Talk:Lightning
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[edit] Ball lightning "(the xyz?)"?
Is this really necessary? It doesn't fit the tone of wikipedia at all... in fact the entire ball lightning section reads pretty badly.--Badharlick 23:46, 22 May 2006 (UTC)
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- would someone please remove the section on ball lightning. let's get serious here... this is Wikipedia... Wikipedians, have some standards... please tell me that when this aticle was nominate as "good," that was not present. we have a name for phenomenon that only 3 percent of society experience, hearsay. there are no reliable citations. Or who wants to help me finish the section on alien abductions? really, a lot of really normal (non"expert") personalities expeiience it. it's real. get it? or is this gonna be as fruitful as reasoning with a theist?
====antip8ri8 //sometime before xmas/ —The preceding unsigned comment was added by Antip8ri8 (talk • contribs) 03:38, 4 December 2006 (UTC). i cant hyperlink, as i have no braket on my cell. so, no markup for yours truely. believe me, i would. for now, username::antip8ri8
[edit] lenticular mammatus
As an aside, apparantly this is a hybrid cloud between lenticular and mammatus, and is associated with thunder storms... anyone have any ideas on it or whether there should be a seperate article on it?--Badharlick 23:46, 22 May 2006 (UTC)
"Aerospace America" April 2006: Electric hurricanes puzzle reasearchers (Pg 26-27). According to the article, some hurricanes have had lightning, including Rita, Katrina, and Emily, all of which had alot of lightning strikes reported. The hurricanes did not hit mountains causing vert. updrafts...Worth mentioning?
[edit] General (uncategorised)
"Some repeat lightning strike victims claim that lightning can choose its target, although this theory is entirely disregarded by the scientific community. "
Is this really necessary??
err...why is my post on top?
The lightning page explains producing/separating electric charge by triboelectricity process among ice particles (or dust). But the triboelectricity page (and the Van de Graaff page), says that the rubbing particles must be of different material to produce/separate electrical charge. If so, the ice particles (or dust) being of the same material could not produce static electricity. These pages seem to contradict one another. Any comment? RS
- First, nobody understands how regions of charge in thunderstorms are produced. It's still an open question in physics. There are several theories, but each of them has problems, chief of which is that freezing water SEEMS to play a critical role, yet some rare clouds develop charge at far above 0C degrees. Any popular book that states how lightning really works is wrong. Instead try Dr. Martin Uman's book "Lightning." That said... the most accepted current theory involves charge separation between water and ice, with half-frozen raindrops called "graupel" spalling off ice shards. If I understand correctly, the tiny ice shards end up charged, with the raindrop developing equal and opposite charge, then the large raindrops outrun the tiny ice shards, causing huge positive and negative regions to appear within the storm. --Wjbeaty 18:45, Mar 2, 2005 (UTC)
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- What about lightning in the atmosphere on Mars? However rare that may be, it's bound to be possible. Does the presence of iron oxide ions tend to dampen the phenomenon of lightning, or enhance it?
The article states that the charge separation occurs partly due to polarization - this is obviously wrong. Polarization would cause negative charge to move towards the positively charged upper atmosphere and positive charge towards earth - but the opposite is true. 193.171.121.30 17:05, 10 Mar 2005 (UTC)
- Theories all, however I believe you have forgotten the presence of a very strong thunderstorm updraft that can be in excess of 50 m/s in supercell thunderstorms. These updrafts could easily move things against the very weak natural electric field between the clouds and the earth. Keep in mind that the largest measured electrical field to date in a thunderstorm cloud is nowhere near the 30kV • cm-1required for the breakdown voltage of air. Clegett 01:26, 16 July 2006 (UTC)
It seems quite obvious to anyone familiar with triboelectricity that charge separation must involve two different materials. Can ice and water be considered different materials? Most likely not, but there seems to be a lack of scientific data specific to these states of matter to draw a conclusion. Modern research has detected rather large X-ray and gamma-ray bursts during lightning discharges, suggesting that the source of the energy may be more of a cosmic nature than previously believed. Just how much energy is imparted to the charges by the cosmic influence has yet to be discovered.
My personal theory, and a long-standing one is that the charge imparted to a cloud is strongly related to the vertical climb of the cloud during an inversion, thus exposing the top of the cloud to more intense cosmic energy. As the cloud falls back towards the earth in the form of rain, the magnificent charge difference imparted by the cosmic bombardment, is manifested during it's approach in the form of powerful discharges, or lightning. [CBFuller, 5:52AM, 2-04-06]
Some say that lightning can pass through glass windows. Othes are sceptical. JRG
Apologies for accidental deletion of this page. I have no idea how it happened, I can assure you it was not intentional. Sorry again. --/Mat 19:24, 4 Apr 2004 (UTC)
Odd - someone else managed to change this page to a null entry (like I apparently did) - anyone know if this is a user-error, browser error, page-error or wiki error? --/Mat 15:34, 9 Apr 2004 (UTC)
I apologise for making remarks (on lightnings are formed/piezoelectricity). I accept that you "editors" must work within the cornerstones of some standards, but let me as an active scientist in this field, also say that there already _are_ mentioned plentyful of misunderstandings and references to sources with very little plausibility, to put it gently, on this page!
Firstly, on lightning rods. The principle to seek protection under high trees and "artificial earth" (e. g. copper covered roofs) has been known at least 2000 years. It is true that the work of Kleist and Musschenbroek started a "golden era" for the electricity research, but it is more than dubious that Franklin made the first modern lightning rod. The Moravian clergyman Prokop Divis was most likely earlier than Franklin and there might have been others (in e. g. France)!
Secondly, on lightning directions. There _are_ no cloud-to-earth lightnings with a preceeding discharge in the opposite direction. On rare occasions a cloud-to-earth lightning make use of a electrical leading volume of air, which previously was ionised by an earth-to-cloud lightning. Earth-to-cloud lightnings are not very common, but when they occur, it is due to a "displacement of the dialectricum". Normally, the strongest isolator is the air layer between the ground and the cloud. Again normally, this isolator is weakened when rain or hail starts to fall and the lightning is triggered. However, in rare situations, there is a very dry layer of earth well under the surface. This layer can act as a stronger dialectricum than the layer of air above the surface. This will lead to a certain negative charge of the surface layer of the earth and from this layer a discharge can take place towards a _new_ and fairly neutral cloud!
