[meteorite-list] Magnetite/Glass Meteorite Balls

[Chris Peterson]

Well, without some sort of mineralogical analysis, there's no way of 
knowing what you had. There are pretty good models for the dust size 
distribution in shower debris streams. Most of it is of a size that 
won't burn at all when it encounters the Earth's atmosphere, but that 
size can't get to the ground in less than months (and can't be seen 
under a hand lens in any case). Large enough particles to drift down in 
a few hours are surely rare: the total Perseid mass that actually burns 
up is only something like 100 ug/hour/km^2. Even if none of it burned up 
there's no way you'll find a significant amount in a small pan from one 
night's activity.

Aside from that, there's no reason to think that Perseid debris should 
have any significant iron content.

I ran a dust collector for three years. It had a collection surface of 6 
m^2, and a water flushing system. The amount of dust collected varied 
widely from day to day, and was uncorrelated with meteor showers. Much 
of the dust was ferromagnetic or paramagnetic. Twice, when we had a high 
amount of material, we examined the dust with a SEM. We were unable to 
find any particles that showed signs of melting or otherwise resembled 
the meteorite dust collected at high altitude. In three years, we failed 
to conclusively identify a single micrometeorite, although we had a 
handful of spherical particles (10-100 um) that were interesting.

IMO, the dust you collected after the Perseid shower was unrelated to 
that shower. Statistically, you can't correlate two events from a single 
sample.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "Jerry Flaherty" <grf2 at verizon.net>
To: "Chris Peterson" <clp at alumni.caltech.edu>; "Meteorite List" 
<meteorite-list at meteoritecentral.com>
Sent: Friday, July 13, 2007 10:14 AM
Subject: Re: [meteorite-list] Magnetite/Glass Meteorite Balls


> Chris I beg to differ with you as personal experience during a very 
> active Persid shower in the late 80's or early 90's produced a 
> sterling[S] quantity of particles which jumped from beneath the water 
> to a magnet and lent themselves to a magnificent show under a hand 
> lens.
> Jerry Flaherty