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Re: Deathstar?
Y'all,
Deathstar chondrules have been a matter of debate for 20 years.
The two main views are: (1) A solid chondrule made a dent in one that
had just formed, and was still warm and plastic. Had they stuck
together, a compound chondrule would have formed. (2) A fully
molten chondrule contained immiscible metal+sulfide and silicate
melts. The more dense metallic liquid migrated to the surface
because the chondrule was spinning. After solidifaction,
this metal+sulfide bead popped out, and is now an isolated
particle somewhere else. An option (3), that these features
are hypervelocity "zap" pits such as produced during LDEF experiments,
is probably not on the table for most "craters," although there is
some literature arguing for this option as well in a few cases.
I put my money on option (2) in the majority of cases. Sometimes
these "craters" still have opaque minerals in them. The radial
pyroxene and cryptocrystalline chondrules in which they are
common have compositions that are low in siderophile and chalcophile
elements, suggesting that they have lost metal and sulfide. Some
chondrules have dozens of craters, which would require unacceptably
dense chondrule formation regions if they are impact craters.
jeff
At 12:20 PM 9/21/99 , you wrote:
>Seems to have a crater in it, too...
>
>Have a good day, Alex
>
>----- Original Message -----
>From: Martin Horejsi <martinh@isu.edu>
>To: <meteorite-list@meteoritecentral.com>
>Sent: Tuesday, September 21, 1999 11:09 AM
>Subject: Deathstar?
>
>
> > Hi All,
> >
> > I did some analysis of the deathstar image and found a few artifacts that
> > may indicate its origin.
> >
> > See the processed picture at:
> > http://aristotle.isu.edu/deathstar2.jpg
> >
> > It appears the deathstar is so super-massive that its mere gravitational
> > presence casts a shadow over the entire deep sky region behind it.
> >
> > Cheers,
> >
> > Martin
> >
> >
> >
> > ----------
> > >From: Dave Andrews <dandre10@cybertrails.com>
> > >To: Ginger Mayfield <chikadee@earthlink.net>
> > >Subject: Re: Microscope question
> > >Date: Tue, Sep 21, 1999, 8:23 AM
> > >
> >
> > > Ginger Mayfield wrote:
> > >>
> > >> Jim,
> > >>
> > >> I very much enjoyed your photos but I have to ask what is the
> > *deathstar*?????
> > >>
> > >> http://www.arachnaut.org/images/meteor/micro/deathstar.jpg
> > >>
> > >> Ginger Mayfield
> > >
> > > Could that be a stuffed Spanish Olive, floating in brine, with the
> > > pimento removed? Actually, I'm curious too.
> > >
> > > Cheers,
> > > Dave
> > >
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Dr. Jeffrey N. Grossman phone: (703) 648-6184
US Geological Survey fax: (703) 648-6383
954 National Center
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