(meteorobs) Why do some meteors appear to zig-zag?

[MexicoDoug at aol.com]

lgramer at upstream.net    escribe:

>>I'd be interested in hearing other readers' thoughts on this topic!

>>Clear skies all,
>>Lew Gramer
>>http://www.meteorobs.org

Hola list,

http://six.pairlist.net/pipermail/meteorite-list/2004-June/142181.html

http://six.pairlist.net/pipermail/meteorite-list/2004-July/142212.html

Very interesting thoughts and most probably correct for the way you defined 
the problem.  We just went through this discussion on the meteorite-list so 
I'll post my 2 pesos here with the links.  Basically either spiral and zig-zag 
(either a true zig zag or an optical zig zag depending on observer position: see 
first link above) are very likely when meteorites are likely.  When much of 
the cosmic velocity is damped, but still is faster than free fall and creating 
smoking trails.  Whether it is a spiral or zig zag or simple parabola will 
depend on the destructive sloughing of material shaping it as it goes along.  
Perfect orientation (nosecone) most probably would form an arc.  Steam roller 
orientation happens when the axis of rotation is perpendicular to the direction 
of travel, and generally parallel to the ground, spiraling is when the axis of 
rotation is perturbed or unstable, though generally it cycles a the air shear 
shapes the rotation.  Rotation is on the order of a second or three, and this 
gentleness it acts tform a relatively continuous stress to the meteoroid, 
shedding (sloughing material), the spirals oor zigs are caused by the changes in 
cross sectional area on the ever changing, probably fragmenting body.  If it 
splits and creates too great an area change, it likely will explode...so 
depending on the fragmentation from the stress points will depend how big the main 
mass will be.

Anyway, this only applies to the special case of a soon to meteorite or 
hopeful.  I have made an extensive study with one particular one discussing it with 
witnesses, and the sounds they hear play out the theory above.  There are 
other examples where similar was observed.  Also, the first of the two postings 
above has a picture with due credit of just this sort of zig zagging.

Saludos
Doug Dawn
Mexico
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