Re-2: [meteorite-list] Moss Meteorite From A Comet?

[E.P. Grondine]

Hi Larry, List - 

It appears we have at least one other comet sample:
Cheimgau.

good hunting,
Ed


--- Larry Lebofsky <lebofsky at lpl.arizona.edu> wrote:

> Hi all:
> 
> Defending Tim Swindle and Humberto Campins. I have
> known them for years and 
> they are very conservative scientists. Their work is
> good and they are well-
> respected scientists. They do not go off (too often)
> to make wild, 
> unsubstantiated, claims., hence, the conclusions in
> their article. They based 
> their Meteorite paper (and their original scientific
> paper) on what we know. 
> We have observations of many comets (Campins has
> done a lot of this), but we 
> have "samples" from only one comet (Halley), are
> just now studying Stardust 
> material (so too early to say much), and IDPs which
> are thought to be, at 
> least in part, cometary in origin.
> 
> Clearly, we need multiple samples from multiple
> comets --- good luck in our 
> lifetime. Therefore you base your "theories" on the
> existing information, not 
> onwhat you hope to have in the future. That is why
> people propose new missions 
> to comets and asteroids!
> 
> We know that not all comets are the same based on
> our observations and where 
> we think they came from. Some of this may be because
> of how many times they 
> have been close to the Sun, some may have to be
> related to where they came 
> from (Kuiper Belt or Oort cloud), and some may have
> to do with where they were 
> formed (which may not have been where we see them
> coming from). Clearly, a 
> chunk of a "fresh" comet would look very different
> from a "dead" comet. Or, as 
> been on this listserv recently, could we tell the
> difference between a chunk 
> of a comet or a piece of Ceres? I am not sure I
> would be willing to say 
> anything in print even though I have studied Ceres
> for years. What, from 
> either, would we expect to make it through the
> atmosphere?
> 
> Even if we were to bring back samples from two or
> three comets, I doubt if 
> anyone I know would be willing to say (with respect
> to the composition of 
> comets) that that was their "final answer." That is
> the nature of science.
> 
> I really have to stop writing these a 5:00 in the
> morning, no breakfast and no 
> soffee, but this is the quiet time of the day.
> 
> Larry
> 
> 
> 
> Quoting bernd.pauli at paulinet.de:
> 
> > "Comets ... being 'primitive material' ... we
> would need
> >  to have known multiple samples of multiple comets
> before
> >  we could say for sure."
> > 
> > Hi Mark and List,
> > 
> > I couldn't agree more and that's why I felt a bit
> uneasy when I read
> > Campins' and Swindle's article in this issue of
> our METEORITE magazine:
> > 
> > CAMPINS H. and SWINDLE T.D.(2006) Where are the
> cometary
> > meteorites? (Meteorite, May 2006, Vol. 12, No.2,
> pp. 17-19).
> > 
> > They solely refer repeatedly to Comet Halley and
> to Halley dust (plus to
> > cometary IDPs). Many more comets need to be
> sampled before we can draw
> > definite conclusions!
> > 
> > Best,
> > 
> > Bernd
> > 
> > ______________________________________________
> > Meteorite-list mailing list
> > Meteorite-list at meteoritecentral.com
> >
>
http://six.pairlist.net/mailman/listinfo/meteorite-list
> > 
> 
> 
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