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Thread: Positive lightning

  1. #1 Positive lightning 
    Forum Professor leohopkins's Avatar
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    I have heard a lot about "Positive lightning" in the sense that it tends to do more damage to aircraft.

    My question is simple. What is it ?

    Surely it cannot be lightning with a positive charge as all electrons are negatively charged ?


    The hand of time rested on the half-hour mark, and all along that old front line of the English there came a whistling and a crying. The men of the first wave climbed up the parapets, in tumult, darkness, and the presence of death, and having done with all pleasant things, advanced across No Man's Land to begin the Battle of the Somme. - Poet John Masefield.

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  3. #2  
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    Negative lightning travels down - positive travels up - It is very much more powerful than the negative - a google should help.


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  4. #3  
    Forum Sophomore Kabooom's Avatar
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    I remember seeing a shower or something where lighting from the ground and sky meet midways, so Megabrain's answer makes sense
    WHAT?!
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  5. #4  
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    Lightning (the main strike) travels at 0.1c or thereabouts, I congratulate you on having such superb eyes!

    We think of lighning as travelling down only because it seems 'logical' that it comes from the clouds (or if you like, clear sky no lightning). This misconception is reinforced by such things as signs depicting lightning as 'squiggly arrows pointing down', cartoons etc.
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  6. #5  
    Forum Sophomore Kabooom's Avatar
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    Haha, I meant show, not shower...
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  7. #6  
    Forum Ph.D. Steve Miller's Avatar
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    What show has lightnings on the ground?

    Steve
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  8. #7  
    Universal Mind John Galt's Avatar
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    From the wikipedia article on positive lightning:
    Positive lightning makes up less than 5% of all lightning. It occurs when the leader forms at the positively charged cloud tops, with the consequence that a negatively charged streamer issues from the ground. The overall effect is a discharge of positive charges to the ground. Research carried out after the discovery of positive lightning in the 1970s showed that positive lightning bolts are typically six to ten times more powerful than negative bolts, last around ten times longer, and can strike tens of kilometres/miles from the clouds. The voltage difference for positive lightning must be considerably higher, due to the tens of thousands of additional metres/feet the strike must travel. During a positive lightning strike, huge quantities of ELF and VLF radio waves are generated.

    As a result of their greater power, positive lightning strikes are considerably more dangerous. At the present time, aircraft are not designed to withstand such strikes, since their existence was unknown at the time standards were set, and the dangers unappreciated until the destruction of a glider in 1999.


    http://en.wikipedia.org/wiki/Lightning
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