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The Thermodynamic Sinks of this World


Much as I applaud Roald's exercise, I'd like to remind him that the face of the Earth is devoid of the one mineral species that dominates the solar system- metallic hydrogen.

So high are average pressures within the larger planets that their natural history becomes less a matter of mineralogy than metallurgy, for when pressures are reckoned in tens of megabars, the band structure of all solids degenerates into metallic conduction of one sort or another, and many besides carbon may sport adamantine phases , some of which may be metastable at eathly STP just as diamond is.

Sure there will be new exominerals galore, but most will be products of phase separation from metallic melts, and many will be intermetallic compounds of hydrogen and other light elements reduced to metallicity by pressures doubling their earthly density- and effective atomic radii.

I confess to a long speculative infatuation with the possible synthetic mineralogy of systems based on ammonia as a substiute for water as a solvent- a little such work has in fact been done in pursuit of such ammonia-friendly semiconductors as gallium nitride.
posted by Russell Seitz
July 29, 2013 @ 9:03 PM


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