[meteorite-list] new formation mechanism

[E.P. Grondine]

Hi Sterling, all - 

The question is what was happening between Mars and
Jupiter, and when.

The thing that always got to me in this was the
differentiation in meteorites, which seemed to me to
indicate graviational diffentiation in one or more
LARGE bodies.

As for possible parent size, what was the Titus-bode
prediction for the region?

good hunting all, 
Ed




--- "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
wrote:

> Hi, Ed, List,
> 
>     The only "new" part is the notion that these
> early
> planet-sized bodies get all their crusty mantles
> knocked
> off their cores right away. Think of it as the
> "Naked 
> Core Theory"!
> 
>     General consensus, dating all the way back to
> Wetherill and demonstrated by more recent computer
> simulations, is that the inner solar system requires
> the following minimum set of ingredients:
>     1000 1000-kilometer planetesimals
>     100   3000-kilometer planetesimals (Moon-sized)
>     10     5000-kilometer planetesimals
> (Mercury-sized)
>     2-3    8000-kilometer planetesimals (Mars-sized)
>     Directions: STIR WELL!
> 
>     The truth is, if you start your computer
> simulation with
> only 1000 1000-kilometer planetesimals, you may not
> get
> a solar system at all -- too puny. It's usual to
> start with about
> 10,000 1000-kilometer planetesimals!
> 
>     Picture all 1000 or 5000 or more, all bigger
> than the Dwarf
> Planet 1 Ceres, careening around the inner solar
> system, bonk,
> bonk, bonk! like a pinball game! Would you be
> surprised if
> a lot of them lost all or most of their crust and
> mantle to
> impacts?
> 
>     In fact, if we going to take this Naked Core
> Planetesimal
> Theory seriously, why do we need ANY special case,
> like
> a Big Whack, to explain why Mercury has such a big
> core
> and such a small mantle? Couldn't it have accreted
> directly
> from these planetesimals that are mostly core?
> 
>     It's always better when some puzzle is explained
> as a
> direct result of the prevailing conditions and
> doesn't need 
> a special mechanism to account for it!
> 
> 
> Sterling K. Webb
>
-----------------------------------------------------------------------
> ----- Original Message ----- 
> From: "E.P. Grondine" <epgrondine at yahoo.com>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Thursday, April 19, 2007 9:45 PM
> Subject: [meteorite-list] new formation mechanism
> 
> 
> Hi - 
> 
> And just to think, only a few years ago I constantly
> got reminded about McSween's Meteorites and Their
> Parent Bodies whenever I brought the topic of a
> larger
> parent body up.
> 
> Now we have the LPBE, that was 3.8 or 4.2 Gya, or
> both?
> 
>
<http://www.hawaii.edu/cgi-bin/uhnews?20070418141659>
> 
> 
> good hunting all, 
> Ed
> 
> 


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