Thirdly, on ball lightnings. They are not at all rare. At least 3 % of all humans has observed the phenomenon. They are most likely the same phenomenon as _bead lightnings_ , where the bead lightning is what is recorded by photograpic film or the human eye, when the "ball" is helixing in its way. The thing is that ball lightnings start with a disc shape which turns into a spheric shape as it gets older and smaller, gets unstable and "explode". Thus bead lightnings are always "early"! Ball lightnings is often seen passing glass panes, normal lightnings will always find a better leader elsewhere! The size of ball lightnings is often extremly difficult to judge, but in final stage, before the explosion they usually end with, is at most 0.5 m.
I have a theory of my own, on ball lightnings are formed, but as it is _original reaearch_ , and even difficult to get verified, I will not reveal in this forum.
At last, my mission with this note has _not_ been that you should "write as I say", but maybe some of you find it worthwile to have in mind, when you approve the final version of this page!
Ragards John Larsson, Birkerød, Denmark, (jl[at]ing.dk)
[edit] Ozone
The ozone page says that lightning produces ozone. Has this ever been measured? JWSchmidt 05:20, 12 Apr 2004 (UTC)
- "Researcher Renyi Zhang of Texas A&M University helped lead a study on the impact of lightning, and the results are surprising: Lightning can ... increase ozone levels as much as 30 percent in the free troposphere, the area that extends 3-8 miles above the Earth's surface. " - from EurekAlert.
- People have known that lightning produces ozone since the days of Benjamin Franklin, if not earlier. It was the fact that man-made electric discharges caused the same ozone smell as lightning that led Franklin to investigate the electrical causes of lightning. (Source: Ask A Scientist.)
- -- Heron 15:11, 27 May 2004 (UTC)
[edit] Lightning rods
I was under the impression that a lightning rod actually prevented lightning from striking, rather than providing a lower resistance conduction path. The idea is that the lightning rod allows charge to dissipate from the structure it is attached to, thus reducing the potential difference between the cloud and structure, reducing the chance of lightning striking that location... That said, I've also seen videos of lightning striking the tops of skyscrapers, so I'm not entirely confident this is their *only* purpose...
- There seem to be conflicting opinions about this. Benjamin Franklin believed that "the electrical fire would, I think, be drawn out of a cloud silently, before it could come near enough to strike". He proved that some charge was extracted "silently" from thunderclouds by a lightning rod, but this is not the same as preventing a lightning strike. HowStuffWorks says that "Regardless of whether or not a lightning-rod system is present, the strike will still occur. ".
- Franklin's theory suggested that pointed rods were better because they caused a silent discharge and prevented lightning strikes, while British scientists believed that blunt rods were better because they induced strikes to occur where they could be safely conducted to ground. The debate became polarised for political reasons, with Americans supporting Franklin's view and the British clinging to the opposite view. I suspect that this rivalry continues today. I don't want to take sides here, but I note an article in USA Today entitled "Researchers find that blunt lightning rods work best". I wouldn't be surprised to find other articles supporting the opposite point of view. -- Heron 12:31, 24 Jun 2004 (UTC)
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- I guess it would depend on the surroundings, a pointed rod should be better for sending out streamers (and by that "attracting" the lightning) because of the "concentrated" electric field at the point, but I'm not familiar enough with the electrical properties of air in very strong electrical fields to make a qualified remark really.--Deelkar 14:57, 9 Sep 2004 (UTC)
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- however, a lightning rod (either pointed or blunt) increases the probability of a somewhat controlled lightning strike, i.e. the lightning not hitting anything inflammable. However, if the lightning strikes near to a house, regardless of striking the rod or a tree or the Ground directly, there is a certain amount of EMP that can damage electronic equipment, even if it is protected or even disconnected. --Deelkar 15:04, 9 Sep 2004 (UTC)
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- Some facts never stated in the lightning rod controversy... a cloud-ground lightning streamer is triggered SEVERAL MILES UP, and the electric current sent out by a lightning rod is made of charged air and is subject to wind speed. How can a relatively small lightning rod have any effect on a gigantic stormcloud miles away? And since there is no hurricane-force wind coming out of the tips of lightning rods, how can the slow-moving charge sent out the rod ever reach the stormcloud at all? The obvious answer is that it can't. (Imagine that the tip of a lightning rod was emitting colored smoke which is attracted upwards. This "smoke" moves slowly, and if the wind is blowing, then it's wafted downstream faster than it can rise.) Early physicists were reasoning from analogy, where a sharp needle could easily discharge a charged metal ball from many inches away. But since the "electric wind" which discharges the metal ball only moves at inches per second, the analogy doesn't work for the immense distances involved in trying to discharge a storm cloud. Perhaps the charged air sent upwards by a lightning rod could deflect an incoming streamer. Or perhaps the mass of charged air could electrically shield the rod, so that the incoming streamer would trigger an answering streamer from some other building, thus "deflecting" the strike.
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- The accumulation of charge in the cloud produces a field around it that orients nearby molecules to have their ends pointing in the opposite direction of the potential field. For example, if a cloud has a large negative charge and the ground is neutral, then air molecules will point their positive ends towards the clouds and negative ends towards the ground. This process is nearly instantaneous. As more charge is built up in the cloud, more molecules will align themselves. There will be many possible paths from the cloud to the ground where all the molecules are aligned. Eventually one of these paths will have enough potential energy across it to tear the electrons from the molecules, forming a temporary plasma conductor in the air. This is when lightning actually strikes. It is more like a rubber band that has been stretched too far than a baseball that is hurled at the ground. The reason that a lightning rod works is that it provides a generally shorter distance to ground for the lightning, and greatly reduces the amount of resistance between the cloud and conducting ground (normally the lightning would have to go through rock, glass, trees, soccer players, whatever. A lightning rod is metal and has less resistance than these other substances). Since it is an electrically shorter distance, it will tend to be easier to break down the air between the lightning rod and the cloud instead of just the regular ground. Think of it as the difference between stretching a tiny rubber band to the breaking point and stretching a big rubber band to the breaking point. And of course, once the air breaks down, the charges in the ground and cloud are equal, so there is no longer a potential across the air, so there can be no more lightning until it builds up again. Edit - reading more of the argument: the reason that a lightning rod could reduce the chance of a lightning strike is that some work is done by the potential to align the molecules, and then a lot more work is done to "stretch" them apart. If you do enough work this way it should reduce the potential. --Ignignot 20:15, Mar 2, 2005 (UTC)
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speaking of franklin, according to the article on franklin the famous kite experiment may or may not have ever actually been performed, and was only mulled over as far as we know. either that article or this one is in error.
