Editing Lightning (section)

== Effects ==
A lightning strike can unleash a variety of effects, some temporary, including very brief emission of light, sound and electromagnetic radiation, and some long-lasting, such as death, damage, and atmospheric and environmental changes.

=== Injury, damage and destruction ===
{{Main|Lightning strike}}
The immense amount of energy transferred in a lightning strike can have potentially devastating effect in a multitude of areas.

==== To nature ====
[[File: Explosionsartiger Dampfdruck zwischen Stamm und Rinde vom Blitzeinschlag sprengte Birkenrinde weg.jpg|thumb|Bark blown off of a Birch tree via explosive steam pressure between the trunk and bark from a lightning strike]]
[[File:Black walnut lightning strike.jpg|thumb|upright=.8|A strike mark on the trunk of a [[black walnut]] tree in [[Oklahoma]]]]
Objects struck by lightning experience heat and magnetic forces of great magnitude. Consequently:
* The heat created by lightning currents travelling through a tree may vaporize its sap, causing a steam explosion that rips off bark or even bursts the trunk.
* Similarly water in a fractured rock may be rapidly heated such that it splits further apart.<ref>{{Cite web |title=Foss, Kanina, ''New evidence on lightning strikes'' University of the Witwatersrand, Johannesburg, Press release, 15 October 2013 |url=http://www.wits.ac.za/newsroom/newsitems/201310/21737/news_item_21737.html |url-status=dead |archive-url=https://web.archive.org/web/20151005162551/http://www.wits.ac.za/newsroom/newsitems/201310/21737/news_item_21737.html |archive-date=October 5, 2015}}</ref><ref>{{Cite journal |last1=Knight |first1=Jasper |last2=Grab |first2=Stefan W. |year=2014 |title=Lightning as a geomorphic agent on mountain summits: Evidence from southern Africa |journal=Geomorphology |volume=204 |pages=61–70 |bibcode=2014Geomo.204...61K |doi=10.1016/j.geomorph.2013.07.029}}</ref>
* A struck tree may catch fire, or a [[forest fires|forest fire]] may be started. See also ''fire lightning'' below.
* As lightning travels through sandy soil, the soil surrounding the [[plasma channel]] may melt, forming tubular structures called [[fulgurite]]s.

==== To man-made structures and their contents ====
Buildings or tall structures hit by lightning may be damaged as the lightning seeks unimpeded paths to the ground. By safely conducting a lightning strike to the ground, a lightning protection system, usually incorporating at least one [[lightning rod]], can greatly reduce the probability of severe property damage. [[surge protector|Surge protection devices]] (SPDs) can additionally or alternatively be used to help protect electrical installations from lightning induced electrical surges that risk damaging or destroying electrical equipment or starting a fire. Electrical fires obviously threaten not only structures but all assets, personal possessions, and living beings (people, pets and livestock) within. What, if any, protection system a building or structure requires is determined through a risk assessment. Threats to structures come not only from direct strikes to the structure itself, but also from direct or indirect strikes to connected electrically conductive services (electrical power lines; communication lines; water/gas pipes), or even to the surrounding area from which a surge may reach a service connection as it spreads out into the ground.

==== To aircraft ====
Aircraft are highly susceptible to being struck due to their metallic fuselages, but lightning strikes are generally not dangerous to them.<ref>{{Cite web|title=What happens when lightning strikes an airplane?|url=https://www.scientificamerican.com/article/what-happens-when-lightni/|date=August 14, 2006|website=Scientific American}}</ref> Due to the conductive properties of [[aluminium alloy]], the fuselage acts as a [[Faraday cage]]. Present day aircraft are built to be safe from a lightning strike and passengers will generally not even know that it has happened. However, there have been suspicions that lightning strikes can ignite fuel vapor and cause explosion,{{citation needed|date=December 2024}} and nearby lightning can momentarily blind the pilot and cause permanent errors in [[magnetic compass]]es.<ref name="AWH">{{cite web |title=FAA-H-8083-28A, Aviation Weather Handbook |url=https://www.faa.gov/regulationspolicies/handbooksmanuals/aviation/faa-h-8083-28a-aviation-weather-handbook |publisher=[[Federal Aviation Administration]] |access-date=24 December 2024 |pages=22–7}}</ref>

