channel as the electrons and positive ions of air molecules are pulled away from each other and forced to flow in opposite directions. Image File history File links Download high resolution version (2554x240, 222 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Lightning ... Image File history File links Download high resolution version (2554x240, 222 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Lightning ... An electrostatic discharge (ESD) is a sudden flow of electric current through a material that is normally an insulator. ...

The electrical discharge rapidly superheats the discharge channel, causing the air to expand rapidly and produce a shock wave heard as thunder. The rolling and gradually dissipating rumble of thunder is caused by the time delay of sound coming from different portions of a long stroke.^[23] In physics, superheating (sometimes referred to as boiling retardation, boiling delay, or defervescence) is the phenomenon in which a liquid is heated to a temperature higher than its standard boiling point, without actually boiling. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ...

Gurevich's runaway breakdown theory

Main article: Runaway breakdown

A theory of lightning initiation, known as the "runaway breakdown theory", proposed by Aleksandr Gurevich of the Lebedev Physical Institute in 1992 suggests that lightning strikes are triggered by cosmic rays which ionize atoms, releasing electrons that are accelerated by the electric fields, ionizing other air molecules and making the air conductive by a runaway breakdown, then "seeding" a lightning strike.^[24][25][26] This article or section does not cite its references or sources. ... The Lebedev Physical Institute of the Russian Academy of Sciences is a Russian research institute specializing in physics. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ...

Gamma rays and the runaway breakdown theory

Double lightning

It has been discovered in the past 15 years that among the processes of lightning is some mechanism capable of generating gamma rays, which escape the atmosphere and are observed by orbiting spacecraft. Brought to light by NASA's Gerald Fishman in 1994 in an article in Nature, these so-called Terrestrial Gamma-Ray Flashes (TGFs) were observed by accident, while he was documenting instances of extraterrestrial gamma ray bursts observed by the Compton Gamma Ray Observatory (CGRO). TGFs are much shorter in duration, however, lasting only ~1 ms. Image File history File linksMetadata Download high resolution version (3264x2448, 360 KB) Summary This picture was taken by me personally, from my balcony in Glyfada-Athens, during a storm. ... Image File history File linksMetadata Download high resolution version (3264x2448, 360 KB) Summary This picture was taken by me personally, from my balcony in Glyfada-Athens, during a storm. ... This article is about electromagnetic radiation. ... For other uses, see NASA (disambiguation). ... Nature is a prominent scientific journal, first published on 4 November 1869. ... Artists conception of gamma-ray burst and related phenomena. ...

Professor Umran Inan of Stanford University linked a TGF to an individual lightning stroke occurring within 1.5 ms of the TGF event,^[27] proving for the first time that the TGF was of atmospheric origin and associated with lightning strikes. Stanford redirects here. ...

CGRO recorded only about 77 events in 10 years; however, more recently the RHESSI spacecraft, as reported by David Smith of UC Santa Cruz, has been observing TGFs at a much higher rate, indicating that these occur ~50 times per day globally (still a very small fraction of the total lightning on the planet). The energy levels recorded exceed 20 MeV. Reuven Ramaty High Energy Solar Spectroscopic Imager (or RHESSI) is a NASA sixthSmall Explorer, launched on 5 February 2002. ... “UCSC” redirects here. ...

Scientists from Duke University have also been studying the link between certain lightning events and the mysterious gamma ray emissions that emanate from the Earth's own atmosphere, in light of newer observations of TGFs made by RHESSI. Their study suggests that this gamma radiation fountains upward from starting points at surprisingly low altitudes in thunderclouds. Duke University is a private coeducational research university located in Durham, North Carolina, United States. ...

Steven Cummer, from Duke University's Pratt School of Engineering, said, "These are higher energy gamma rays than come from the sun. And yet here they are coming from the kind of terrestrial thunderstorm that we see here all the time."