[edit] Positive lightning
The article comments on positive lightning: It occurs when the stepped leader forms at the positively charged cloud tops, with the consequence that a positively charged streamer issues from the ground. Shouldn't that read ... with the consequence that a negatively charged streamer issues from the negatively charged ground away from the cloud??? --Martin Rehker 13:00, 6 Aug 2004 (UTC)
- That link to a page of photos of positive lightning... doesn't the author mean UPWARDS lightning? Positive lightning is rare, and begins at cloud tops, while those photos clearly show cloud-base lightning (and there are several photos: NOT RARE.) Remove it?--Wjbeaty 05:16, 1 November 2005 (UTC)
[edit] image/streamer
since streamers sometimes (?) are visible, could it be that the faint light to the right was a streamer that did not connect to the cloud ligntning or the cloud-ground lightning to the right? --Deelkar 14:44, 9 Sep 2004 (UTC)
[edit] Confusing language in "History of lightning research"
I added the "confusing" boilerplate in response to the immensely confusing language used in the "History of lightning research" section. I had to read this section several times to understand it. It looks like the author was sitting in front of a thesaurus picking pretty words. I'm not an expert on Benjamin Franklin, but hopefully there's someone out there who can write about him while maintaining Wikipedia's standards of readability. --Aeki 01:12, 7 Apr 2005 (UTC)
- It's just old writing; by someone who never played with Nintendo or Sega games, who never used a computer to edit his writing, never saw a spell-checker or online thesaurus. But much more than that, even—someone who never even watched a television program in his whole life, likely. Never listened to the radio either. Never had electric lights in his house, never saw an electric outlet. This might be from the 1911 Encyclopædia Britannica, or something even older (and if from the Britannica, probably a holdover article from an earlier edition). Someone who didn't have the words in his vocabulary to deal well with the phenomenon of electricity. Sparks he'd seen, from fire and flint on steel more than from electricity; and he'd seen a Leyden jar. Gene Nygaard 02:23, 7 Apr 2005 (UTC)
Thanks for the humorous response, Gene. I was personally reminded of the English used in Mark Twain's The Prince and the Pauper. At any rate, the dialect used appears to be only in that section, so it'd be nice if someone born after the War of 1812 with knowledge of Franklin's experiment could bring it up-to-date. --Aeki 05:59, 7 Apr 2005 (UTC)
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- Hey, give the author a break, Leyden jars were probably a lot more common in 1828. (looks like the section was lifted from about half way down this page) -- Solipsist 07:20, 7 Apr 2005 (UTC)
Is it appropriate for us to be copy/pasting 177-year old texts from Project Gutenberg and saying "Poof! I have me a Wikipedia article!" like this? Nevermind that there's no citation of sources. I know it's public domain. Still, if we are basing our science articles in 2005 on texts that have become public domain because of their age, isn't that...misguided? I maintain that a current article on a scientific subject should at least be written in current language. --Aeki 07:35, 12 Apr 2005 (UTC)
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- No you're right, its one of the oldest examples I've seen. Quite a few articles are based on the 1911 Britannica, which is often seen as too old fashioned and out of date. We have templates to encourage updating that text. However, here the best course of action is probably to remove the section entirely and replace it with a stub. This text is most likely hampering people from writing a good history. -- Solipsist 08:37, 12 Apr 2005 (UTC)
- OK, I rewrote the Section in conſern in a more legible manner, using the previous Source, in the modern Language. 68.39.174.39 05:58, 16 Apr 2005 (UTC)
[edit] Commons
I made some work at commons and at least Image:Global Lightning Frequency.jpg should be integrated. --Saperaud 2 July 2005 11:12 (UTC)
[edit] What happened to the Facts?
..."Lightning Alley", a group of states in the American Southeast that collectively see more lightning strikes per year than any other place on Earth...
Whats up with the change in this sentence? The information is factually correct, the American Southeast does see more lightning strikes per year than any other place on earth. Why was this changed? TomStar81 03:32, 12 August 2005 (UTC)
I'd like to challenge the validity of this statement, it appears to contradict the NASA lightning strike frequency map, which clearly shows places in central Africa and South America with far more lightning strikes than anywhere in the U.S. Please amend or cite sources. Peter. 13:36, 20 October 2005 (Japan)
- My bet is that any tropcial area of the same size sees more lightening than the ligthening alley, they get a thunderstorm there at least once a day. In terms of lightenings per time and area (i.e. density) the record holder is a region in north Australia (forgotten where exactly) AFAIK. - Alureiter 13:02, 24 November 2005 (UTC)
- More data, found on [1]: "Florida is lightning capital of the United States." Mali said. Florida experiences lightning strikes at least 100 days per year.. This rules out the "world record", I'll remove it. The article also offers a different definition of ligthening alley: "Interstate 4 between Orlando and St. Petersburg is called lightning alley. There is more lightning activity on lightning alley than any other area in the U.S." - Alureiter 13:08, 24 November 2005 (UTC)
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- My thanks in resolving this. I started the research, but then had to abonden it due to increasing school work loads and falling grades. About ten minutes ago it occured to me to come back here and check on this to see if it was still a live issue. Sorry I did not do the work myself, it was my responsibility so to speak. And to Peter: You were right, and I was wrong. Congratulations, and thank you for correcting me. TomStar81 04:11, 22 January 2006 (UTC)
[edit] 'Heat' Lightning
I came to this page looking for this information. But found it elsewhere. I think it would be at home on this page
http://www.islandnet.com/~see/weather/whys/heatlightning.htm http://whyfiles.org/137lightning/applet/index.html
Namely that heat lightning is (or can be) unaccompanied by rain and thunder.
