What is Lightning: Definition and 262 Discussions

Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily equalize themselves, causing the instantaneous release of as much as one gigajoule of energy. This discharge may produce a wide range of electromagnetic radiation, from very hot plasma created by the rapid movement of electrons, to brilliant flashes of visible light in the form of black-body radiation. Lightning causes thunder, a sound from the shock wave which develops as gases in the vicinity of the discharge experience a sudden increase in pressure. Lightning occurs commonly during thunderstorms as well as other types of energetic weather systems, but volcanic lightning can also occur during volcanic eruptions.
The three main kinds of lightning are distinguished by where they occur: either inside a single thundercloud, between two different clouds, or between a cloud and the ground. Many other observational variants are recognized, including "heat lightning", which can be seen from a great distance but not heard; dry lightning, which can cause forest fires; and ball lightning, which is rarely observed scientifically.
Humans have deified lightning for millennia. Idiomatic expressions derived from lightning, such as the English expression "bolt from the blue", are common across languages.

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  1. J

    Can a Lightning Strike Kill Someone Flying in the Sky?

    I recently watched the movie Chronicle, and in it, one character is killed when he is flying in the sky and lightning strikes him (the lightning doesn't hit the ground afterwards, if that matters). Would this actually kill someone if they weren't touching the ground when they were struck? And...
  2. A

    Lightning strike->positive streamers

    Lightning strike--->positive streamers they said the lightning will connect to a positive streamer to "complete" the circuit. When a lightning strikes a man, do human produce positive streamers?
  3. M

    Understanding Lightning Return Strokes

    Hi, I have a question about lightning return strokes. It makes sense when I think about the return stroke on its own - as in lightning from the ground to the cloud but I'm a bit confused when I think about it as a reaction towards lightning. Why does it occur? Doesn't lightning equalize the...
  4. J

    If lightning can destroy trees, how come that people survive it?

    I mean, trees are a lot bigger than people, aren't they?
  5. I

    Question about Einsten's Train and lightning experiment

    It might seem to be a stupid question..But I really want to figure it out so I posted it here. Again, the problem should be familiar to anyone here. Two lightning bolts strike at both end s of a moving train simultaneously (according to the stationary observer). My question is: In the...
  6. C

    Calculate the Distance of lightning

    Hello all, Determine a number N so that if the number of seconds (t) between flash and thunder is divided by N, the result is the distance (d) in miles. Be sure to specify the units of N. The speed of sound in air is 343 m/s. Assume the travel time of light is negligible. D = t/N So would i...
  7. M

    Lightning strikes energy question

    Lightning strikes a point on earth, delivering -20.0 C of charge from cloud to Earth across a potential difference of 1.00 * 10^8 V. How much energy is delivered to the ground? Uelec= V*q = 1.00 * 10^8 V* -20.0 = -2.0*10^9 J. But the book says it is 2.0*10^9 J... why is it positive and...
  8. Q

    What Is the Scientific Explanation for Ball Lightning?

    Literally, a ball of lightning that sustains for way longer than a 5th of a second, any good explanations?
  9. phosgene

    Who is most likely to be hit by lightning

    Homework Statement During a thunderstorm Bill and Corky are caught outside in the middle of an extremely large paddock (with no trees, houses or any structures in sight). Bill, who is extremely tall and flexible, curls up into a perfect 1 metre diameter ball. Corky who is only 1 metre tall...
  10. L

    Unusual Cloud to Cloud Lightning

    Well this is my first thread so I figured I'd start off on the right foot in the crazy forum. In all seriousness I would like to attempt to explain some experiences I've had that I have been unable to find an explanation for. I will provide as much detail as I can recall to try an aid anyone...
  11. N

    Lightning Rods: Can They Stop Thunder?

    can lightning rod prevent the sound of thunder near the area the lightning stroke?
  12. C

    Whats the acceleration of an electron in lightning?

    I found this equation a=qE/m, for finding the acceleration of an electron.[1] If I were to try to find the acceleration of an electron in lightning, what variable would pertain to that. Its just curiosity whether the unruh effect cuases a noticable tempature change in lightning...
  13. C

    Would space lightning last longer then earth lighting?

    I'm writing a paper on the possibility of harvesting space lighting, but the main question would be, does space lightning last longer then real lighting. My argument would be that air resistance cuases the channel which the current is traveling through to split. However in a vacuum, you would...
  14. S

    Lightning according to faraday's law

    Faraday's law applied to lightning, " When lightning occurs air conducts current which happens in Earth's magnetic field will it produce motion in air".
  15. L

    Is Time Travel Possible with Speed of Light?

