Re: earth/moon relationship

Michael Lorrey (
Wed, 29 Oct 1997 21:44:33 -0500

Anders Sandberg wrote:
> writes:
> > And I heard (somewhere,can't remember, no references..but recently....sorry)
> > that some evidence had been "unearthed" that the core of the earth was a
> > single (huge) iron crystal...
> >
> > In accordance with principles set forth in "Demon Haunted World" this
> > bogus? or actually possible.
> I'm not sure, and I'm not a geologist, astrophysicist or even a
> physicist, but I would argue it is unlikely. The core is believed to
> contain not just nickel-iron, but other heavy elements. This suggests
> to me that the core cannot form a nice crystal lattice, and likely has
> an amorphous structure. But a lot likely depends on the behavior of
> this mixture at high pressures and temperatures; things can get rather
> counterintuitive down there, so I wouldn't be totally surprised if it
> occured.
> Is there a geologist in the house? :-)

I'll ask my cousin this weekend up at our hunting lodge. Crystals do not
need to be one element. Crystals are often formed as matrices of
compounds (one example: silicon based crystals for transistor and diode
components are doped with other elements with different valences to make
emitters and acceptors, Gallium Arsenide is another compound that forms
crystals.) When matter is under sufficient pressure, it will crystalize
no matter what its content. The content and the rapidity of
crystalization will, however, determine the homogeneity of the matrix,
as well as the flaw density. I would imagine that there is a decent
amount of other elements besides iron in the core, but iron will still
be the overwhelmingly largest percentage, and that since the core has
been under the same or similar pressure since the time of planetesimal
formation, its present content would be similar to that at the time of
its original formation, so the "crystal" core could be the most original
structure on earth.

			Michael Lorrey
------------------------------------------------------------	Inventor of the Lorrey Drive
MikeySoft: Graphic Design/Animation/Publishing/Engineering
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