Early hypotheses of this pointed to lightning generating high electric fields at altitudes well above the cloud, where the thin atmosphere allows gamma rays to easily escape into space, known as "relativistic runaway breakdown", similar to the way sprites are generated. Subsequent evidence has cast doubt, though, and suggested instead that TGFs may be produced at the tops of high thunderclouds. Though hindered by atmospheric absorption of the escaping gamma rays, these theories do not require the exceptionally high electric fields that high altitude theories of TGF generation rely on. Upper-atmospheric lightning is an early term sometimes invoked by researchers to refer to a family of electrical breakdown phenomena that occurs well above the altitudes of normal lightning. ...

The role of TGFs and their relationship to lightning remains a subject of ongoing scientific study.

Re-strike

Lightning is a highly visible form of energy transfer.

High speed videos (examined frame-by frame) show that most lightning strikes are made up of multiple individual strokes. A typical strike is made of 3 to 4 strokes. There may be more.^[23] Image File history File links Size of this preview: 800 × 534 pixelsFull resolution (1600 × 1067 pixel, file size: 125 KB, MIME type: image/jpeg) Lightning strike at Swifts Creek, looking west in January 2007. ... Image File history File links Size of this preview: 800 × 534 pixelsFull resolution (1600 × 1067 pixel, file size: 125 KB, MIME type: image/jpeg) Lightning strike at Swifts Creek, looking west in January 2007. ...

Each re-strike is separated by a relatively large amount of time, typically 40 to 50 milliseconds. Re-strikes can cause a noticeable "strobe light" effect.^[23] An animation illustrating the effect of strobe light A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. ...

Each successive stroke is preceded by intermediate dart leader strokes again to, but weaker than, the initial stepped leader. The stroke usually re-uses the discharge channel taken by the previous stroke.^[23] A dart leader (also known as a continuous leader; may have been referred to by Feynman as a dark leader [citation needed]) is the cloud-to-ground movement of electrons which occurs just before a secondary lightning strike. ...

The variations in successive discharges are the result of smaller regions of charge within the cloud being depleted by successive strokes.^{[citation needed]}

The sound of thunder from a lightning strike is prolonged by successive strokes. For other uses, see Thunder (disambiguation). ...

Types of lightning

Cloud-to-cloud lightning, Steinenbronn, Germany

Some lightning strikes take on particular characteristics; scientists and the public have given names to these various types of lightning. Most lightning is streak lightning. This is nothing more than the return stroke, the visible part of the lightning stroke. Because most of these strokes occur inside a cloud, we do not see many of the individual return strokes in a thunderstorm. Image File history File linksMetadata Size of this preview: 800 × 526 pixelsFull resolution (1598 × 1051 pixel, file size: 231 KB, MIME type: image/jpeg) Lightning over Steinenbronn, Germany Photo: Valerie Imre (uploader) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this... Image File history File linksMetadata Size of this preview: 800 × 526 pixelsFull resolution (1598 × 1051 pixel, file size: 231 KB, MIME type: image/jpeg) Lightning over Steinenbronn, Germany Photo: Valerie Imre (uploader) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this... Steinenbronn is a town in the district of Böblingen in Baden-Württemberg in Germany. ...

The return stroke of a lightning bolt, which is the visible bolt itself, follows a charge channel only about a half-inch (1.3 cm) wide. Most lightning bolts are about a mile (1.6 km) long.^[28]

Positive lightning

See also: High_voltage#Lightning

Positive lightning, also known colloquially as a "bolt from the blue" makes up less than 5% of all lightning.^[29] It occurs when the leader forms at the positively charged cloud tops, with the consequence that a negatively charged streamer issues from the ground. The overall effect is a discharge of positive charges to the ground. Research carried out after the discovery of positive lightning in the 1970s showed that positive lightning bolts are typically six to ten times more powerful than negative bolts, last around ten times longer, and can strike tens of kilometres/miles from the clouds.^[30] The voltage difference for positive lightning must be considerably higher, due to the tens of thousands of additional metres/feet the strike must travel. During a positive lightning strike, huge quantities of ELF and VLF radio waves are generated.^[31] In electrical engineering High voltage refers to a voltage which is high. ... A Bolt from the Blue is a term referring to a form of lightning that strikes in clear blue skies. ... “km” redirects here. ... This article is about the unit of length. ... Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ... Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ...