[edit] Ben Franklin
Did he really perform this stupidly dangerous experiment on lightning?? This casts some doubt [2]--Light current 03:50, 11 September 2005 (UTC)
- I don't see how that page casts any doubt on anything. It's just a bunch of oversimplifications. No one knew the danger of the experiment when Franklin first did it, though they would soon find out. --Deglr6328 04:08, 11 September 2005 (UTC)
How do we know he really performed the experiment. Did he write it down?--Light current 04:15, 11 September 2005 (UTC)
- Yes.--Deglr6328 06:43, 11 September 2005 (UTC)
Could you point me to the ref. I'd like to read it. Thanks--Light current 06:50, 11 September 2005 (UTC)
THis [3] seems to imply that Franklin never in fact performed this experimnent. The experiment is not mentioned in Franklins autobiography, and Franklin was well known to be a practical joker. He was also not pleased with the Royal Society in England for not recognising his other work. He sent over the paper to be read in England in his absence by his friend the well respected Joseph Priestly. THe paper was read and published in the proceedings of the Society. There is no other record of the experiment and no witnesses are quoted. In view of all this, I think we should modify the article to say that this experiment did not in fact take place and is a Myth!--Light current 02:35, 13 September 2005 (UTC)
- I don't think we can discount Franklin's research based on an article in "Kite Life" magazine... However, I have always wondered why he didn't just tie the kite to something! Halsteadk 07:29, 13 September 2005 (UTC)
What about there being no mention in his autobiography?. If you had performed this experiment, surely you would include it in yours!. Not a mention!!--Light current 12:25, 13 September 2005 (UTC)
Ben Franklins autobiography[4] Try to find the reference to Franklins performing the kite experiment!--Light current 14:16, 13 September 2005 (UTC)
The only ref I can find in it is this:
What gave my book the more sudden and general celebrity, was the success of one of its proposed experiments, made by Messrs. Dalibard and De Lor at Marly, for drawing lightning from the clouds. This engag'd the public attention every where. M. de Lor, who had an apparatus for experimental philosophy, and lectur'd in that branch of science, undertook to repeat what he called the Philadelphia Experiments; and, after they were performed before the king and court, all the curious of Paris flocked to see them. I will not swell this narrative with an account of that capital experiment, nor of the infinite pleasure I receiv'd in the success of a similar one I made soon after with a kite at Philadelphia, as both are to be found in the histories of electricity.
(my bolding)
Note that Franklin was not the first (if at all) to 'draw lightning from clouds'.--Light current 00:51, 14 September 2005 (UTC)
This thread looks like it has been inactive for a while, but here is the deal: Franklin himself didn't describe the kite experiment in any published work. However, he did describe how to build the kite in the book ("Experiments and Observations on Electricity") referenced above in his autobiography. His friend Joseph Priestly also gives the following account in "History and Present State of Electricity":
"At length, just as he was beginning to despair of his contrivance, he observed some loose threads of the hempen string to stand erect, and to avoid one another, just as if they had been suspended on a common conductor. Struck with this promising appearance, he immediately presented his knuckle to the key, and (let the reader judge of the exquisite pleasure he must have felt at that moment) the discovery was complete. He perceived a very evident electric spark. Others succeeded, even before the string was wet, so as to put the matter past all dispute, and when the rain had wet the string, he collected electric fire very copiously."
If anyone is interested, I have made a short essay "The Key to Electricity" (for the Penn University Press edition of the Autobiography) available here: [5] . --mweisberg 26 July 2006
This was part of a myth busted in MythBusters, and the verdict was: "With a wet kite string, there was a nice spark from the generator, to the kite, down the string, onto the key, and into the dummy Ben's finger. The heart monitor showed a lethal charge to Ben's heart. A real lightning bolt has a lot more charge, so it would be even less likely to survive: test 3 failed." ... "the first two parts of Franklin's experiment are plausible -- flying a kite in a thunderstorm and having a charge travel down the string -- but it's unlikely that Franklin would have been able to touch the key" -- Northgrove 09:27, 2 October 2006 (UTC)
FWIW, Saint Stephen's Church in Philadelphia (just south of 10th and Market) has a marker on it from the PA Historical Commission designating it as the spot where Franklin performed the experiment. Mpd 02:39, 14 December 2006 (UTC)
[edit] Does thunder always accompany lightning?
Not all lightning produces thunder. Thunder is a sound caused by the expanding gases around the discharge path. If there is no one around to hear these explosions, like in the upper atmoshpere, then, although gas expansion may occur, thunder is not produced. I dont believe the term thunder is scientifically defined and therfore should be removed from the definition in the lead para. Thoughts?--Light current 08:50, 21 September 2005 (UTC)
- Isn't this the same argument as the old saying "if a tree falls down in the woods and no-one is around to hear it, does it make a sound?". If the sound is still produced then it makes no difference whether anyone is around to make it. Halsteadk 11:52, 25 September 2005 (UTC)
Yes! Thunder is not a scientific term, but one used by Joe Public. Acoustic shock wave is more accurate--Light current 13:28, 25 September 2005 (UTC)
- I'd say, thunder is the acoustic phenomen that is created by the shock waves of a lightening bolt (and their echos). - Alureiter 16:25, 4 January 2006 (UTC)
[edit] Ball Lightning
Good edit on ball lightning and lots of good material added!--Light current 21:16, 24 September 2005 (UTC)
The ball lightning part of this article is below the standards of the rest in writing quality. e.g. please cite the "Japanese research" and change the "(the xyz?)" bits. i reccommend more ball lightning pictures. it shows people what it looks like.
[edit] new theories
Anybody know much about the new theories about lightning forming because of interaction from space? There were several articles on Newscientist.com a few months ago
[edit] Extremely dubious
- Rain is said to be heavier immediately after a bolt of lightning. The cause of this phenomenon is traceable to the bipolar aspect of the water molecule. The intense electric and magnetic field generated by a lightning bolt forces many of the water molecules in the air surrounding the stroke to line up. These molecules then spontaneously create localized chains of water (similar to nylon or other 'poly' molecules). These chains then form water droplets when the electric/magnetic field is removed. These drops then fall as intensified rain.