==== To living beings ====
Although 90 percent of people struck by lightning survive,<ref name="Outside 2014-09-22">{{cite web|url=http://www.outsideonline.com/outdoor-adventure/nature/The-Body-Electric.html|title=Lightning-Strike Survivors Tell Their Stories|last1=Jabr|first1=Ferris|date=September 22, 2014|work=[[Outside (magazine)|Outside]]|access-date=September 28, 2014|url-status=dead|archive-url=https://web.archive.org/web/20140928220906/http://www.outsideonline.com/outdoor-adventure/nature/The-Body-Electric.html|archive-date=September 28, 2014}}</ref> humans and other animals struck by lightning may suffer [[Lightning injuries|severe injury]] due to internal organ and nervous system damage.

=== Noise (Thunder) ===
{{main|Thunder}}

Because the electrostatic discharge of terrestrial lightning superheats the air to plasma temperatures along the length of the discharge channel in a short duration, [[kinetic theory of gases|kinetic theory]] dictates gaseous molecules undergo a rapid increase in pressure and thus expand outward from the lightning creating a [[shock wave]] audible as thunder. Since the sound waves propagate not from a single point source but along the length of the lightning's path, the sound origin's varying distances from the observer can generate a rolling or rumbling effect. Perception of the sonic characteristics is further complicated by factors such as the irregular and possibly branching geometry of the lightning channel, by [[echo (phenomenon)|acoustic echoing]] from terrain, and by the usually multiple-stroke characteristic of the lightning strike.<ref>{{cite web |url=https://www.nationalgeographic.com/environment/article/lightning |work=[[National Geographic]] |title=Lightning|date=October 9, 2009 }}</ref> Thunder is heard as a rolling, gradually dissipating rumble because the sound from different portions of a long stroke arrives at slightly different times.<ref name=autogenerated1>[[#Uman|Uman (1986)]] pp. 103–110</ref>

Lightning at a sufficient distance may be seen and not heard; there is data that a lightning storm can be seen at over {{convert|100|mi|km|order=flip|abbr=in}} whereas the thunder travels about {{convert|20|mi|km|order=flip|abbr=in}}. Anecdotally, there are many examples of people describing a 'storm directly overhead' or 'all-around' and yet 'no thunder'. Since thunderclouds can be up to {{convert|20|km|mi|abbr=in}} high,<ref>{{Cite web|url=https://factfile.org/10-facts-about-cumulonimbus-clouds|title = 10 Facts about Cumulonimbus Clouds|date = May 17, 2016}}</ref> lightning occurring high up in the cloud may appear close but is actually too far away to produce noticeable thunder.

==== The distance approximation trick ====
[[Speed of light|Light travels]] at about {{cvt|300,000,000|m/s}}, while [[speed of sound|sound]] only travels through air at about {{cvt|343|m/s}}. An observer can approximate the distance to the strike by timing the interval between the visible lightning and the audible thunder it generates. A lightning flash preceding its thunder by one second would be approximately {{convert|343|m|mi|abbr=in}} away; thus a delay of three seconds would indicate a distance of about {{convert|1|km|mi|abbr=in}}; while a flash preceding thunder by five seconds would indicate a distance of roughly {{convert|1|mi|km|abbr=out}}. Consequently, a lightning strike observed at a very close distance will be accompanied by a sudden clap of thunder, with almost no perceptible time lapse, possibly accompanied by the smell of [[ozone]] (O<sub>3</sub>).

