XPost: sci.space.policy, sci.astro   
   From: gherbert@retro.com   
      
   Eric Chomko  wrote:   
   >Joseph Lazio (jlazio@adams.patriot.net) wrote:   
   >: >>>>> "RK" == Rodney Kelp  writes:   
   >: RK> When they going to take a look at the surface of Saturn?   
   >: They aren't, and they can't.  In all likelihood, Saturn does not have   
   >: a "surface."  Rather, the atmosphere just keeps getting denser and   
   >: denser as you go deeper.   
   >   
   >Wouldn't it make sense that Saturn, as well as the other gas planets, has   
   >a thick atmosphere, followed by a liquid layer and then a solid layer   
   >(lithoshere). Unlike earth, they would be gradual from gas to liquid and   
   >liquid to solid. Just a theory of course.   
      
   That depends on the planet and its mass.   
      
   One thing to realize is that the pressures are very high   
   (Jupiter's core is at about 80 megabars) and temperatures   
   are also very high (20-30,000 K in the core of Jupiter).   
   Solid metallic hydrogen requires low temperatures.   
      
   Uranus and Neptune probably don't have liquid or solid   
   hydrogen at their cores; they do apparently have a liquid   
   core of water, then some solid ices around an inner rock core,   
   but they don't have enough total mass to compress the   
   hydrogen enough for it to be liquid or solid.   
      
   Saturn apparently has a liquid metallic hydrogen outer core,   
   under layers of gas and liquid hydrogen.  There's a solid   
   rock/ice core at the middle.  The metallic hydrogen isn't   
   compressed enough to be solid.   
      
   Jupiter apparently also has an outer core which is   
   liquid metallic hydrogen, not solid, and an inner core of   
   rock and other solids.   
      
      
   -george william herbert   
   gherbert@retro.com   
      
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