[HOE] Mushroom-clouds (OT sorta)

["" <calabim69@hotmail.com>]

I thought this was interesting so I am sending it to the list. I thought of 
some intereest was that space link. Can you say Unity.



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         Why do large explosions create mushroom-shaped clouds?

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Atomic blasts are not the only kinds of explosions that create
mushroom clouds.  Any explosion large enough will create a mushroom
cloud if it happens close enough to the ground.  What forms the
mushroom shape?

When the blast begins it is a nearly perfect sphere.  But the
spherical blast front soon encounters the ground and begins to
vaporize it.  Because of the way the blast hits the ground, it
usually creates a parabolic crater with the greatest curvature in the
deepest, central part.

Similar to the way parabolic telescope mirrors focus light, the
crater focuses the blast wave and redirects it straight up, forming
the vertical "stem" of the mushroom cloud. Eventually the stem loses
energy and flattens out against the resistance of air layers higher
in the atmosphere, forming the "cap" of the cloud.

Most people hope they never see one:
http://www.netoriginals.com/uss/bomb.html

Mushroom clouds can also happen in outer space:
http://antwrp.gsfc.nasa.gov/apod/ap990203.html

More Cool Facts about explosions:
http://features.LearningKingdom.com/fact/archive/1998/05/19.html
http://features.LearningKingdom.com/fact/archive/1998/06/12.html
http://features.LearningKingdom.com/fact/archive/1999/07/16.html

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