to the many people with issues regarding the diamond-core theory:
i didn't think it up. nor am i an astrophycist or a chemist - just someone who reads a lot. i can't answer all of your questions. if you want to take this up seriously, ask in sci.astro, or of an applicable scientist you know, or even consult a library. books are, after all, where i heard about the idea in the first place.
puke: as rdouglas said, though, solid is the densest form of most elements. given the pressure at the core of a jovian planet, i'd reckon any carbon present would pretty much have to be in the densest form available. so, it's a
hot diamond.
rdouglas: i think you answered your own question, didn't you? iron is 'heavier' than carbon, so that's what's at the centre. whereas, carbon is 'heavier' than the majority of elements on a jovian, so
that is at the centre instead there.
(sorry it took so long to reply - timezones are a *****
)
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"Just think of it as Evolution in action" -
'Oath of Fealty', by Larry Niven & Jerry Pournelle.