=== Electromagnetic radiation and interference ===
Electromagnetic waves are emitted in a variety of wavelengths, most obviously that of visible light – the big bright flash. This emitted radiation results partly from [[black-body radiation]] due to the temperature increase caused by electrical resistance of the air,<ref name="Kieu2020">{{cite journal |last1=Kieu |first1=N. |last2=Gordillo-Vázquez |first2=F. J. |last3=Passas |first3=M. |last4=Sánchez |first4=J. |last5=Pérez-Invernón |first5=F. J. |last6=Luque |first6=A. |last7=Montanyá |first7=J. |last8=Christian |first8=H. |title=Submicrosecond Spectroscopy of Lightning-Like Discharges: Exploring New Time Regimes |journal=Geophysical Research Letters |date=16 August 2020 |volume=47 |issue=15 |pages=e2020GL088755 |doi=10.1029/2020GL088755|pmid=32999518 |pmc=7507749 |bibcode=2020GeoRL..4788755K |hdl=10261/218540 |hdl-access=free }}</ref> and partly for other reasons that are still being actively researched.<ref name="AIP2025">{{cite web |title=Explaining high-frequency radio waves generated during lightning strikes |url=https://ww2.aip.org/scilights/explaining-high-frequency-radio-waves-generated-during-lightning-strikes |website=AIP |access-date=3 February 2025 |language=en |date=2 September 2022}}</ref>

====Radio frequency radiation====
{{further|Radio atmospheric signal|label1=Radio atmospheric|Whistler (radio)|label2=Whistler|Schumann resonances}}

Lightning discharges generate radio-frequency electromagnetic waves which can be received thousands of kilometers from their source. The discharge by itself is relatively simple short-lived [[dipole]] source that creates a single electromagnetic pulse with a duration of about 1 ms and a wide spectral density. 
In the absence in the nearby environment of materials with [[Permeability (electromagnetism)|magnetic]] or [[Permittivity|electrical]] interaction properties, at a large distances in a [[Near and far field|far field]] zone, the electromagnetic wave will be proportional to the second derivation of the discharge current.<ref>{{cite book|last1=Landau|first1=Lev D|author1-link=Lev Landau|last2=Lifshitz|first2=Evgeny M|author2-link=Evgeny Lifshitz|title=[[Course of Theoretical Physics|The Classical Theory of Fields]]|volume=2|edition=4th|publisher=Butterworth-Heinemann|date=1975|isbn=978-0-7506-2768-9}}</ref> This is what happens with high-altitude discharges or discharges over areas of a dry land.
{{multiple image
 | align=center
 | total_width=800
 | image_gap=12
 | image1=
 | caption1=A single unaffected discharge over a dry land.
 | image2=
 | caption2=A discharge above conductive ground that induced local [[Eddy current]]s.
 | image3=
 | caption3=A discharge above [[ocean]]ic waters triggered [[resonance]] oscillations.
 | footer=Electromagnetic signals in a 10 Hz to 4 kHz frequency range produced by three different lightning discharges occurring thousands of kilometers away from the same registering station.<ref>{{cite web |url=https://hmicom.com/Archive/X3PE2ANC|title=Electromagnetic field records taken August 2016 near Stewart BC, Canada.|last=Issinski|first=A.|date=2016-08-28}}</ref> The lightning's local environment altered the shape of the received [[Near and far field|far field]] signal.
}}
In other cases, the surrounding environment will change the shape of the source signal by absorbing some of its spectrum and converting it into a heat or re-transmitting it back as modified electromagnetic waves.<ref>{{cite book|last1=Landau|first1=Lev D|author1-link=Lev Landau|last2=Lifshitz|first2=Evgeny M|author2-link=Evgeny Lifshitz|last3=Pitaevskii|first3=Lev P|author3-link=Lev Pitaevskii|title=[[Course of Theoretical Physics|Electrodynamics of Continuous Media]]|volume=8|edition=2nd|publisher=Butterworth-Heinemann|date=1984|isbn=978-0-7506-2634-7}}</ref>

