Greetings. Does anyone know the theories of what is at the core of the Solar system's gas giants? I have heard them described as 'beach balls' with no solid surface - but perhaps with pressure and heat, or cold in some cases, some of them have semi-solid surfaces? Or perhaps very hard surfaces indeed? I think it is in Arthur C. Clarke's 2010 Odyssey Two that he imagines Jupiter's core as a vast diamond (as 'big as the Ritz' if you will Please Register or Log in to view the hidden image!). I suppose no one really know as yet, but are there any theories that the gas giants might have sold cores? And if so, how big are these solid cores? I would suppose any one of the four gas giants (Jupiter, Saturn, Uranus or Neptune) might have a solid core that dwarfs Earth. If I recall, Jupiter actually produces heat, so would that suggest no solid core? What about the others? Do they give off heat? I appreciate any information any of you can share. Thank you all for reading this.