[meteorite-list] The Term "Planetary"

From: MEM <mstreman53_at_meteoritecentral.com>
Date: Fri, 18 Mar 2011 12:05:39 -0700 (PDT)
Message-ID: <627565.47582.qm_at_web161907.mail.bf1.yahoo.com>

Hello Ryan

Planetary doesn't refer so much to exact origin but to the environment of
formation. This is a convention we use to cover meteorites which are derived
from very large parent bodies which extend beyond the limited asteroid
compositions which may also show differentiation-- but to a lesser variety of
mineral compositions and rock types. Be it remembered that our moon is larger
than Mercury. We speak of planetary processes and planetary science. Others
may have details on where it was first used in relation to meteorites. Be it
also remembered that the IAU members still have difficulty coming to grips with
a precise definition of planet.
 It is just a convention please don't read into it too much that it is
restricted to just the named planets.

Just me talking but I think the planetary line are those bodies whose mass is
sufficient to form near spherical bodies --be it within the solar system or
elsewhere in the galaxy. I am aware that most of the minor planets do not
conform to this rule of thumb. Those larger bodies also exhibit a more
sophisticated geological history than say we would find on Vesta.
Elton


----- Original Message ----
> From: "fallingfusion at wi.rr.com" <fallingfusion at wi.rr.com>
> To: meteorite-list at meteoritecentral.com
> Sent: Fri, March 18, 2011 2:44:04 PM
> Subject: [meteorite-list] The Term "Planetary"
>
> To the list,
>
> I was sitting here reading some emails, and just thought...
>
> Who in the world ever came up with the term "Planetary" in reference to
>meteorites.
>
> First of all, our Moon isn't a planet.. and secondly, to my knowledge, the
>only "Planetary" meteorites in current existence have an origin of Mars. Hence,
>"Martian" meteorites. Did I miss the big announcement of those from Venus and
>Mercury?
>
> Regards,
>
> Ryan
Received on Fri 18 Mar 2011 03:05:39 PM PDT