As a result of their greater power, positive lightning strikes are considerably more dangerous. At the present time, aircraft are not designed to withstand such strikes, since their existence was unknown at the time standards were set, and the dangers unappreciated until the destruction of a glider in 1999.^[32] Flying machine redirects here. ... For other uses, see Glider (disambiguation). ...

Positive lightning is also now believed to have been responsible for the 1963 in-flight explosion and subsequent crash of Pan Am Flight 214, a Boeing 707.^{[citation needed]} Subsequently, aircraft operating in U.S. airspace have been required to have lightning discharge wicks to reduce the chances of a similar occurrence. Pan Am Flight 214 was a domestic scheduled passenger flight whose loss dispelled the myth that airliners in flight were impervious to damage from lightning strikes. ... The Boeing 707 is an American four-engine commercial passenger jet airliner developed by Boeing in the early 1950s. ...

Positive lightning has also been shown to trigger the occurrence of upper atmosphere lightning. It tends to occur more frequently in winter storms and at the end of a thunderstorm.^[33] A typical view of a winter storm. ... A shelf cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ...

An average bolt of positive lightning carries a current of up to 300 kA (kiloamperes) (about ten times as much current as a bolt of negative lightning), transfers a charge of up to 300 coulombs, has a potential difference up to 1 gigavolt (one billion volts), and lasts for hundreds of milliseconds, with a discharge energy of up to 300 GJ (gigajoules) (a billion joules).^{[citation needed]} For other uses, see Ampere (disambiguation). ... The coulomb (symbol: C) is the SI unit of electric charge. ... Josephson junction array chip developed by NIST as a standard volt. ... The joule (IPA: or ) (symbol: J) is the SI unit of energy. ...

Anvil-to-ground

One special type of cloud-to-ground lightning is anvil-to-ground lightning. It is a form of positive lightning, since it emanates from the anvil top of a cumulonimbus cloud where the ice crystals are positively charged. The leader stroke issues forth in a nearly horizontal direction until it veers toward the ground. These usually occur kilometers/miles from (often ahead) of the main storm and will sometimes strike without warning on a sunny day. An anvil-to-ground lightning bolt is a sign of an approaching storm, and if one occurs in a largely clear sky, it is known colloquially as a "Bolt from the blue."^[34] Cumulonimbus (Cb) is a type of cloud that is tall, dense, and involved in thunderstorms and other intense weather. ... A Bolt from the Blue is a term referring to a form of lightning that strikes in clear blue skies. ...

Cloud-to-cloud

Multiple paths of cloud-to-cloud lightning, Swifts Creek, Australia

Lightning discharges may occur between areas of cloud having different potentials without contacting the ground. These are most common between the anvil and lower reaches of a given thunderstorm. This lightning can sometimes be observed at great distances at night as so-called "heat lightning". In such instances, the observer may see only a flash of light without thunder. The "heat" portion of the term is a folk association between locally-experienced warmth and the distant lightning flashes. Image File history File links Size of this preview: 800 × 534 pixelsFull resolution (1600 × 1067 pixel, file size: 237 KB, MIME type: image/jpeg) Cloud to cloud lightning strike, March 2007, Swifts Creek If you are a (commercial) publisher and you want me to write you an email or paper... Image File history File links Size of this preview: 800 × 534 pixelsFull resolution (1600 × 1067 pixel, file size: 237 KB, MIME type: image/jpeg) Cloud to cloud lightning strike, March 2007, Swifts Creek If you are a (commercial) publisher and you want me to write you an email or paper... Swifts Creek is located between Omeo and Ensay on the Great Alpine Road of Victoria Categories: Australia-related stubs ...