OK, it starts off with "is said to be" — a bad sign right there. It continues with a claim based on polywater, which is extremely implausible in any context. Finally, it concludes that polymerized water makes "intensified rain" which is "heavier" than normal. Huh? Anville 10:03, 12 October 2005 (UTC)
- If it's true, that electric or magnetic fields cause water molecules or water droplets to clog faster together (it doesn't matter if horizontally or vertically), such fields accelerate the formation of drops and thus cause more (or larger) drops to be created => more rain, what Joe Average calls "heavier". The author doesn't write polymerized water. I think (s)he ment chains of water molecules connected by hydrogen bonds. The question is, if the buildup of such bonds is increased by a presence of an external electrical or magnetic field or not. And if it does, how this affects the formation of drops/condensing of water vapor. - Alureiter 13:13, 3 January 2006 (UTC)
- Unless there is a source cited, I say we remove it. That reeks of pseudo-science. There is no reason that the water droplets lining up would create heavier rain, because they should line up in a horizontal manner instead of a vertical. Just use the right hand rule on the current that comprises the lightning bolt, and you'll see that the magnetic field will be curled around it. Also the effect would be very localized even if there was one. The magnetic flux decreases with R^2. --Ignignot 15:54, 12 October 2005 (UTC)
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- Yes it looks like bunk. And doesn't a magnetic field decrease with R^3?--Deglr6328 17:23, 12 October 2005 (UTC)
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- Well I might be a little rusty on my physics, but i think that since lightning is like a very long rod, it decreases with R^2 unless you are near the ends. Could be wrong. --Ignignot 19:22, 12 October 2005 (UTC)
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- According to Ampère's Law, the integral of the magnetic field around a closed path is given by the electric current flowing through a surface bounded by that path. Take an infinitely long straight wire carrying current I, and draw a circle around it with radius R. Breaking out the calculus notation,
- By symmetry, the magnetic field can only depend upon the radial distance from the wire. Ergo, the magnetic field is the same at all points on the circle of integration. Because is always parallel to the infinitesimal segment of circle , the dot product just gives the product of the two vectors' magnitudes, and we can solve the integral easily:
- 2πRB = μ0I,
- or, solving for the magnetic field,
- The magnitude of the field at any point is proportional to the current in the wire and inversely proportional to the radial distance. The field lines run in circles around the wire, with their direction given by the right-hand rule. Assuming, with first-order handwaving, that lightning can be modeled as a long straight line of current, this is the first-order result that would apply. Near the ends of the lightning bolt, of course, the field drops off faster and the infinite straight-line idealization doesn't apply. Because lighting is a transient current, there is a limit to how well magnetostatics can describe the situation, too.
- But in any case, the assertion about "heavy rain" is bunk, and I took it out. Anville 10:02, 14 October 2005 (UTC)
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"The EMP created by a nearby lightining strike can cause cardiac arrest. This happens only when the heart is at its lowest electrical charge (the very lowest point that would be recorded in an EKG right before the heart recharges for its next beat) when the ligtning strikes. Due to the percision timing of this type of event, it is a rare (but documented) occurance."
Is there really any truth in this? For one thing, the heart does not have such a "lowest electrical charge".--Paul C 09:13, 3 January 2006 (UTC)
[edit] Is disclaimer necessary?
I thought disclaimers were strongly discouraged? See Wikipedia:No disclaimer templates (a guideline). I think this would be covered by Wikipedia:Risk disclaimer. --pfctdayelise 13:55, 6 December 2005 (UTC)
- I agree, it should be removed. Bergsten 15:13, 6 December 2005 (UTC)
[edit] Electricity in lightnings
The electricity in a thunder storm is generated by piezoelectric effects in the small freezing droplets while they are elevated 10-12 km in the center of the cloud. The pressure in the crystal shell can be substantial due to the smallness of the droplets, probably exceeding 1000 bar. The piezoelectric theory completely answers all the questions on how electricity is distributed, cloud-to-cloud lightnings and cloud-to-ground lightnings.
The predominating "colliding theory" has many weaknesses, but the most obvious one is that colliding contradicts other laws of nature and it never has been observed!
John Larsson (jl[at]ing.dk)
- References please. --Heron 19:12, 1 January 2006 (UTC)
[edit] Electricity in lightnings
To "Heron"!
I haven't published any paper yet, if that is what you are looking for. Basicly, the theory is not much longer than presented here and any critical points are welcome. I have been working with lightnings theoretically for many years. I will probably have a paper published in the near future on ball lightnings with an overseas group of scientists - I'm living in Denmark. This is based on my own observations. A paper on the piezoelectric theory might follow with this group, but experimental work in this field is expensive. Suggestions are welcome!
John Larsson, Birkerød, Denmark (jl[at]ing.dk)
- Thank you John. I asked you for references because Wikipedia has an official policy not to publish original research. Whilst many of us may be interested in your theory, Wikipedia is not the place for it. --Heron 20:48, 3 January 2006 (UTC)
- Thank you "Heron"! Well, I admit dictionary editing is far from my line of living; I appreciate your policy. As for your verifiability requirement, I could perhaps wonder "Who did actually verify the "colliding theory"?
[edit] 'Fossil' Lightning
Someone should say about fossil lightning, like there's this one at the science museum in Minnesota, where there's this lightning that hit some sand and the sand turned to glass or silicon or something in the shape of lightning. I think that is cool and I want to learn more about it. 64.198.112.210 20:33, 25 January 2006 (UTC)
- Look under "Facts and trivia" in this article, or see fulgurite. --Heron 21:18, 25 January 2006 (UTC)
[edit] Triggered Lightning
I saw on TV news that some researchers had shown that the triggering of lightning has a co-relation with cosmic ray activity. i.e. other than atmospheric factors, influences from outter space can fire a nightning bolt. I guess the phenomonon is easily measured by the astronauts in orbit. Perhaps Thor is really up there. :-)
- See the "how lightning is formed" section (near the bottom of the section). This is the essence of the "runaway breakdown" theory of lightning creation. – Wisq 21:19, 26 January 2006 (UTC)
Another piece of video footage shows that by shooting a high power laser beam into the thunder head, the beam can trigger a lightning strike when it ionizes the air and creates a path for the lightning. In older techniques, tethered rocket is shot into the cloud where the metal tether acts as a conduit.
