Xref: utzoo rec.boats:4179 sci.physics:13749 sci.electronics:13088
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From: grege@gold.GVG.TEK.COM (Greg Ebert)
Newsgroups: rec.boats,sci.physics,sci.electronics
Subject: Re: St Elmo's Fire (was Re: Lightning)
Keywords: Induction, space charge, capacitance, point action
Message-ID: <1203@gold.GVG.TEK.COM>
Date: 25 Jul 90 20:31:28 GMT
References: <1990Jul18.111525.5749@ioe.lon.ac.uk> <richard.648454274@snap.la.locus.com> <kimf.648884649@arrester>
Followup-To: rec.boats
Organization: Grass Valley Group, Grass Valley, CA
Lines: 21

>>Your head and your feet have the same
>>potential as the earth.  A foot from your nose, the air is at a potential
>>of +200V.
>
>Anyway of hooking up to this potential difference and drawing some
>energy from it? :)
>

Er, um, it depends upon how determined you are. I read, perhaps in Scientific
American , that there is a current density of 1000 amps/sq mile over the 
surface of the earth, but I don't recall what the weather conditions were; I
would presume it would be during an impending electrical storm. That figures 
out to ~40uA/sq foot, unless you happen to be 'lucky' enough to snare a
lightning bolt. The same article mentioned that NASA has measured the current
of several bolts which struck launch towers to be up to 30,000 amps (OY !!).

I had an insulator from a 16KV power line which had an unusual melted spot on
the mounting flange, like someone heated it with a torch and let the molten
metal 'run' a bit. I've always wondered if it was from a lightning strike.

Has anyone ever seen lightning strike the ocean ? Must be rather trippy...