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

From: Rob and Colleen <iguana_at_meteoritecentral.com>
Date: Thu Apr 22 09:37:32 2004
Message-ID: <3A3091E5.452FC72F_at_pcez.com>

Thank you Elton for a well executed, well narrated conclusion to this
proposed fall. I remember hearing the story on the news and saying "Why
can't that happen to me?" Careful what you wish for I guess.
Rob wesel

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 02:46:45 AM PST