Given that lightning can be triggered on demand, is there any research on how to harvest the energy? Simplistically speaking, a power generator can be a huge capacitor, a lightning rod and a laser next to it. When a thunderhead is in the neighborhood, aim the laser at the cloud, the lightning strikes the generator and the charge is drained off slowly from the capacitor into the power grid. Repeat when ready for the next round. Kowloonese 18:57, 26 January 2006 (UTC)
[edit] feet -> metres
I changed feet to metres, as metres are used in most countries, and most of this article uses metres, so I thought having 100 million feet per second was a bit inconsistant. bruce89 22:05, 7 May 2006 (UTC)
[edit] Notice Anything Sloppy...
in the section "Types of Lightning"? --72.224.150.233 17:19, 19 May 2006 (UTC)
- If you notice something wrong, fix it. Average Earthman 17:52, 19 May 2006 (UTC)
[edit] Lightning fact citation found!
I was looking on noaa's site, and i was able to find the fact that states: "You’re An Average Person, In An Average Location, With Average Outside Activities, And Average Lightning Safety Behavior. That’s About 35,000-To-One Over A life Time, And About 3,000-To-One Of Being Seriously Affected By A Family Member Or Friend Being Killed By Lightning." from [6]
However, this is not what our article states. Here, we say "The odds of an average person living in the USA being struck by lightning once in his lifetime has been estimated to be 1:3000(NOAA, National Weather Service)." Not quite true. The odds "A Family Member Or Friend Being Killed By Lightning" are 1:3000. Odds of you(perhaps "you" must be American?) getting struck in a lifetime are 1:280,000.
I will be making the necessary changes and removing the "citation needed" tag.
[edit] Restored stripped sections
I noticed that three sections had been stripped from the article, and have since restored them. Hwever, the article IS getting a bit long... any thoughts on how to condense or split? Or is reducing its size even necessary? Bert 15:34, 27 May 2006 (UTC)
- my idea below should work if you wanna condense it a bit. Joeyramoney 16:13, 6 June 2006 (UTC)
[edit] upper atmosphere lightning needs split and expanded
i was quite surprised that these didn't have their own page. a picture would be nice. Joeyramoney 01:21, 6 June 2006 (UTC)
- Could it be done like ball lightning, ie. Main article: Ball lightning
- then small paragraph underneath with the seperate article expanded? raptor 2/7/06
[edit] Removed pending verification
In fact, the sheer number of lightning strikes from one cloud during very high lightning activity in the central states does not support the accepted theory that the charge is caused by above-described polarisation mechanism while the ice crystals and rain droplets are moving up and down in the cloud. The charge supply must be larger, probably through the ionospheric charge just described.
To spontaneously ionise air and conduct electricity across it, an electric field of field strength of approximately 2500 kilovolts per metre is required. However, measurements inside storm clouds to date have failed to locate fields this strong, with typical fields being between 100 and 400 kilovolts per metre. While there remains a possibility that researchers are failing to encounter the small high-strength regions of the large clouds, the odds of this are diminishing as further measurements continue to fall short.
During the eighties, flight tests showed that aircraft can trigger a stepped leader]] when crossing charged cloud areas. Most scientists now think that positive and negative lightning in a cloud are actually bipolar lightning.
The presence of these high-energy events support the "runaway breakdown" theory, and were discovered through the examination of rocket-triggered lightning, and from satellite monitoring of natural lightning.
It has been recently revealed that some lightning emits an intense burst of X-rays and/or gamma-rays which seem to be produced during the stepped-leader and dart-leader phases just before the stroke becomes visible. The X-ray bursts typically have a total duration of less than 100 microseconds and have energies extending up to nearly a few hundred keV.
NASA's RHESSI satellite reports tha 50 of these lightning-associated gamma-ray events per day would be detectable from space, representing about 15 out of every million lightning strikes that occur, and some of these are strong enough to fit the theory. Additionally, low-frequency radio emissions detected at ground level can detect lightning bolts from upwards of 4000 km away; combining these with gamma-ray burst events detected from above show overlapping positions and timing.
There are problems with the "runaway breakdown" theory, however. While there seems to be a strong correlation between gamma-ray events and lightning, there are insufficient events detected to account for the amount of lightning occurring across the planet. Another issue is the amount of energy the theory states is required to initiate the breakdown, and the sheer number of strikes observed from one cloud during high lightning activity. Cosmic rays of sufficient energy strike the atmosphere on average only once per 50 seconds per square kilometre. Measured X-ray burst intensity also falls short, with results indicating particle energy 1/20th of the theory's value.
-this needs a reference before it can be returned to the article. Dan100 (Talk) 11:04, 7 June 2006 (UTC)
[edit] Duke University research
The How it is formed section contains a poorly paraphrased version of this NASA article . PrometheusX303 20:15, 1 July 2006 (UTC)
[edit] Gamma ray classification
Under the subject of "HOW IT IS FORMED" The statement "Emissions of gamma rays, the most energetic form of light,..." is vaguely correct by the definition of light however, lacks technical accuracy. The portion containing "the most energetic form of light" could be removed and a hotlink inserted on "gamma rays" or insert "the most energetic form of electromagnetic emission" instead. I'm new here and I don't wand to mess up someone elses work by editing the main article without obtaining a second professional opinion.
--Lewisjr 01:27, 5 July 2006 (UTC)LewisJR
[edit] Occurrences
In what places does lightning most commonly occur, i.e. which countries have the highest thunderstorm frequencies? Is it true that in some places in Eastern Europe like Romania and in Georgia or in the Caucausus region lightning is an almost daily occurrence during the summer seasons? 62.249.242.232 14:31, 5 July 2006 (UTC)
According to this page: http://app.nea.gov.sg/cms/htdocs/article.asp?pid=1203 , Singapore has the highest incidence of lightning strikes in the world.
[edit] About the Eiffel tower picture
The caption of the picture claims that a lightning strikes the tower. Isn't it obvious that this is not the case? It is a ground-to-cloud stroke that is actually eminating from the tower. I think it's obvious at the first glance.
