From: SFPhysics@aol.com
Date: Fri Sep 24 1999 - 19:25:32 PDT
From: SFPhysics@aol.com Message-ID: <28bbc7bd.251d8c9c@aol.com> Date: Fri, 24 Sep 1999 22:25:32 EDT Subject: Why Lightning Hits Ground
Actually I believe the poser of the question was on target in wondering why
the electrical discharge hit the ground at all. Most lightning IS from cloud
to cloud or from charged air mass within a cloud to another charged air mass.
All that is needed is for the potential to overcome the usual, if memory
servers, 75,000 Volts per inch that air has as a dielectric insulation
strength. (dry air, don't have a clue about wet)
When lightning does go for the ground it is because the earth is such a huge
source or sink for electrons and is closer to the base of the charged cloud
than another part of the cloud with an opposite charge.
As for the opposing charges within the cloud causing the cloud to collapse or
some other effect due to unlike charges attracting, I feel that the distance
of some 35,000 feet between the base and the top of a thundercloud becomes
less relevant than the 1000 feet between the ground and the cloud base. The
earth gets it because it is closer yet we don't see the cloud reaching down
before the strike. Wonder if the rain starts after the lightning alters the
electrical balances in the cloud? Hmmmmm.......
Al Sefl
Guaranteed to be correct 50% of the time!
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