Another terminology used for cloud-cloud or cloud-cloud-ground lightning is "Anvil Crawler", due to the habit of the charge typicallly originating from beneath or within the anvil and scrambling through the upper cloud layers of a thunderstorm, normally generating multiple branch strokes which are dramatic to witness. These are usually seen as a thunderstorm passes over you or begins to decay. The most vivid crawler behavior occurs in well developed thunderstorms that feature extensive rear anvil shearing.

Dry lightning

Dry lightning is a term in the United States for thunderstorms which produce no precipitation at the surface. This type of lightning is the most common natural cause of wildland fires. Dry lightning may also be referred to as heat lightning. Dry lightning is a term which is used in the United States to refer to thunderstorms which produce no rain at the surface. ...

Rocket lightning

Rocket Lightning, Queanbeyan, Australia

It is a form of cloud discharge, generally horizontal and at cloud base, with a luminous channel appearing to advance through the air with visually resolvable speed, often intermittently.^[35] Image File history File links Download high-resolution version (833x727, 30 KB) Lightning Storms over Queanbeyan NSW Australia February 2007 I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1. ... Image File history File links Download high-resolution version (833x727, 30 KB) Lightning Storms over Queanbeyan NSW Australia February 2007 I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1. ... The town of Queanbeyan in New South Wales, Australia is overshadowed by its proximity to the Australian federal capital city of Canberra. ... In astronomy, geography, geometry and related sciences and contexts, a plane is said to be horizontal at a given point if it is locally perpendicular to the gradient of the gravity field, i. ...

The movement has been compared to that of a skyrocket, hence its name. It is also one of the rarest of cloud discharges.^[36] A skyrocket is a type of firework that uses a solid rocket motor to rise quickly into the sky. ... For other uses, see Cloud (disambiguation). ...

Cloud-to-ground

Cloud-to-ground lightning is a great lightning discharge between a cumulonimbus cloud and the ground initiated by the downward-moving leader stroke. This is the second most common type of lightning, and poses the greatest threat to life and property of all known types.

Bead lightning

Bead lightning is a type of cloud-to-ground lightning which appears to break up into a string of short, bright sections, which last longer than the usual discharge channel. It is fairly rare. Several theories have been proposed to explain it; one is that the observer sees portions of the lightning channel end on, and that these portions appear especially bright. Another is that, in bead lightning, the width of the lightning channel varies; as the lightning channel cools and fades, the wider sections cool more slowly and remain visible longer, appearing as a string of beads.^[37][38]

Ribbon lightning

Ribbon lightning occurs in thunderstorms with high cross winds and multiple return strokes. The wind will blow each successive return stroke slightly to one side of the previous return stroke, causing a ribbon effect.

Staccato lightning

Staccato lightning is nothing more than a leader stroke with only one return stroke.

Ground-to-cloud lightning

Ground-to-cloud lightning is a lightning discharge between the ground and a cumulonimbus cloud from an upward-moving leader stroke.

Ball lightning

Main article: Ball lightning

Ball lightning is described as a floating, illuminated ball that occurs during thunderstorms. They can be fast moving, slow moving or nearly stationary. Some make hissing or crackling noises or no noise at all. Some have been known to pass through windows and even dissipate with a bang. Ball lightning has been described by eyewitnesses but rarely recorded by meteorologists.^[39] For other uses, see Ball lightning (disambiguation). ... Meteorology is the scientific study of the atmosphere that focuses on weather processes and forecasting. ...

