[extropy-chat] Pluto New Horizons launch -getting ready

[Robert Bradbury]

On 2/16/06, Amara Graps <amara at amara.com> wrote:
>
>
> Robert Bradbury:
> >But meteorites are rather stupid when it comes to avoiding long
> >residence times within a hot plasma.
>
> ?? A strange statement, can you explain what does this mean?


I  was intending it to mean the hot plasma which may be generated by the
impact itself.  For example there isn't a large meteor body at the bottom of
Meteor Crater [1].  Presumably this is because much of it was vaporized upon
impact.

(unless it is a joke on the fact that 99% of the universe is a plasma,
> including our solar system)


It took me a while to understand this (particularly when they called it "hot
plasma").  If I understand it correctly now this is because astronomers are
relating temperature to the ionization state of the atoms/molecules
(yes???).  However I question the number of 99% as I'm not under the
impression that most material at stellar cores is in a plasma state (though
I'm willing to be corrected).

Of course one thing that has always bothered me about "hot" interstellar
ions/molecules is *where* the hell are all of the electrons?

BTW, it _is_ odd how dense and compact are meteorites when compared
> to how porous are their parent bodies, isn't it? (should be a few
> PhD theses in answering that question)


I thought I saw a paper recently that attributed at least the iron
meteorites to having a limited set of sources (planetesimals) which were
large enough to have undergone gravitational compression.

Robert


1. http://sped2work.tripod.com/meteroite.html
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