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A great lightning pic from Texas

  1. May 12, 2004 #1

    Ivan Seeking

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  2. jcsd
  3. May 12, 2004 #2

    Monique

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    How about the following I once found on photo.net, the formation is called a mothership and this was shot in Australia, probably a moment before a tornado touched down..
    [​IMG]
     
  4. May 12, 2004 #3
    Speaking of lightning, I looked up the cause of thunder for another thread, and found out that the conventional explanation of the expansion of superheated air is in dispute:

    "J. Phys. D: Appl. Phys. 22 (14 August 1989) 1083-1094
    The cause of thunder
    P Graneau
    Center for Electromag. Res., Northeastern Univ., Boston, MA, USA
    Abstract. The cause of thunder is one of the oldest riddles of recorded scientific speculation. Three centuries BC Aristotle published the first thunder theory. Many other theories were proposed until at the beginning of the present century a consensus evolved which assumed thunder must begin with a shockwave in air due to the sudden thermal expansion of the plasma in the lightning channel. The only experimental support for this theory came from spectroscopic temperature determinations up to 36000 K. Any one of the assumptions made in equating 'optical' to thermodynamic temperatures can be challenged and some have been disputed. Experiments with short atmospheric arcs of lightning strength revealed average arc pressures in excess of 400 atm and peak pressures approaching 1000 atm. These results demand much higher temperatures than those found by lightning spectroscopy. Furthermore, when the strength of the short arc explosions was plotted against the action integral of the current pulse it followed an electrodynamic law rather than a heating curve. Arc photography then proved conclusively that the plasma did not expand thermally in all directions, but preferentially at right angles to the current, as if driven by organised electrodynamic action. Possible electrodynamic forces which might drive the thunder shockwave are the Lorentz pinch force, the longitudinal Ampere force and the alpha-torque force of the Ampere-Neumann electrodynamics. The pinch force was found to be far too small and in the wrong direction to be the cause of thunder. Longitudinal and alpha-torque forces act in the correct direction but, so far, quantitative agreement has not been achieved. This may have to wait for a complete Ampere MHD"

    The cause of thunder
    Address:http://www.iop.org/EJ/abstract/0022-3727/22/8/012/
     
  5. May 12, 2004 #4

    Ivan Seeking

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    Not nearly so dramatic as Monique's pic, these unusual clouds were seen just before some tornadic activity in the Midwestern US.

    [​IMG]
    [​IMG]

    Again, from coasttocoastam.com

    http://www.coasttocoastam.com/gen/page139.html
     
    Last edited: May 12, 2004
  6. May 12, 2004 #5

    Ivan Seeking

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    a couple of side notes:

    As for Zooby's post, this all relates to our other discussion about spark gaps - the evolution of lightining is also a bit of a mystery. I know I have a book that talks about this but I haven't found it yet.

    Monique, that is an awesome shot!

    Finally, Tsu and I used to hang a bit with an ER doc [Mark] who happened to have a BS in physics. Mark and I were talking about lightning one day and I pointed out that in principle, if one was to wear an appropriately constructed metal suit, a person could take direct hits by lightning will no ill effects.

    Mark wanted to try it!

    This is the same guy that threw his kids into the car and rushed over to the coast to experience some 90 mph winds. :eek:
     
    Last edited: May 12, 2004
  7. May 12, 2004 #6

    Evo

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    Now that is scary! :surprise:

    (so happy to have the old smilies back)
     
  8. May 12, 2004 #7
    I saw mammatus clouds in Minnesota once. "Mammatus" means "breast shaped".
     
  9. May 12, 2004 #8

    Tsu

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    What's with your recent 'breast' fixation, Zoob? :surprise: :biggrin:
     
  10. May 12, 2004 #9

    Math Is Hard

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    I guess Zoobies like Boobies. :biggrin:

    I loved those storm pics. I was just back in Houston a few weeks ago and I got to experience some of the magnificent thunder and lightening storms that I have missed living out here in So. Cal for the last 10 years.
     
  11. May 13, 2004 #10
    Last edited: May 13, 2004
  12. May 13, 2004 #11

    Ivan Seeking

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    ...similar in their naming convention to the Altocumulus Testicularis formations.
     
  13. May 13, 2004 #12

    jimmy p

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    Meteorologists must see some weird breasts...
     
  14. May 13, 2004 #13

    Tsu

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  15. May 13, 2004 #14
  16. May 13, 2004 #15

    Tsu

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    Never mind, Zoob. Go back to sleep... :biggrin: :devil:
     
  17. Jun 9, 2004 #16

    Ivan Seeking

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  18. Jun 9, 2004 #17
    That is an awesome photo, Monique. It's like the revenuers coming to town... :biggrin:
     
  19. Jun 9, 2004 #18
    Is that photo from photo.net for real??!? :eek: If so whats the name of that formation, I would like to learn more about it.
     
  20. Jun 9, 2004 #19
    That looks terrible ! but i believe it to be a true one !
     
  21. Jun 9, 2004 #20

    Monique

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    It's called a mothership cloud formation seen during heavy storms.
     
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