re: Depends what you mean by "solid"
"Many models of Gas giants have a supercompressed "metallic" hydrogen core in which the huge magnetic field is generated. perhaps this would be a shell overlying the rocky and icy core - also supercompressed."
You mean that "this would be a shell" (rocky and icy shell) that OVERLIES the metallic hydrogen core."? That would make more sense to me (it does!).
Great stuff.