    Hello! My dad reckons if you moved faster than the speed of light you would travel forward in time? Am I right in thinking this is ridiculous!
  16. J

    How would the intense light from a massive thunderous lightning storm

    How would the intense light from a massive thunderous lightning storm compare against regular daily sunshine in terms of the electrical current generated from a solar panel array? Just curious.
  17. J

    Is during lightning clouds losses some its mass?

    during lightning when two clouds attract each other on that time, they loss some of its mass??
  18. U

    Can a lightning take the same path multiple times?

    Hi all, I wondered if you guys could help me with this question. I have been showed a picture of a lightning. It is not the complete lightning on that picture, maybe 1-2 thirds of it. To me it looked a little blurry, so I asked if the photographer had used a tripod to make sure the camera...
  19. H

    Einstein's Train and Lightning Bolt Simultaneity Situation

    I have seemed to confuse myself after watching this video: Everything makes sense except for the bit where the video says the passenger sees the bolts at different times. How can this be justified and how do we know the passenger doesn't see them at the same time from his frame of reference?
  20. A

    Lightning Generates How Much Antimatter

    A relatively recent story about anti-matter being created by lightning caught my eye. http://www.space.com/10602-antimatter-beams-thunderstorms-nasa.html I was curious if anyone on this forum could quantify "how much" antimatter could be created by a terrestrial lightning strike...
  21. Evil Bunny

    Where does lightning want to go?

    Where does lightning "want" to go? I work on navigation equipment at airports, and we've had a few lightning storms recently... Every time there is lightning on (or near) the airport, we end up replacing circuit cards in our equipment. These are obviously not direct hits, because the damage...
  22. A

    Why hasn't lightning charged the earth?

    The Earth has been struck by lightning for 4.5 billion years.Then why is it that the Earth has acquired no [or negligible] charge. I Have also heard that their is a permanent potential difference between the Earth's atmosphere and surface.What is the cause of this?Why doesn't lightning...
  23. Jim Kata

    Can Lightning Strike on a Car Kill You?

    If lightning strikes your car, would it kill you? I understand that you are in a Faraday cage so you are protected from being electrocuted, but would the sheer heat cook you?
  24. A

    Is there any possibility that the high voltages needed for lightning

    Is there any possibility that the high voltages needed for lightning come from the thunderclouds assuming some characteristics of a crystal. In the same way a PZT is able to generate enough voltage for a spark.
  25. R

    Lightning & Voltage Spikes: Exploring the Effects

    How does lightning cause a voltage spike? Is it the changing magnetic field caused by the lightning current that induces an emf in the power lines, or are electric charges deposited on the actual lines (like a battery pushing charges). Is it possible for the emf of the lightning to cancel the...
  26. Darken-Sol

    Harnessing the Energy of Lightning: An Endless Source of Power?

    why can't we harness the energy in lightning? it seems to be an unending supply of electricity.
  27. Spinnor

    Should metal chimney liners be grounded against lightning strikes?

    I was at a home today which a while back had a lightning bolt strike the chimney and explode the top of the chimney off. On the drive home I got to thinking, I have two metal chimney liners, one for a first floor wood-stove and another for the furnace and only the furnace liner is indirectly...
  28. A

    Lightning Rod Tip Radii: Why So Small?

    greetings, why the radii of the tip of lightning rod is small(few mm)? thanks.
  29. B

    How Is Capacitance Calculated in a Cloud-to-Ground Model?

    1. The base of a cloud has an area of 2*10^7 metres squared and is on average 1km above the ground. treating the base of the cloud, the ground and the intervening air gap as a parallel plate capacitor, calculate the capacitance.[relative permittivity of air = 1.0] 2. I tried to say C...
  30. S

    Lightning bolt charge physics problem

    Homework Statement A lightning bolt carrying 30,000 A lasts for 50 microseconds. If the lightning strikes an airplane flying at 20,000 ft, what is the charge deposited on the plane? Homework Equations q(t) = \int i(x)dx The Attempt at a Solution So, using the equation above I...
  31. U

    Cause of Lightning: What is the Real Explanation?

    First apologies for asking what is in all probability a misconceived question, but here goes. The accounts of the cause of lightning seems to explain it in terms of turbulence in high clouds causing ice particles to become electrically charged by bumping into each other. But this seems...
  32. J

    Ethernet cable attracting lightning

    I ran about 200 ft of ethernet cable around the back of my house from my computer room to my bedroom, to stream netflicks. I tried wireless but I got tired of constant signal lossl and movie break-ups, hence the reason for direct wiring . The cable is run in 3/4 grey pvc buried about 5 to 6...
  33. A

    Cause of Lightning - Understand How It Happens

    Lightning is quite a common phenomena and yet i don't have a clear understanding of how it is caused. Can someone tell me the real cause of lightning?
  34. A

