Is it likely that gas giant planets like Jupiter have liquid water oceans beneath the atmosphere (as in Ben Bova's novel Jupiter) or would there just be an ocean of liquid hydrogen?
What about Uranus or Neptune-type worlds?
Oceans on gas giants?
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granthutchison
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The water would be a long way down on Jupiter - its rock/ice core is expected to be only about 10000km in radius, and the transition to metallic hydrogen takes place about 12000km below the cloud-tops - so that's nearly 50000km of hot metallic hydrogen between you and the water.
On Uranus and Neptune the pressures never get high enough to produce metallic-phase hydrogen, and since (as on Jupiter and Saturn) the temperatures are above hydrogen's critical temperature, there's no abrupt transition to liquid hydrogen as pressure increases - just a gradual thickening towards something very like the liquid phase. Then about 5000km down you'd reach "water" - what The New Solar System describes with the sentence: "Although the term "ice" denotes a combination of water, methane and ammonia, under the high temperatures and pressures deep within the giant planet this mixture actually will be a hot liquid soup of various chemical species derived from these molecules." Temperature >2000K, pressure >10000 atmospheres.
Grant
On Uranus and Neptune the pressures never get high enough to produce metallic-phase hydrogen, and since (as on Jupiter and Saturn) the temperatures are above hydrogen's critical temperature, there's no abrupt transition to liquid hydrogen as pressure increases - just a gradual thickening towards something very like the liquid phase. Then about 5000km down you'd reach "water" - what The New Solar System describes with the sentence: "Although the term "ice" denotes a combination of water, methane and ammonia, under the high temperatures and pressures deep within the giant planet this mixture actually will be a hot liquid soup of various chemical species derived from these molecules." Temperature >2000K, pressure >10000 atmospheres.
Grant
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granthutchison
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Seems so. The various cross-sectional diagrams I've seen always place the "ice" at the core of the giant planets. The density of liquid hydrogen is only a tenth that of water at atmospheric pressure, and it ramps up towards 1gm/cm^3 as the pressure rises to 1.4megabars, at which point (or thereabouts) there's a transition to metallic hydrogen with a reported density of 1.15g/cm^3. But graphs for water show its density around 2g/cm^3 at that pressure. So it would seem that the hydrogen should always float on the water.chaos syndrome wrote:So any liquid water ocean would definitely be beneath the liquid hydrogen.
Grant
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granthutchison
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For Jupiter and Saturn, apparently yes, but I'm not sure anyone has actually made solid metallic hydrogen, so I'm guessing the graph I have in The New Solar System is largely theoretical. It shows that Jupiter and Saturn never produce enough pressure to make solid hydrogen, and that brown dwarfs produce more pressure but are also hotter, so they lie even farther from the solid zone.chaos syndrome wrote:Let me just check: the metallic hydrogen in a gas giant is liquid all the way down, right?
Grant