Is there any corollary between the rocky core of a gas giant and a rocky planet like Earth? The article notes there is little data, but ever since reading 2001: A Space Odyssey in high school I've been fascinated by what we don't know under the surface. Or are the pressures just so different that trying to picture a rocky planet (or molten core of a rocky planet) at the center of a gas giant a poor approximation?
2010: Odyssey Two Goes into a little detail as to what may be at the center of Jupiter. Clarke surmised that it my be a gigantic diamond. Is it true? We don't really know. It is very hot, possibly as high as 56,000 K, and very dense. The central core pressure is estimated to be 100 million times the atmospheric pressure at the earth's surface.It is expected from a variety of planet formation scenarios that the planet has a rocky core of about 10-15 times the mass of the Earth, but on top of this is a seething 'ocean' of metallic hydrogen and other exotic states of hydrogen and helium, its chief constituents. Whether the central rocky core is in the form of a 'diamond' or not is not something that could be easily anticipated from the mathematical modeling of the planet's interior. In other words, Arthur's guess is as good as anyone!