    Exploring the Science of Ball Lightning

    What is ball lightning and what is the science behind it?
  35. L

    Electricity & Its Properties: Exploring Valence Electrons & Lightning

    I am researching electric and magnetic fields, and so far from my understanding each electron produces its own electric field, negatively charged, and thus the atom has its own electric field, am I right so far? Some atoms have better current than others, this is related to the number of valence...
  36. M

    Exploring Electric Potential of Lightning Clouds

    Opposite charges are built up between lightning clouds and the earth, which creates a potential, which causes lightening. Say you had a voltmeter that could handle infinite current and with leads hudnreds of meters long, and you stuck one lead onto a cloud which is about to create lightning...
  37. M

    Calculating Capacitance and Charge for Lightning Formation

    [b]1. As a crude model for lightning, consider the ground to be one plate of a parallel-plate capacitor and a cloud at an altitude of 520 m to be the other plate. Assume the surface area of the cloud to be the same as the area of a square that is 0.30 km on a side. a) What is the capacitance...
  38. W

    What happens when lightning strikes the earth?

    What happens when lightning strikes the earth? This is my first question. Another question is that "Why do not we get a shock when in an overload,earthing comes into play?" I should explain my 2nd question::: I mean to say that when a short circuit or overloading takes place excess current...
  39. H

    Car Struck by Lightning: Faraday Cage or Skin Effect?

    Most places I've read say it's because the car forms a Faraday cage, but a few say that is incorrect and that it's actually from the skin effect. The notable case of the latter explanation is from the Boston Museum of Science: http://www.mos.org/sln/toe/cage.html This guy, Dr. Davis from the...
  40. P

    Ball lightning = magn. induced phosphenes?

    A recent explanation for "the majority of ball lightning observations": Is this plausible? A way to debunk this would be to find credible ball lightning videos(maybe on youtube), but i don't know if there are any.
  41. G

    Special relativity: Lightning and Trains (no math involved)

    Homework Statement Consider the relativity of simultaneity: A student in a train at rest from his point of view and a professor in a train that is moving in the positive x direction from the student’s perspective. Two lightning of different colors will strike at opposite ends of the trains...
  42. Ivan Seeking

    Lightning Strike or Fake? Investigating a Viral Video

    Does this add up? On one hand, the dog seems to react as if nearly hit by lightning. It looks to me like he leaps, or makes an odd move, just after the lightning is seen. What bothers me is the delay for the sound. It seems to me that we have something close to a half-second delay, when the...
  43. N

    How Does Lightning Affect ADSL Router?

    How does the lightning affect or damage the ADSL router? because the internet conection is a telephone line(wire)? we connect the telephone line to get the internet connection after activating the ADSL connection, so how lightning can affect or damage the router when it is connected? what...
  44. T

    Generating and storing electricity for lightning in a lab

    Hello, I'm designing an experiment that requires a short pulse of electricity at voltages above and beyond 10,000,000 volts at about 300A. I'm having a hard time finding devices that can produce that high of a voltage and current without breaking down, much less finding a way to store that much...
  45. M

    Cassini Captures First Ever Video Of Lightning On Another Planet

    Not sure if this has already been posted on the board, but here is another fascinating bit of information collected by the Cassini spacecraft as it floated near Saturn. Check the link below for pictures & the video...
  46. T

    Mobile phone user hit by lightning

    Hey, is this really possible? If yes then should I avoid using mobile phones outside or even in-car? Seems to me that there should be some danger signs on phones then... Mobile phones=potential killers?
  47. P

    What Causes Lightning Rods to Buzz?

    I am familiar with the basic theory of how lightning rods work, at least as explained in the text "Electromagnetics" by Kraus (Ohio State). I was once standing on the roof of a 14-story dormitory at the U. of Illinois, Champaign-Urbana. A thunderstorm was approaching. The lightning rods...
  48. C

    Lightning + static electricity + moisture = confusion

    I've never understood this, but none of the people that I thought would know could think of a reason, either. It's probably just some simple detail that I've overlooked, but I'm stumped. So... I've always been taught that "lightning is a gigantic spark of static electricity", but I've also...
  49. C

    In a typical lightning strike, 2.5 C flows from cloud to ground in 0.20 ms.

    Homework Statement In a typical lightning strike, 2.5 c flows from cloud to ground in 0.20 ms. What is the current during the strike? Homework Equations I = Q/t The Attempt at a Solution The reason I keep getting this wrong is because it says I am rounding something off wrong. I...
  50. N

    How much water is ionized in the lightning?

    If each water molecule donates one electron, how much water is ionized in the lightning? One mole of water has a mass of 18.1 g/mol. Answer in units of g. Avogadro’s number is 6.02214e23 /mol. ok so this is what i did... (18.1grams/1mole)(1mol/6.02214e23 molecules)=3.005576e-23...
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