Also, wouldn't it be linguistically more proper to use the noun "stroke" rather than the common speech "strike"? --194.251.240.117 18:57, 10 July 2006 (UTC)
I think your wrong on that one. It's clearly striking the tip of the tower. --71.195.245.28 17:38, 28 July 2006 (UTC)
- No. If it is ground to cloud lightning, then it begins from the tower. As such, it cannot be striking it. PrometheusX303 02:59, 29 July 2006 (UTC)
- Well then why not rename the caption to The Eiffel-tower strikes the lightning to correct this obvious misnomer which is evident at first glance? Albester 21:38, 19 August 2006 (UTC)
-
-
- Because the tower didn't strike anything. PrometheusX303 22:02, 19 August 2006 (UTC)
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[edit] Lightning Strikes Safety In Pool
There is no source for pools keeping you safe from lightning strikes. The sources i have found say that pools are not a safe place to be for lightning strikes. Is there are truth to that? —The preceding unsigned comment was added by Phoenix316 (talk • contribs).
- That is false. Water conducts electricity, plain and simple. I have removed the text, but the paragraph still needs some reworking (such as the cop-out use of "etc.", which, to me, says the author can't be bothered with coming up with anything else.) —Twigboy 16:21, 9 August 2006 (UTC)
[edit] Sprites, elves, jets, and other upper atmospheric lightning
Re: It has been suggested that this article be split into multiple articles accessible from a disambiguation page. (Discuss)
- I can see no reason to do this. Disambiguation pages for Sprite, Elf and Jet already point to this article. 80.42.44.195 14:18, 14 August 2006 (UTC)
[edit] Released energy
Is it possibel that all the energy released in lightning comes from the water (in the clouds) itself? According the research, there are some energy in the water that can be released by exposing it to energy, and the energy released is higher than what is used to release it. It that's the case, maybe it could have some effect on the lightening? Some quotes and links:
"The sonoluminescent phenomena is probably related to some hitherto unknwon water bond issues. Graneau and myself feel all these processes involves the release of solar energy trapped in the water molecule's bond energy."
Cold Fog Discovery
Many other systems exist today, in a research, development, or theoretical stage, which also convert potential energy into useful work. The first example is the "Cold Fog" invention of Dr. Peter Graneau from Northeastern University that converts chemical bond energy into kinetic energy. Intermolecular bond energy in water is an available amount of energy estimated at 2.3 kJ/g. When injected with a high voltage capacitor discharge of 39.8 Joules, normal rainwater is accelerated into a cold fog that loses about 31.2 Joules of low-grade heat and a comparable amount (29.2 Joules) in fog kinetic energy output. As reported in the Journal of Plasma Physics, the output energy thus exceeds the input energy by about 100% creating a 2-to-1 overunity condition favorable for reduction to a motorized conversion system.
http://www.21stcenturyradio.com/fut...ch-11.24.00.htm
Shock waves and steam heat
http://www.alternativescience.com/over-unity.htm
193.217.195.164 00:18, 21 August 2006 (UTC)
[edit] Lighting Originates on the Ground, etc.
you know. Today in Madison, we had a pretty big lightning storm, and a number of people brought up the "fact" that "although lighning appears to come downward, it's actually going upwards." I don't know enough about this topic, in general, to call this a myth, misunderstanding, or an obscure truth, but I've heard it enough to: 1) wonder about the veracity of this statement and 2) wonder if it should be addressed more positively in this article (maybe in trivia?). Any thoughts or can someone just tell me why this is "common" knowledge? thanks in advance Madmaxmarchhare 17:28, 25 August 2006 (UTC)
- Sounds to me like a misunderstanding of the descent of the leader, versus the ascent of the return stroke. But first you have to realize that there are three distinct kinds of "motion" involved here.
- One is the physical flow of charges, and in ionized gas there are both the positive ions moving in one direction and the negative electrons moving in the other direction.
- A second type of motion is the sequential conversion of air into plasma, as when a lightning leader becomes longer. The motion of the tip of the leader has little to do with the motion of electric charges in a current. Instead, air molecules near the tip of the leader are disrupted and turned into plasma... making the leader grow longer. They're distrupted by strong e-fields, by electron avalanche effect, and by ionizing radiation emitted by atoms in the plasma. Analogy: a forest fire moves quickly, but no trees have to uproot themselves and move along.
- A third type of motion is the sequential brightening of the parts of a lightning leader during the "return stroke." As above, there is no motion involved. Instead a huge electric current is growing within the conductive plasma after the initial leader connects with the Earth. But current in a conductor cannot all begin at the same time, so instead the highest current first appears at the contact point between Earth and leader. The EM fields surrounding the conductive channel are changing at the speed of light, and as time goes on, more and more of the channel experiences the enormous current. This can be seen as a region of brightening which races outwards from the contact point, moving upwards from the ground. --Wjbeaty 00:00, 30 August 2006 (UTC)
-
- So is it this last point the reason why people claim that lightning goes "upwards?" Is the third motion the only time the actual lightning can be "Seen?" Madmaxmarchhare 17:48, 27 September 2006 (UTC)
[edit] References/Notes?
Sorry, for some reason I was tryingto add two references by a reference tag, and it's always worked before, but for some reason it was inserting two copies of the same reference. So I tried splitting them into separate reference tags. Then it was creating 4 references in stead of 2. So, I don't know what was going on. I hope I didn't bugger anything up. Maybe someone can look at the recent edit logs and point out what, if anything I did wrong?? Anyway, I've taken them out as reference tags and inserted them as External Links, which seems to work. Basically they were just in reference to some statements about Stepped LEaders and Dart Leaders. I think moderately handy mini-definitions and other info. Like I said, I hope I didn't bugger anything up. IF I did, and someone could fix it, I'd be thankful. Really no clue why it was doubling up the references into two copies instead of only 1. Initially it was showing a reference number of 2. But then in the reference section it was showing an entry 1 and an entry two that were identical. I don't know if this was a bug or what. Then when I split it, it was showing entries 3 and 4 in the article, but entries, 1,2,3,4 in the references section. Very odd... Probably, I used some wrong character or inadvertently missed a close bracket or something dumb, and it freaked out. What ever it was, I couldn't find it, maybe someone else will have more luck. But it does seem to work in the external links section in both cases, and I copied it verbatim. So, I don't THINK that's it, but I'm not sure. Mgmirkin 08:24, 29 August 2006 (UTC)
- I've reported this issue on the error reporting site, they'rel ooking into it and should have the duplicating references issue fixed shortly, I hope.