The engineer Nikola Tesla wrote, "I have succeeded in determining the mode of their formation and producing them artificially".^[40] There is some speculation that electrical breakdown and arcing of cotton and gutta-percha wire insulation used by Tesla may have been a contributing factor, since some theories of ball lightning require the involvement of carbonaceous materials. Some later experimenters have been able to briefly produce small luminous balls by igniting carbon-containing materials atop sparking Tesla Coils. Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ... The term electrical breakdown has several similar but distinctly different meanings. ... An electric arc can melt calcium oxide. ... For other uses, see Cotton (disambiguation). ... Species About 100-120 species, including: Palaquium amboinense Palaquium barnesii Palaquium bataanense Palaquium beccarianum Palaquium borneense Palaquium burckii Palaquium clarkeanum Palaquium cochleariifolium Palaquium dasyphyllum Palaquium ellipticum Palaquium formosanum Palaquium galactoxylum Palaquium gutta Palaquium herveyi Palaquium hexandrum Palaquium hispidum Palaquium hornei Palaquium impressinervium Palaquium kinabaluense Palaquium lanceolatum Palaquium leiocarpum Palaquium lobbianum... Tesla Coil at Questacon, the Australian National Science Centre museum A Tesla coil (also teslacoil) is a type of resonant transformer, named after its inventor, Nikola Tesla. ...

Several theories have been advanced to describe ball lightning, with none being universally accepted. Any complete theory of ball lightning must be able to describe the wide range of reported properties, such as those described in Singer's book "The Nature of Ball Lightning" and also more contemporary research. Japanese research shows that several instances have been reported of ball lightning without any connection to stormy weather or lightning.

Ball lightning is typically 20 – 30 cm (8-12 inches) in diameter, but ball lightning several meters in diameter has been reported.^[41] Ball lightning has been seen in tornadoes, and has also been seen to split apart into two or more separate balls and recombine, and vertically-linked fireballs have been reported.^{[citation needed]} Ball lightning has carved trenches in the peat swamps in Ireland.^{[citation needed]} Because of its strange behavior, ball lightning has been mistaken for a UFO by many witnesses. One theory that may account for this wider spectrum of observational evidence is the idea of combustion inside the low-velocity region of axisymmetric (spherical) vortex breakdown of a natural vortex (e.g., the 'Hill's spherical vortex').^[42] This article is about the weather phenomenon. ... Peat in Lewis, Scotland Peat is an accumulation of partially decayed vegetation matter. ... This article does not cite any references or sources. ... UFO can mean: Unidentified flying object United Future Organization, a Japanese-Brazilian electronic jazz band UFO, the rock band that previously featured Michael Schenker UFO, the Gerry Anderson TV series United Farmers of Ontario, a political party that formed the government in Ontario from 1919 to 1923 U.F.O... This article is about the chemical reaction combustion. ... Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex (pl. ... A vortex ring is a mass of moving fluid moving through the same or different fluid where the flow pattern takes on a donut shape. ...

Ball lightning apparently is created when lightning strikes silicon in soil, and has been created in a lab in this manner.^[43]

Upper-atmospheric

Reports by scientists of strange lightning phenomena above storms date back to at least 1886. However, it is only in recent years that fuller investigations have been made.

Sprites

Main article: Upper-atmospheric lightning#Sprites

Sprites are now well-documented electrical discharges that occur high above some types of thunderstorms. They appear as luminous reddish-orange or greenish-blue, plasma-like flashes, last longer than normal lower stratospheric discharges (typically around 17 milliseconds), and are triggered by the discharges of positive lightning between the thundercloud and the ground.^[31] Sprites often occur in clusters of two or more, and typically span the distance from 50 miles (80 km) to 90 miles (145 km) above the earth, with what appear to be tendrils hanging below, and branches reaching above. A 2007 paper reports that the apparent tendrils and branches of sprites are actually formed by bright streamer heads of less than 140 m diameter moving up or down at 1 to 10 percent of the speed of light.^[44] The abstract is publicly accessible.^[45][46][47]

