[meteorite-list] Just Another Question

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Sat, 31 May 2008 09:00:37 -0400
Message-ID: <OF58B12EFB.324D7FD5-ON8525745A.0047A65E_at_usgs.gov>

Dear Sterling and list,

Although these reports are intriguing, there is still no convincing
evidence that any of these things are meteorites. I wish I had a
nickel for every "I saw a fireball and collected this weird rock in
my backyard" story I've investigated. That SGU report from 1982 does
not seem to be quoting dogma. The abstract says "Observations of the
bolide connected with the doubtful meteorite Bleckenstad show that,
if a meteorite fell, it could not have happened at Bleckenstad but
far to the south." I haven't read the paper, but it sounds like they
did science.

I have an open mind about the possibility of terrestrial meteorites
(especially on the Moon), but it seems to me that the old Sagan quote
about extraordinary claims applies. Show me the object and show me
the evidence. Until somebody proves it, they are nothing more than wingstars.

Jeff

At 12:08 AM 5/31/2008, Sterling K. Webb wrote:
>Hi, All,
>
> This is an old Post of mine from 2003
>(and quotes from an even earlier one):
>
> "Actually, there are a number of
>sedimentary meteorites. It's just that
>they are not acknowledged to be meteorites.
>If you have the CDROM of the Catalogue,
>have the software assemble you a
>list of "pseudometeorites" that are not irons.
>Or just search for BLECKENSTAD
>(April 11, 1925) SWEDEN, a sedimentary
>meteorite of white limestone complete with
>fossil shells. It was reported on by Dr. Assar
>Hadding of the Swedish Geological Institute
>in 1939 who, after a long investigation, decided
>it really was a meteorite. The chief reason for
>so believing is that it is a WITNESSED FALL
>and you really can't get much better than that.
>
> > BLECKENSTAD,
> > Ostergotland, Sweden, April 11, 1925
> >
> > "A meteor was observed, leaving a trail
> > of smoke. Stones are said to have
> > fallen, and fragments of a white, porous
> > limestone were picked up, differing from
> > the local rocks. The possibly meteoritic
> > nature of this material has been the subject
> > of considerable discussion, N. Zenzen
> > (1942, 1943); A. Hadding (1943); F.C. Cross
> > (1947). Pseudometeorite, F.E. Wickman
> > & A. Uddenberg-Anderson (1982)."
> >
> However, he was widely regarded as whacky
>and shut up about it for 20 years. Hadding was so
>discouraged by the reception of his earlier paper
>that, when he discovered another sedimentary
>meteorite, he threw it away! Only much later,
>in the 1950's, when he realized that they could
>have been "Earthites," did he write about the two
>stones again.
>
> ["Earthites" are meteorites blasted off the Earth
>into independent orbit, then later encounter the
>Earth as a meteoroid. Simulations by Jay Melosh
>suggested the process could take from 100,000
>years to 5 million years.]
>
> The modern SGU official report on the stone:
>http://www.sgu.se/cgi-bin/egwcgi/53210/screen.tcl/name=show_record&format=normal&host=georeg&entry1=0560&field1=kom&logic1=&attr1=&page=2&norec=1&service=sgu&lang=eng
> "The stone described as a limestone...
> hence is a pseudometeorite." (1982)
>
> Boy, there's nothing like dogma for settling
>an issue quickly, is there?
>
> Here is an article by Nininger that contains a
>fuller account of Bleckenstad's fall:
>http://articles.adsabs.harvard.edu//full/1967Metic...3..239N/0000245.000.html
> I can't cut'n'paste from this article because it's
>an image; jump ahead to page 245. A "smooth gloss"
>of a fusion crust is reported. Multiple witnesses to
>the fall. No native limestone in the area.
>
> Monica Grady discusses sedimentary meteorites
>in this 1994 Workshop (p.77):
>http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960027473_1996032004.pdf
>
> Nininger is said to have found a small sedimentary
>meteorite, on March 24, 1933, while searching
>for fragments of Pasamonte. The stone in
>question was a dirty grey limestone with
>fragmentary shell bits fossilized in it and
>sporting a black fusion crust. He ruled out
>an artificial origin for the crust but was unwilling
>to claim it was a meteorite, apparently not because
>he didn't think it was a meteorite but because
>it wasn't worth the noise...
>
> Frank Cross wrote about sedimentary
>meteorites at length in the journal
>"Popular Astronomy" (Vol. 55, 1947,
>pp. 96-102), citing Trevlac (Indiana)
>and Montrose (West Virginia), two
>independently discovered sedimentary
>meteorites with identical green glassy crusts.
>
> The whereabouts of most of the
>sedimentary "pseudometeorites" is
>unknown, not surprising considering
>their reception, so the sophisticated
>tests that could be performed today
>are impossible. There's a kind of
>self-reinforcing judgement at work
>in that."
>
>1. fusion crust, Check.
>2. evidence for cosmic-ray exposure in space, Not Tested.
>3. lithology that is completely exotic for its find location, Check.
>4. being an observed fall, Check.
>5. whereabouts, Unknown.
>
>
>
>Sterling K. Webb
>--------------------------------------------------------------------------
>----- Original Message -----
>From: "AL Mitterling" <almitt at kconline.com>
>To: <Meteorite-list at meteoritecentral.com>
>Sent: Friday, May 30, 2008 7:51 PM
>Subject: Re: [meteorite-list] Just Another Question
>
>
>Hi Pete,
>
> > some material omitted
>
>Jeff states: Nothing like this has ever been found. Its distinguishing
>properties might be a fusion crust, evidence for cosmic-ray exposure in
>space, and lithology that is completely exotic for its find location.
>Without an exposure history (or being an observed fall) it would be a
>very tough sell.
>
>Hope that helps. All my best!
>
>--AL Mitterling
>
>Pete Shugar wrote:
>
> > So if an object were to be taken into orbit and given excape velosity
> > from earth's gravitational well such that it was not in orbit around
> > earth, but in orbit around the sun and at a later time reentered
> > earth's gravity well, passed thru the atmosphere and survived to
> > impact the earth, it would not be a meteorite simply because it was
> > not ejected fron terra firma by natural means? Granted that man made
> > debri isn't classed as a meteorite but non man made material
> > shouldn't be penalized because an astronaught decided to impart
> > excape velosity to a rock,puting it into orbit around the sun.
> > I say material surviving to impact from any source (excluding man
> > made) would and should be called a meteorite.
> > Pete
>
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Dr. Jeffrey N. Grossman phone: (703) 648-6184
US Geological Survey fax: (703) 648-6383
954 National Center
Reston, VA 20192, USA
Received on Sat 31 May 2008 09:00:37 AM PDT