==== High-energy radiation ====
{{further|Terrestrial gamma-ray flash}}
The production of [[X-ray]]s by a bolt of lightning was predicted as early as 1925 by [[Charles Thomson Rees Wilson|C.T.R. Wilson]],<ref>{{cite journal | last1 = Wilson | first1 = C.T.R. | date = 1925 | title = The acceleration of beta-particles in strong electric fields such as those of thunderclouds | journal = Proceedings of the Cambridge Philosophical Society | volume = 22 |pages = 534–538 |bibcode = 1925PCPS...22..534W |doi = 10.1017/S0305004100003236 | issue = 4 | s2cid = 121202128 }}</ref> but no evidence was found until 2001/2002,<ref>{{Cite journal | last1 = Moore | first1 = C. B. | last2 = Eack | first2 = K. B. | last3 = Aulich | first3 = G. D. | last4 = Rison | first4 = W. | title = Energetic radiation associated with lightning stepped-leaders | doi = 10.1029/2001GL013140 | journal = Geophysical Research Letters | volume = 28 | issue = 11 | page = 2141 | year = 2001 |bibcode = 2001GeoRL..28.2141M | doi-access = free }}</ref><ref>{{Cite journal | last1 = Dwyer | first1 = J. R. | last2 = Uman | first2 = M. A. | last3 = Rassoul | first3 = H. K. | last4 = Al-Dayeh | first4 = M. | last5 = Caraway | first5 = L. | last6 = Jerauld | first6 = J. | last7 = Rakov | first7 = V. A. | last8 = Jordan | first8 = D. M. | last9 = Rambo | first9 = K. J. | last10 = Corbin | first10 = V. | last11 = Wright | first11 = B. | title = Energetic Radiation Produced During Rocket-Triggered Lightning | doi = 10.1126/science.1078940 | journal = Science | volume = 299 | issue = 5607 | pages = 694–697 | year = 2003 | pmid = 12560549 | url = http://www.lightning.ece.ufl.edu/PDF/Dwyer_et_al_2003.pdf | bibcode = 2003Sci...299..694D | s2cid = 31926167 | url-status = dead | archive-url = https://web.archive.org/web/20160304220240/http://www.lightning.ece.ufl.edu/PDF/Dwyer_et_al_2003.pdf | archive-date = March 4, 2016 | df = mdy-all | access-date = August 28, 2015 }}</ref><ref>Newitz, A. (September 2007) "Educated Destruction 101", ''Popular Science'', p. 61.</ref> when researchers at the [[New Mexico Institute of Mining and Technology]] detected X-ray emissions from an induced lightning strike along a grounded wire trailed behind a rocket shot into a storm cloud. In the same year, [[University of Florida]] and [[Florida Institute of Technology|Florida Tech]] researchers used an array of electric field and X-ray detectors at a lightning research facility in North Florida to confirm that natural lightning makes X-rays in large quantities during the propagation of stepped leaders. The cause of the X-ray emissions is still a matter for research, as the temperature of lightning is too low to account for the X-rays observed.<ref>[http://www.physorg.com/news135351802.html Scientists close in on source of X-rays in lightning] {{webarchive|url=https://web.archive.org/web/20080905120610/http://www.physorg.com/news135351802.html |date=September 5, 2008 }}, ''Physorg.com'', July 15, 2008. Retrieved July 2008.</ref><ref name=Sergio2013>{{cite web | url=http://www.sci-news.com/othersciences/geophysics/article00996.html | title=Scientists Explain Invisible 'Dark Lightning' | website=Sci-News.com | date=April 11, 2013 | access-date=July 9, 2013 | author=Prostak, Sergio | url-status=dead | archive-url=https://web.archive.org/web/20130620185324/http://www.sci-news.com/othersciences/geophysics/article00996.html | archive-date=June 20, 2013 | df=mdy-all }}</ref>

A number of observations by space-based telescopes have revealed even higher energy [[gamma ray]] emissions, the so-called [[terrestrial gamma-ray flash]]es (TGFs). These observations pose a challenge to current theories of lightning, especially with the recent discovery of the clear signatures of [[antimatter]] produced in lightning.<ref>{{Cite web|title=Signature of antimatter detected in lightning|url=https://www.sciencenews.org/article/signature-antimatter-detected-lightning|website=Science News|last=Cowen|first=Ron|date=November 6, 2009|access-date=July 28, 2023|archive-date=July 28, 2023|archive-url=https://web.archive.org/web/20230728171126/https://www.sciencenews.org/article/signature-antimatter-detected-lightning|url-status=live}}</ref> Recent research has shown that secondary species, produced by these TGFs, such as [[electrons]], [[positrons]], [[neutrons]] or [[protons]], can gain energies of up to several tens of MeV.<ref name="KohnEbert">{{cite journal|last1=Köhn |first1=C. |last2=Ebert |first2=U.|author2-link= Ute Ebert |title=Calculation of beams of positrons, neutrons and protons associated with terrestrial gamma-ray flashes |journal=[[J. Geophys. Res. Atmos.]] |date=2015 |volume=23 |issue=4 |doi=10.1002/2014JD022229 |pages=1620–1635|bibcode=2015JGRD..120.1620K |url=https://ir.cwi.nl/pub/23845 |doi-access=free }}</ref><ref name="KohnHarakeh">{{cite journal|last1=Köhn |first1=C. |last2=Diniz |first2=G. |last3=Harakeh |first3=Muhsin |title=Production mechanisms of leptons, photons, and hadrons and their possible feedback close to lightning leaders |journal=[[J. Geophys. Res. Atmos.]] |date=2017 |volume=122 |issue=2 |pages=1365–1383 |doi=10.1002/2016JD025445|pmid=28357174 |pmc=5349290 |bibcode=2017JGRD..122.1365K }}</ref>

