[meteorite-list] Meteorite Questions

From: Bill <glixard_at_meteoritecentral.com>
Date: Wed, 29 Aug 2007 22:27:11 -0800
Message-ID: <8A2E0A63BCE.000008CDglixard_at_inbox.com>

I think what's lurking in this material is a wish to be able to predict.

Bill



> -----Original Message-----
> From: sterling_k_webb at sbcglobal.net
> Sent: Thu, 30 Aug 2007 00:43:00 -0500
> To: meteorite-list at meteoritecentral.com
> Subject: Re: [meteorite-list] Meteorite Questions
>
> Hi, All,
>
> This is the notion of "meteoroid streams" (as opposed
> to the "meteor streams" of a comet. Meteoroid streams would
> have an asteroidal origin. This idea was a big back-and-forth
> controversy in the XIXth century. One problem is that the term
> "meteoroid streams" is now being used for both cometary
> AND asteroidal streams. Sloppy usage.
>
> There ARE asteroidal non-cometary meteoroid streams:
> http://www.lpi.usra.edu/meetings/lpsc2007/pdf/2038.pdf
> and of course there could be many more if they are composed
> of objects too small to be easily detected (yet).
>
> Venus has a convergence of both kind of streams, so
> apparently Venus gets plenty of meteorites (if they can survive
> the hellacious trip through its atmosphere... I don't think so.)
> http://www.ingentaconnect.com/content/bsc/mnr/1998/00000294/00000002/art00009
>
> There are nine "cometary" meteoroid streams that are
> actually associated with an asteroid instead of a comet,
> unless of course, that asteroid is a "dead" comet... The
> best known of the nine is the Geminids and the asteroid
> 3200 Phaethon.
> http://www.ingentaconnect.com/content/klu/moon/2005/00000095/F0040001/00002243
>
> A chemical argument that H chondrites come from "meteoroid
> streams" and that they can be grouped by what "stream" they
> come from and that the composition of streams changes only
> very slowly over time:
> http://www.agu.org/pubs/crossref/1997/97JE00137.shtml
>
> Obviously, no gravitational influence great enough to separate
> two adjacent rocks in a short period of time could exist for a
> "meteoroid stream," or pretty soon --- No Stream! The key to
> having meteoroid streams at all is that the Universe leaves them
> alone and does not mess with them...
>
>
> Sterling K. Webb
> ------------------------------------------------------------------------
> ----- Original Message -----
> From: "Maria Haas" <dragonsoup at msn.com>
> To: "TheMeteorite-list" <meteorite-list at meteoritecentral.com>
> Cc: "Walter Branch" <waltbranch at bellsouth.net>
> Sent: Thursday, August 30, 2007 2:53 AM
> Subject: Re: [meteorite-list] Meteorite Questions
>
>
> Walter asked:
>
>> Also, I have read that some meteoroids travel through space in streams
>> and
>> impact the Earth simultaneously (i.e., they have already broken up
>> before
>> they hit the Earth's atmosphere). How can this be? I would think that
>> once
>> a meteoroid has broken in space (most likely due to impact), minute
>> deviations of the individual pieces in the initial trajectory would
>> translate into ever increasing deviations in the individual piece's
>> trajectory, over time. Unless two pieces were traveling in EXACTLY
>> parallel
>> lines, over time the pieces would be widely dispersed in space.
>
>
> >From Robert Haag's 2003 Collection of Meteorites, Page 89:
> "Saint Severin (large at top) 3.1 kilos, and Ensisheim (small, bottom) 85
> grams.
> Amphoterite chondrites (LL6) 20% total iron. These meteorites are both
> historically and scientifically important - while they fell over 500
> years
> apart, they landed within 100 miles of one another and are chemically and
> visually identical. In fact, when placed side by side, they appear to be
> from one contiguous piece. Saint Severin fell June 6, 1966 and Ensisheim
> fell November 16, 1492. Obviously they come from the same asteroid parent
> body."
>
>
> To expand on Walter's question -- whether they travel in streams or
> rubble
> piles, any idea how these two could fall so many years apart and within
> such
> a close proximity of each other?
>
> Are there others that have fallen "together" like Saint Severin and
> Ensisheim?
>
> Maria
>
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Received on Thu 30 Aug 2007 02:27:11 AM PDT