Sprites may be horizontally displaced by up to 30 miles (48 km) from the location of the underlying lightning strike, with a time delay following the lightning that is typically a few milliseconds, but on rare occasions may be up to 100 milliseconds. Sprites are sometimes, but not always, preceded by a sprite halo, a broad, pancake-like region of transient optical emission centered at an altitude of about 47 miles (76 km) above lightning.^[48] Sprite halos are produced by weak ionization from transient electric fields of the same type that causes sprites, but which are insufficiently intense to exceed the threshold needed for sprites. Sprites were first photographed on July 6, 1989 by scientists from the University of Minnesota. Several years after their discovery they were named after the mischievous sprite (air spirit) Puck in Shakespeare's Midsummer Night's Dream. Upper-atmospheric lightning is an early term sometimes invoked by researchers to refer to a family of electrical breakdown phenomena that occurs well above the altitudes of normal lightning. ... For other uses, see Plasma. ... The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ... This article is about the oldest and largest campus of the University of Minnesota. ... Wikipedia does not yet have an article with this exact name. ... Midsummer Nights Dream is the second episode of the Oh My Goddess! OVA series, and was originally released on 1993-05-21. ...

Recent research carried out at the University of Houston in 2002 indicates that some normal (negative) lightning discharges produce a sprite halo, the precursor of a sprite, and that every lightning bolt between cloud and ground attempts to produce a sprite or a sprite halo.^{[citation needed]} Research in 2004 by scientists from Tohoku University found that very low frequency emissions occur at the same time as the sprite, indicating that a discharge within the cloud may generate the sprites.^[45] For other system schools, see University of Houston System. ... This article is Tohoku University in Japan. ... Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ...

Blue jets

Blue jets differ from sprites in that they project from the top of the cumulonimbus above a thunderstorm, typically in a narrow cone, to the lowest levels of the ionosphere 25 miles (40 km) to 30 miles (48 km) above the earth.^{[citation needed]} They are also brighter than sprites and, as implied by their name, are blue in color. They were first recorded on October 21, 1989, on a video taken from the space shuttle as it passed over Australia, and subsequently extensively documented in 1994 during aircraft research flights by the University of Alaska.^[49][50][47] Relationship of the atmosphere and ionosphere The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation. ... is the 294th day of the year (295th in leap years) in the Gregorian calendar. ... Year 1989 (MCMLXXXIX) was a common year starting on Sunday (link displays 1989 Gregorian calendar). ... This article is about the space vehicle. ...

On September 14, 2001, scientists at the Arecibo Observatory photographed a huge jet double the height of those previously observed, reaching around 50 miles (80 km) into the atmosphere. The jet was located above a thunderstorm over the ocean, and lasted under a second. Lightning was initially observed traveling up at around 50,000 m/s in a similar way to a typical blue jet, but then divided in two and sped at 250,000 m/s to the ionosphere, where they spread out in a bright burst of light.^[51] On July 22, 2002, five gigantic jets between 60 and 70 km (35 to 45 miles) in length were observed over the South China Sea from Taiwan, reported in Nature.^[49] The jets lasted under a second, with shapes likened by the researchers to giant trees and carrots.^{[citation needed]} is the 257th day of the year (258th in leap years) in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... The Arecibo Observatory is located approximately 9 miles south-southwest from Arecibo, Puerto Rico (near the extreme southwestern corner of Arecibo pueblo). ... is the 203rd day of the year (204th in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... Filipino name Tagalog: Timog Dagat Tsina (Dagat Luzon for the portion within Philippine waters) Malay name Malay: Laut China Selatan Portuguese name Portuguese: Mar da China Meridional Vietnamese name Vietnamese: The South China Sea is a marginal sea south of China. ...

In 2001, the Arecibo scientists modeled the blue-jet phenomenon to better understand how it works. It is like an electron avalanche that can flood up toward the ionosphere or slide earthward, depending on the electric field direction. Intense hail may trigger the avalanche. The field accelerates the electrons and slams them into air molecules. The molecules break down into ions and free