=== Environmental changes ===
More permanent or longer-lasting environmental changes include the following.

==== Atmospheric chemistry ====
The very high temperatures generated by lightning lead to significant local increases in [[ozone]] and [[Nitrogen oxide|oxides of nitrogen]]. Each lightning flash in temperate and sub-tropical areas produces 7&nbsp;kg of {{NOx}} on average.<ref>{{cite magazine|url=https://www.sciencedaily.com/releases/2009/10/091030100022.htm|title=Lightning's 'NOx-ious' Impact On Pollution, Climate|magazine= Science News|access-date=August 4, 2018}}</ref> In the [[troposphere]] the effect of lightning can increase {{NOx}} by 90% and ozone by 30%.<ref>{{cite web|url=https://www.nasa.gov/centers/goddard/news/topstory/2003/0312pollution.html|publisher=NASA|title=Surprise! Lightning has big effect on atmospheric chemistry|access-date=August 4, 2018|archive-date=March 9, 2019|archive-url=https://web.archive.org/web/20190309075516/https://www.nasa.gov/centers/goddard/news/topstory/2003/0312pollution.html|url-status=dead}}</ref>

==== Ground fertilisation ====
Lightning serves an important role in the [[nitrogen cycle]] by oxidizing diatomic nitrogen in the air into [[nitrates]] which are deposited by rain and can fertilize the growth of plants and other organisms.<ref>{{cite journal | last1 = Bond | first1 = D.W. | last2 = Steiger | first2 = S. | last3 = Zhang | first3 = R. | last4 = Tie | first4 = X. | last5 = Orville | first5 = R.E. | year = 2002 | title = The importance of NOx production by lightning in the tropics | journal = Atmospheric Environment | volume = 36 | issue = 9| pages = 1509–1519 | doi=10.1016/s1352-2310(01)00553-2| bibcode = 2002AtmEn..36.1509B }}</ref><ref>Pickering, K.E., Bucsela, E., Allen, D, Cummings, K., Li, Y., MacGorman, D., Bruning, E. 2014. Estimates of Lightning NOx Production Per Flash from OMI NO2 and Lightning Observations. XV International Conference on Atmospheric Electricity, 15–20, June 2014.</ref>

