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Why a mushroom cloud?
- To: "meteorite-list@meteoritecentral.com" <meteorite-list@meteoritecentral.com>
- Subject: Why a mushroom cloud?
- From: Jim Hurley <hurleyj@arachnaut.org>
- Date: Thu, 03 Jun 1999 11:58:08 -0700
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- Organization: Mind Your Own, a division of None Of Your
- Resent-Date: Thu, 3 Jun 1999 15:02:29 -0400 (EDT)
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I had always wondered why a large explosion tends to
produce a mushroom-shaped cloud.
At first, I thought it was just something to do with
nuclear explosions, but other observations seem to
indicate it is a universal phenomenon.
I think I understand how it happens:
Imagine a large explosion at ground level. To a first
approximation assume the earth is uniform in density.
In that case the explosion would generate a hemispherical
depression in the blast area.
Shock waves in the reverse direction, 'bouncing back'
from the blast will be focussed due to the hemisphere,
exactly like a lens.
This would force the ejecta and dust and gases upwards
vertically at hypersonic speed where they will rise until
slowed down by friction.
At that retardation point, the dust and gases would amass
to form the mushroom cap.
This seems reasonable to me, does anyone know if that is exactly
what happens?
--
Jim Hurley Freelance graphics artist
Web page design; graphics; multimedia
<URL: http://www.arachnaut.org/ >
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