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I kind of like the idea that these gas giants have more rocky planet mass in their cores than all the rocky planets in the solar system combined. Hard to tell,

I kind of like the idea that these gas giants have more rocky planet mass in their cores than all the rocky planets in the solar system combined. Hard to tell, this paper describes the core as mixed with the gases and in fact it may extend out to 1/2 the planet's radius in a fuzzy sort of way. So these cores are not like massive Earths sitting inside with clearly defined boundaries but rather various gradients with fuzzy boundaries as they mix into the rest of the plant's atmosphere. I wonder if Jupiter's core has a similar structure.

sph 3y ago
How can the core be mixed with the gases? I suppose it means the boundary is a massive and eternal dust storm. That's the only way I imagine solids and gases to "mix".
- wffurr 3y ago
  At the pressures in Saturn’s core, the hydrogen and helium aren’t gases anymore, but liquids. Imagine a rock and liquid hydrogen slurry.
- Sharlin 3y ago
  At the pressures and temperatures we’re not talking about either gases or liquids but a supercritical fluid and even more exotic phases, including liquid metallic hydrogen which is thought to be an excellent solvent.
- EVa5I7bHFq9mnYK 3y ago
  It's rocky in the sense that it has elements heavier than hydrogen and helium, but not in the sense that it's solid. Temperature within the cores reaches 40k Celsius, so everything is molten.
Sharlin 3y ago
Yes, based on Juno’s observations it has become more likely that Jupiter’s core is also "fuzzy", having been slowly dissolving into the surrounding metallic hydrogen sea since the planet’s formation and may even have completely dissolved and mixed by now.
- Maursault 3y ago
  Jupiter and Saturn have swallowed a mind-boggling amount of rocky and metallic meteors. They have to go somewhere, and it's unlikely they're just dissolved into the atmosphere. They'll sink to the core and join the others, so there must be some amount of molten rock and metal at the core, negligible to the size of thse planets yet massive compared to the amount that has fallen to Earth.
  - Sharlin 3y ago
    You seem to be speculating based on unfounded assumptions. Luckily we don't have to assume or speculate, because we know quite a bit about the interior of the giant planets these days. > a mind-boggling amount of rocky and metallic meteors. With a total mass a mind-bogglingly tiny fraction of their original rocky-icy cores. Just like with Earth, any post-formation mass increase is a rounding error of a rounding error, because by definition the era of planet formation stopped when the planets ran out of raw material to capture! > They have to go somewhere, and it's unlikely they're just dissolved into the atmosphere. Unlikely by what argument? Essentially anything that falls into one of the giant planets is vaporized high in the atmosphere, long before even hitting the cloud tops! Some of the gaseous meteor stuff may recondense into microscopic dust particles that will remain in the atmosphere due to buoyancy and other forces that vastly exceed gravity at those scales. Any hypothetical chunk of solid matter that somehow falls through the upper atmosphere and the cloud layers intact will encounter a layer of hot supercritical fluid at tremendous pressures, thousands of km thick, and get quickly dissolved. And below the supercritical fluid there's an even more exotic mantle that comprises around 75% of the total mass of the planet and most of its volume. The mantle is made of extremely hot, extremely reactive, exotic liquid metallic hydrogen on observations of the giant planets' magnetic fields. There's absolutely nothing that can fall through that intact even in theory. > So there must be some amount of molten rock and metal at the core No molten rock or metal can exist in the core due to the pressure. However, as I said, there are definitely several Earth masses worth of silicates, and some but not much metal, in the core, because that's the original core that formed first and started attracting gas. Again, the question is whether at least some of that material forms a well-defined solid core, or whether all of it has been dissolved away by the metallic hydrogen mantle surrounding it. The best current models indicate that there's no well-defined boundary and the entire core is "fuzzy" and mixed with the mantle.
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sph 3y ago

How can the core be mixed with the gases? I suppose it means the boundary is a massive and eternal dust storm. That's the only way I imagine solids and gases to "mix".

wffurr 3y ago
At the pressures in Saturn’s core, the hydrogen and helium aren’t gases anymore, but liquids. Imagine a rock and liquid hydrogen slurry.
Sharlin 3y ago
At the pressures and temperatures we’re not talking about either gases or liquids but a supercritical fluid and even more exotic phases, including liquid metallic hydrogen which is thought to be an excellent solvent.
EVa5I7bHFq9mnYK 3y ago
It's rocky in the sense that it has elements heavier than hydrogen and helium, but not in the sense that it's solid. Temperature within the cores reaches 40k Celsius, so everything is molten.

Sharlin 3y ago

Yes, based on Juno’s observations it has become more likely that Jupiter’s core is also "fuzzy", having been slowly dissolving into the surrounding metallic hydrogen sea since the planet’s formation and may even have completely dissolved and mixed by now.

Maursault 3y ago
Jupiter and Saturn have swallowed a mind-boggling amount of rocky and metallic meteors. They have to go somewhere, and it's unlikely they're just dissolved into the atmosphere. They'll sink to the core and join the others, so there must be some amount of molten rock and metal at the core, negligible to the size of thse planets yet massive compared to the amount that has fallen to Earth.
- Sharlin 3y ago
  You seem to be speculating based on unfounded assumptions. Luckily we don't have to assume or speculate, because we know quite a bit about the interior of the giant planets these days. > a mind-boggling amount of rocky and metallic meteors. With a total mass a mind-bogglingly tiny fraction of their original rocky-icy cores. Just like with Earth, any post-formation mass increase is a rounding error of a rounding error, because by definition the era of planet formation stopped when the planets ran out of raw material to capture! > They have to go somewhere, and it's unlikely they're just dissolved into the atmosphere. Unlikely by what argument? Essentially anything that falls into one of the giant planets is vaporized high in the atmosphere, long before even hitting the cloud tops! Some of the gaseous meteor stuff may recondense into microscopic dust particles that will remain in the atmosphere due to buoyancy and other forces that vastly exceed gravity at those scales. Any hypothetical chunk of solid matter that somehow falls through the upper atmosphere and the cloud layers intact will encounter a layer of hot supercritical fluid at tremendous pressures, thousands of km thick, and get quickly dissolved. And below the supercritical fluid there's an even more exotic mantle that comprises around 75% of the total mass of the planet and most of its volume. The mantle is made of extremely hot, extremely reactive, exotic liquid metallic hydrogen on observations of the giant planets' magnetic fields. There's absolutely nothing that can fall through that intact even in theory. > So there must be some amount of molten rock and metal at the core No molten rock or metal can exist in the core due to the pressure. However, as I said, there are definitely several Earth masses worth of silicates, and some but not much metal, in the core, because that's the original core that formed first and started attracting gas. Again, the question is whether at least some of that material forms a well-defined solid core, or whether all of it has been dissolved away by the metallic hydrogen mantle surrounding it. The best current models indicate that there's no well-defined boundary and the entire core is "fuzzy" and mixed with the mantle.

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