There was recently a program on PBS (Nova, I think) that reviewed current
research on lightning strikes. This research is done mainly in the state of
Florida. The potential in a typical thunder cloud was measured and found to
be much less than required to draw an arc to earth. To help explain why an
arc did subsequently occur, they brought in an expert on cosmic rays. He
made some measurements and found evidence of cosmic rays from a strike.
So now it is theorized that lightning is related to bombardment of charged
particles from cosmic rays. The potential is increased by a huge amount
when this happens. This theory also helps explain why sometimes a lightning
strike will occur without presence of a thunder cloud, but often in air that
contains large quantities of dust or other charged particles.
If this is true, a strike event is truly unpredictable unless one can
forecast when and where cosmic rays will strike a cloud.
73, Keith NM5G
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Peter Chadwick
Sent: Saturday, February 11, 2006 6:21 AM
To: garyschafer@comcast.net; 'StellarCAT'; 'tower'
Subject: Re: [TowerTalk] lightning and insulated elements..
K4FMX said:
<A grounded tower is NOT less likely to be hit by lightning.
Actually a grounded tower is a little more likely to be hit than a non
grounded one.> Somewhere, some years back, I remember seeing some University
work that suggested that the grounded tower had a discharging effect that
reduced the chance of strike in the vicinity, but when a strike did occur,
it had a higher probability of hitting the tower. Same as a lightning
conductor on a building.
Where to find the reference now is beyond me, though.....
73
Peter G3RZP
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