[meteorite-list] Closure on the Lancaster, PA Event of 11-18-00

From: David Freeman <dfreeman_at_meteoritecentral.com>
Date: Thu Apr 22 09:37:33 2004
Message-ID: <3A310DCA.C10FFF2F_at_fascination.com>

Dear E. L. and List;
This post has my nomination for the most interesting and fascinating
meteorite article of the year!
It is very well written, is main stream "List" content, and has a happy
ending!
This is a gem of a story and should be recognized for the educational, and
procedural values that it possesses.
So much of the "good stuff" err..."right stuff" is taking place above 60,000
feet, in a foreign desert, or in a laboratory somewhere and is at times
difficult for the novice or common list member to mentally digest. This
quality article is brimming with fact, mystery, and method. It leaves me
with field knowledge, renewed enthusiasm, and satisfaction.
I recommend that this post be submitted one day to the meteorite joint
powers board (in lieu of an official meteorite dealers/collectors
association) for recognition of its value in promoting the science and
hobby of meteorites.
Sincerely thankful,
David W. Freeman

"E.L. Jones" wrote:

> Hello List,
>
> The short version: The impact was not meteoric but from an explosive
> device.
>
> The long version: This was a good practice for recovery of the real
> thing.
>
> BackGround:
> Before Thanksgiving Holidays there was a news report and internet email
> notice that a possible meteorite had landed on a car in Lancaster
> Pennsylvania. After many delays, we dissected the dash of the car in
> Lancaster, PA on Tuesday night which had a peculiar hole in its
> windshield. It had its windshield and dashboard disrupted
> --coincidentally-- during the Leonids shower around 3 AM (EDT) local the
> Morning of
> 18 Nov. The proximity to a fireball sighting headed vertically down
> over Lancaster and shape of the damage raised suspicion that this might
> have been a meteorite impact. Initial inspection via various local
> Police and Fire personnel failed to determine a positive identification
> to the
> cause. Being local to the area and having the most interest, it seems,
> I was invited to participate in the search.
>
> Search:
> I joined the car owner, his family , and local planetarium personnel to
> see if we could determine the cause of the damage. An external and
> internal scan did not produce any large pieces of foreign material. I
> conducted a scan with a magnifier over a portion of the windshield took
> some samples of several magnetically attractive, dark shards. I looked
> at them under my stereo microscope and they appeared to be shards of
> tar/pitch -which has a glass-like, conchoidal fracture. The dash cover
> had been removed, it too, showed no clearly meteoritic fragments.
>
> Not finding anything meteoritic we moved to the inside. The car's
> windshield and dashboard had been penetrated by an approximately 75-90°
> down-angled force. A magnet probe into the well yielded nothing and
> hopes of finding a meteorite were fading, if not confounding-- there
> were no clear clues either way. Striations on the chrome trim but not
> on the windshield were suspicious and later would be a contrasting clue.
>
> After enlarging the opening in the dash to gain access into the baffles
> of the heater core housing, we located what appeared to be a crust-less
> fragment of a bluish-gray material with tiny protruding
> "chondrule-sized" bumps-- not unlike the Zag specimens I had brought
> along for making
> field comparisons. The brief moment of suppressed excitement faded as
> the tweezers confirmed this was a sealant foam and not a wedged
> meteorite in spite of the appearance. The whole floor of the
> compartment was covered in sand-sized, glass particles. In fact, much of
> it looked
> just like mineral sand. At this point I was skeptical that we had a
> meteorite but I could not yet rule out a very friable, high olivine, low
> metallic
> meteorite. So we continued looking and taking samples of the debris.
>
> When extracting the tweezers they dislodged fragments of the culprit.
> The unmistakable components* of a pyrotechnic in the Commercial
> Pyrotechnic class, surfaced out of the sand. It still had the trace
> odor of a burned composition like flash powder or black powder. A
> minute
> particle of tar removed from the windshield also tends to support that
> this was a sealant used to waterproof the explosive. The striations
> apparently came from the parts of the windshield wiper sheared away by
> the blast and not mineral scratches. All the clues came together to
> confirm that this was an explosive and not a meteorite impact.
>
> I participated in post search newspaper interview as to what was found,
> why it was a legitimate event to explore, the common misconceptions
> about meteorites, and the need for public involvement in locating
> meteorites and bringing them into science. I also hope we raised
> awareness
> of the 1995 New Holland, PA Fireball from which a meteorite should have
> dropped but was never found.
>
> Lessons Learned:
> I thought we did a good methodical approach-- avoiding contamination,
> preserving clues and going slow. Having the right tools for looking
> into
> crevices-- telescoping magnet, long tweezers, gooseneck flashlight,
> inspection mirrors, lots of swabs and poly bags-- went a long way at
> keeping the search clean. It was a good hands on opportunity for me to
> expand my search techniques and to compare and contrast the
> tell-tale clues of chemical and kinetic produced damage. ( Add to that
> list survey flags and shovels in case it is over your creel size)
>
> Everyone uses common words and we tend to interpret them within our own
> frame of experience. This tends
> to confuse investigators and raise speculation. It is important in
> interviewing witnesses to bracket their statements between extremes or
> contrasting options to make sure you are accurately envisioning the
> witness's" real "experience. For example I did not see the "burning and
>
> searing" which was first described in email reports. What I did see was
> normal "shearing" and fractures in the windshield and stretching of the
> plastic layer in the safety glass. I had to ask several times what the
> "impact" sounded like. I finally asked was it a "kaboom" or a
> "kuthump"....I
> was told it sounded just like a car crash--like a transformer exploding!
> .... At this point I knew we were talking about a "Kaboom" and not the
> "Kuthump"-- A distinction which is important in accurate identification
> between a chemical blast and a kinetic crash. My advice is to be aware
> of
> this quirk in the manner people describe things. Do not reach an early
> conclusion because they have used a word or description which most of
> the time will be slightly but distinctly different from your use of the
> terms. Check'em ALL out.---Even "trained" observers can be the worse
> culprits!
>
> All persons reporting a possible meteorite are not hoaxers or
> unsophisticated or unlearned people. This family was sincerely
> interested in
> finding the truth and not just finding a meteorite. This did pique their
> interest in meteorites and I anticipate they will soon join the list and
> the hobby.
>
> Finally, for a long while I have wanted to challenge the use of
> regmaglypts in our guides to discovering meteorites... The term is not
> described
> or illustrated sufficiently and meteorites tend to be more smooth than
> bumpy. We really need to go revisit the way we tell the public how to
> identify meteorites. I get photos frequently and can see how people
> reach the conclusion that what they have is a "meteorite" when it is
> clearly
> not in the photo it matches some of the description.
>
> Perhaps soon we can talk about the contents of a recovery/investigators
> kit.
>
> Regards,
> Elton
>
> *Because of a police investigation I was requested to refrain from a
> full disclosure.
>
> _______________________________________________
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Received on Fri 08 Dec 2000 11:35:22 AM PST