- On another note, I've added a { { fact } } tag to the statement "The first process in the generation of lightning is the ejection of charged particles from the sun in what is called the solar wind" in the How it Forms section. Not because I dispute it, but because I'd love to see some refereed articles or other reputable laymen souces in support of this noted, so I can read up. I think this is accurate, but would like to see references for it. Thx. Mgmirkin 17:18, 30 August 2006 (UTC)
[edit] (near) Infra-red pre-strike?
There's two papers, all behind logins, dealing with infrared and near-infrared emissions of lightning. Does anybody know any more about this or a source? I have a bit of video from lightning a few days back (2006/Sep/28) and one frame shows a bolt of lightning, and fainter, reddish, imprint of another bolt of lightning; I thought it was just a flare at first but the fainter imprint does not match the bolt of lightning in that frame - it does, however, fit perfectly the bolt of lightning that occurs 3-4 frames later (at 25fps, that's around 100ms). If anybody needs this material I can certainly make it available. ZeBoxx 22:02, 30 September 2006 (UTC)
[edit] The vehicle myth
Article says:
- "A better location would be inside a vehicle (a crude type of Faraday cage)."
While reality can easily tell this. The story was recently reported in Swedish news and the unfortunate woman and her friend temporarily lost hearing from the bang alone, and was believed to be only centimeters from even worse dangers. A vehicle is a bad location because: petrol tanks have been known to explode, the wind shield has been known to shatter, many parts of the vehicle can become conductive, like the gears, and electrical failures have been known to occur, all of these even individually having the possibility of being fatal in case the person is driving at a reasonably high speed.
There may be truth in the Faraday cage behavior, but there are more things to consider when talking vehicles, and I believe people reading this article won't assume the vehicle spoken of is immobile and in a garage or another place like this. -- Northgrove 09:15, 2 October 2006 (UTC)
- Yes, but more people are struck in homes or other type of shelter than in cars, I'm pretty sure. Would have to find a source to back that, but lightning casualties inside vehicles are very rare. -Runningonbrains 23:00, 2 October 2006 (UTC)
[edit] GA Review
After having a look at the article, I didn't pass it. There were several things that struck me when looking at it in depth:
- Well written: there were several issues of redundancy in the article. For example, the method through which negative lightning "descends" from the cloud is described in detail twice; I'll leave some comments inline in the text to clarify other points.
- Factually accurate: Citation of sources within the article is haphazard, and the few inline cites are not formatted consistently. In particular, all direct quotes should have an inline citation adjacent to them, to make them easier to verify.
- Broad in coverage: It passes, but it dwelves unnecessarily into trivia. You may also want to remove the "Lightning safety" section to its own article, as it is somewhat unrelated to the physics of lightning.
- Stable: Passes.
- Images: There's images of lightning in the article to the point where they become overkill. Captions that say "lightning" (which occur twice) are not particularily helpful. You don't need Image:Lightnings sequence 1.jpg if you are using Image:Lightnings sequence 2 animation.gif.
Overall, at points, it feels like several articles were merged into one, and the transitions are not fully fleshed out; as a result, I'm reluctant to give it GA status. Titoxd(?!?) 01:39, 16 October 2006 (UTC)
- I saw this after Titoxd reviewed this last night, and I have to say from my experience in WPTC - I'd be leery about this article as B-Class. This is "Lightning" not "Science of lightning". The scientific aspects of lightning are generally well covered, but there is some rather obvious stuff lacking. There is not a link to Thunder, young schoolchildren are familiar with the concept of "Thunder and Lightning", they go hand in hand. There really out to be an explanation of their connection. Also the focus is wrong in my opinion. The science is well covered, the history of research is covered, the various types are covered. The geographical distribution is not covered and the actual formation of lightning in a thunderstorm (what circumstances lead to it) is not covered. Maybe thats a topic for thunderstorm, but it should be mentioned in passing here. The effects of lightning are not mentioned: surely the fact strikes cause forest fires is significant? Also the cultural side of things is not mentioned at all. Lightning is a significant thing in mythology in general and is historically significant too. That facts and trivia section is poor in content, in terms of its scope it should be more than half of the article, as it covers everything that isn't scientific.
- Also, I'd raise a fairly strong criticism of the image selection. The place for a gallery of images is Commons, which is linked to. The purpose of the images here is to illustrate the article, a dozen pictures of lightning are repetitive and not very illuminating. The Commons gallery contains a picture of lightning near an eruption, a sprite, a old picture of ball lightning, a very useful map and so on. One specific section I'd say is particularly poor is "Lightning throughout the Solar System". Cassini hardly passed Venus recently. One of its scientific missions is to detect Saturnian lightning... Very good coverage of the scientific stuff, but the other aspects need to be covered before FAC ;)--Nilfanion (talk) 16:18, 17 October 2006 (UTC)
[edit] I Would Like to Revamp the "How it is Formed" Section of The Article
This section of the lightning article seems very shallow in its explanation of thunderstorm charge separation. I would like to totally gut it, and add my findings to the page. I have been doing book and Internet research on this subject for 12 years. Any objections or suggestions?
Kq6up 01:13, 30 October 2006 (UTC)
[edit] Added more information to the "Rocket Lightning" section
Added another few sentences to "Rocket Lightning", as the previous text was inadequate in size. The section now has more of a scientific face to it.
NiM 20:29, 02 November 2006 (UTC)
[edit] Tag about wikifying article
I looked through the article and it looked like everything seemed to be in the wikipedia format. I want to know what it is that needs to be "wikified" and I'll do it. Nathan Wonnacott 01:10, 29 November 2006 (UTC)
I can't see anything wrong with it either. Unless someone points out what needs wikifying I'll just remove the tag. Galanskov 10:01, 3 December 2006 (UTC)