==== Induced permanent magnetism ====
The movement of electrical charges produces a magnetic field (see [[electromagnetism]]). The intense currents of a lightning discharge create a fleeting but very strong magnetic field. Where the lightning current path passes through rock, soil, or metal these materials can become permanently magnetized. This effect is known as lightning-induced [[Remanence|remanent]] magnetism, or LIRM. These currents follow the least resistive path, often horizontally near the surface<ref>{{cite journal|title=The Re-magnetization of a Surface Outcrop by Lightning Currents|doi=10.1111/j.1365-246X.1961.tb02963.x|date=1961|last1=Graham|first1=K.W.T.|journal=[[Geophysical Journal International]]|volume=6|issue=1|page=85|bibcode = 1961GeoJ....6...85G |doi-access=free}}</ref><ref>Cox A. (1961). [http://pubs.usgs.gov/bul/1083e/report.pdf Anomalous Remanent Magnetization of Basalt] {{webarchive|url=https://web.archive.org/web/20130529011301/http://pubs.usgs.gov/bul/1083e/report.pdf |date=May 29, 2013 }}. U.S. Geological Survey Bulletin 1038-E, pp. 131–160.</ref> but sometimes vertically, where faults, ore bodies, or ground water offers a less resistive path.<ref>Bevan B. (1995). [https://www.researchgate.net/profile/Bruce-Bevan/publication/318826400_Magnetic_surveys_and_lightning/links/59807da84585156238facc4d/Magnetic-surveys-and-lightning.pdf "Magnetic Surveys and Lightning"]. ''Near Surface Views'' (newsletter of the Near Surface Geophysics section of the Society of Exploration Geophysics). October 1995, pp. 7–8.</ref> One theory suggests that [[lodestone]]s, natural magnets encountered in ancient times, were created in this manner.<ref>{{cite journal |doi=10.1029/1999GL900496 |first=Peter |last=Wasilewski |author2=Günther Kletetschka |title=Lodestone: Nature's only permanent magnet – What it is and how it gets charged |url=http://lep694.gsfc.nasa.gov/gunther/gunther/Wasilewski1999.pdf |archive-url=https://web.archive.org/web/20061003193325/http://lep694.gsfc.nasa.gov/gunther/gunther/Wasilewski1999.pdf |archive-date=October 3, 2006 |journal=[[Geophysical Research Letters]] |volume=26 |issue=15 |pages=2275–78 |date=1999 |access-date=July 13, 2009| url-status=dead |bibcode = 1999GeoRL..26.2275W | s2cid=128699936}}</ref>

Lightning-induced magnetic anomalies can be mapped in the ground,<ref>{{Cite journal |last1=Sakai |first1=H. S. |last2=Sunada |first2=S. |last3=Sakurano |first3=H. |date=1998 |title=Study of Lightning Current by Remanent Magnetization |journal=Electrical Engineering in Japan |volume=123 |issue=4 |pages=41–47 |doi=10.1002/(SICI)1520-6416(199806)123:4<41::AID-EEJ6>3.0.CO;2-O}}</ref><ref>[http://www.archaeophysics.com/pubs/LIRM.html Archaeo-Physics, LLC | Lightning-induced magnetic anomalies on archaeological sites] {{webarchive|url=https://web.archive.org/web/20071012080847/http://www.archaeophysics.com/pubs/LIRM.html |date=October 12, 2007 }}. Archaeophysics.com. Retrieved on June 23, 2012.</ref> and analysis of magnetized materials can confirm lightning was the source of the magnetization<ref>{{Cite journal |last=Maki |first=David |date=2005 |title=Lightning strikes and prehistoric ovens: Determining the source of magnetic anomalies using techniques of environmental magnetism |journal=Geoarchaeology |volume=20 |issue=5 |pages=449–459 |doi=10.1002/gea.20059 |bibcode=2005Gearc..20..449M |url=http://www.archaeophysics.com/pubs/lightning-oven.pdf |url-status=dead |archive-url=https://web.archive.org/web/20130515025335/http://www.archaeophysics.com/pubs/lightning-oven.pdf |archive-date=May 15, 2013  |citeseerx=10.1.1.536.5980 |s2cid=52383921 |access-date=November 1, 2017 }}</ref> and provide an estimate of the peak current of the lightning discharge.<ref>{{Cite journal |last1=Verrier |first1=V. |last2=Rochette |first2=P. |date=2002 |title=Estimating Peak Currents at Ground Lightning Impacts Using Remanent Magnetization |journal=[[Geophysical Research Letters]] |volume=29 |issue=18 |page=1867 |doi=10.1029/2002GL015207|bibcode = 2002GeoRL..29.1867V |s2cid=128577288 |doi-access=free }}</ref>

=== Magnetic hallucinations ===

Research at the [[University of Innsbruck]] has calculated that magnetic fields generated by plasma may induce [[hallucinations]] in subjects located within {{cvt|200|m}} of a severe lightning storm, like what happened in [[Transcranial magnetic stimulation]] (TMS).<ref>{{cite web | url=https://www.technologyreview.com/s/418887/magnetically-induced-hallucinations-explain-ball-lightning-say-physicists/ |title = Magnetically Induced Hallucinations Explain Ball Lightning, Say Physicists}}</ref>