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

[MexicoDoug at aol.com]

En un mensaje con fecha 07/09/2004 3:27:30 PM Mexico Daylight Time, 
marco.langbroek at wanadoo.nl escribe:

> In the case of meteors during their visible meteor phase, you
> are talking of speeds at least tenfold that, and often (quite a lot) more.
> Even the slowest meteor has an initial speed of at least 11.2 km/s, and, in
> the case of surviving meteorites, extinguishes with speeds between 3 to 7
> km/s, and the latter speed values are reached only in the latest part of
> 

Hola Marco, those are some very impressive statistics you present.  You are 
right when you say that we are comparing apples to pears in the case of Space 
Shuttle Reentry and iron containing bolides.  I made that clear, too, when I 
brought it up: rather than compare I suggested just some consideration (which 
has some, non-zero worth, in my opinion) as we focused a little more on the low 
end of the energy spectrum.  You discuss initial speeds of 11.2 km/s going as 
low as 3 km/s at the ending of the pathways. For comparison, the Columbia 
tragedy happened at 5.6 km/s, exactly half the initial speed you have quoted and 
the normal navigation I mentioned happens at about twice the minimum you 
mentioned - both within the range you accept for the "ending of the path".  

In the tragedy, I am not ready to believe wind current is the only culprit of 
scattering, and plenty of fragments did survive the macro "disintegration" 
over an area I bet as large as France - at an altitude of the diameter of Paris 
(Just speaking of order of magnitude loosely here, I don't remember the 
"width" of the ellipse) Would you really expect the tiles traveling in the meteoroid 
range of speeds that fell over near California to have followed smooth 
arcs...and is that so bad an example as not worth considering?

I am still confused on one point, and that is: Of the over 1000 photo's 
you've mentioned, none of which I have had a pleasure to see, not a single one was 
recovered, according to your comments.  Is it possible you and I are 
discussing apples and oranges?  You do mention that some are expected to have produced 
meteorites.  But that is a conjecture ...I do not dispute your frequencies you 
imply, as I am not sure if the supposed slower speeds at the end of the 
incandescent train can be I wonder, for example, if the Allende meteor(ite) 
appeared to zigzag.  It heavily sloughed (fragmented) and probably did not go out in 
a single explosion I believe.  Some pieces have primary fusion crust, others 
secondary, others tertiary, and others none.  Do you really think Allende came 
in a nice arc like the meteor photos you have?

Finally, any information or graphs, or images or pdf's you might have would 
be very interesting which you use to conclude that even toward the end of the 
visible train of large probable meteorite producing bolides continue in a 
straight line/arc.  Also I would love to see some graphs relating mass, velocity, 
and speed for a spherical blob entering the atmosphere at interesting angles, 
to see its velocity profile vs. time, assuming a perfectly baked 
(brazed...etc.) fusion crust at landing.  That could help look for the limits for which 
zigzagging might occur, if it does at all.

Thanks for your kind thoughts,  also, still wondering if you really believe 
in the objections for Pasamonte (motion, dust train only), but perhaps this is 
viewed as to little a niche topic for this group which I am grateful to 
benefit from, so I'll quit here, hoping you can address  the real data and relevancy 
question briefly.  Saludos, Doug
Doug
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