[meteorite-list] Northwest Africa Falls - Question
Jeff Grossman
jgrossman at usgs.gov
Sun Jan 18 10:22:44 EST 2009
Please don't misunderstand me... I just said there was reason to be
suspicious from a statistical point of view, and of course there is an
obvious financial motive. But I was not saying that I thought any of
the fall stories were false, since I never even tried to assess them.
So let's see if there is consensus to be found here on these recent
falls. I did a simple reading of the fall accounts and used google
scholar to search for cosmogenic nuclide or other supporting data. Here
are my zeroth order ratings of each fall story:
Chergach - highly likely
Bassikounou - highly likely
Benguerir - probable
Beni M'hira - probable
Bensour - questionable
Oum Dreyga - questionable
The new one - nothing to evaluate
Maigatari-Danduma - ignore since it isn't really in the NWA region
Bensour is such a weak story that I'm leaning towards changing it from a
fall to a find in my database, which is basically what the MetBull
article also said. I'm not even sure how it got listed as a fall. Do any
of you take issue with this?
The Oum Dreyga story also has strange elements. The witnesses saw it
"falling on ... [the] mountains," which probably means that if there was
a real fall, it was very distant. The fact that many of the stones were
weathered also raises my doubts. So I rate this as weak. Anybody want
to take the stand on Oum Dreyga's behalf? Or argue against any of the
ones I called probable or highly likely?
If two are really finds and one is eliminated because it is really not
in this region, then we are left with 4 in the 2000s decade, plus the
new one which remains to be seen. Four is certainly a more palatable
number than eight from a blind statistical point of view, neglecting
other sociological factors.
Jeff
Dr. Svend Buhl wrote:
> Interesting debate. Reminds me on the good old days of the Acedemie
> Francaise, the days before Biot and Chladni, where scientists doubted
> the accounts of local eyewitnesses on rocks falling from the skies for
> sociological reasons.
>
> As far as I am concerned, I still trust the people who measured e.g.
> the cosmogenic radionuclides of the meteorites produced by these
> recent falls. I absolutely doubt that the Swiss or French labs who
> worked on these stones made up their results just to make them fit the
> newspaper reports and eyewitness accounts.
>
> Svend Buhl
>
>
> ----- Original Message ----- From: "Jeff Grossman" <jgrossman at usgs.gov>
> To: "Meteorite-list" <meteorite-list at meteoritecentral.com>
> Sent: Saturday, January 17, 2009 11:27 PM
> Subject: Re: [meteorite-list] Northwest Africa Falls - Question
>
>
>> Martin and list,
>>
>> Actually, there is something suspicious. Northwest Africa (the
>> countries you listed plus Western Sahara and Tunisia) has seen
>> between 0 and 3 falls per decade from the 1900s through the 1980s.
>> The 1990s saw 6, and the 2000s have now got 8. There is no parallel
>> increase in the rest of Africa, which in fact has been steadily
>> declining in fall rates since the 1940s. Europe has also been
>> declining since the 1930s (in fall rates), as has North America. I
>> think northwest Africa is the only place in the world that is seeing
>> any kind of increase in rate, and it has been dramatic, tripling in
>> the last decade.
>>
>> The are various sociological reasons why this increase might have
>> happened, which we can argue about. But there certainly IS something
>> to raise ones eyebrows.
>>
>> Jeff
>>
>> Martin Altmann wrote:
>>> Hi Ryan,
>>> it's because of the iron mountain in Atlas, which still has to be
>>> found and
>>> which attracts with his magnetic field all iron-bearing lumps from
>>> space.
>>>
>>> No. Take a World map, hold little Europe (forget a little bit about
>>> Scandinavia),
>>> hold it against that NWA region, Algeria, Mali, Niger, Morocco,
>>> Mauretania....
>>>
>>> And let's count the falls:
>>>
>>> Let's start with Zag 1998.
>>>
>>> NWA-Regions:
>>>
>>> Zag 1998
>>> El Idrissa 1998
>>> Djoumine 1999
>>> Beni M'hira 2001
>>> Bensour 2002
>>> Oum Dreyga 2003
>>> Maigatari-Danduma 2004
>>> Benguerir 2004
>>> Bassikounou 2006
>>> Chergach 2007
>>> And now the new possible fall.
>>>
>>> Europe:
>>>
>>> Ourique 1998
>>> Leighlinbridge 1999
>>> Moravka 2000
>>> San Michele 2002
>>> Neuschwanstein 2002
>>> Alby sur Cheran 2002
>>> Villalbeto 2004
>>> Moss 2006
>>> Puerto Lapice 2007
>>> Romanian Fall 2008
>>>
>>> 11 : 11.
>>>
>>> So nothing suspicious.
>>>
>>> USA had 7
>>> India 10
>>>
>>> Best!
>>> Martin
>>>
>>>
>>>
>>>
>>> Ok Folks,
>>>
>>> I am curious to know why there are so many witnessed (recovered)
>>> meteorite
>>> falls in Northwest Africa as opposed to anywhere else in the world.
>>> Is there
>>> a good logical and/or scientifc explanation for this?.. or just a
>>> coincidence? I understand that some "falls" simply turn out to be a
>>> case of
>>> Nomadic lies in an attempt to liquidate (recycle) old material, but
>>> what
>>> about the others? Perhpas it has something to do with it's geographical
>>> location in relation to..?
>>> And yes, I do understand these people spend countless hours
>>> outdoors, in the
>>> desert, ect. but..
>>>
>>> What are your thoughts?
>>>
>>> Ryan
>>>
>>>
>>> ______________________________________________
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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
>>
>>
>> ______________________________________________
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>> Meteorite-list mailing list
>> Meteorite-list at meteoritecentral.com
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>
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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
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