4 ms·

Shouldn't the solid surfaces of the gas giants be on this map?

Retric 9y ago
My understanding is they don't have solid surfaces as far as we can tell. Both the temperature and pressure gets extreme which breaks down the difference between solid/liquid/gas.
Sharlin 9y ago
The gas planets are complicated. They most likely don't have anything that could be called a well-defined solid surface beneath all that gas. We really don't know the details, but Jupiter and Saturn are thought to be something like this: * Gas, mostly helium and hydrogen with trace amounts of other gases * Cloud layers of ammonia, ammonium hydrosulfide, and water. * More gaseous hydrogen and helium, lots and lots of it * Hydrogen and helium in the form of supercritical fluid. Above the critical point there are no distinct liquid or gas phases. * A thick layer of liquid metallic hydrogen. Really exotic phase of matter; huge currents flowing through it are thought to cause Jupiter’s extreme magnetic field. * Finally, a solid core of some sort, not much is known about it. At those pressures and temperatures it must be pretty exotic. It may not have a well-defined boundary; hot metallic hydrogen is thought to be a ridiculously good solvent. Uranus and Neptune are different; they're usually referred to as "ice giants" these days. Beneath the atmosphere they are thought to have a thick mantle made of various exotic hot ices (mostly water, ammonia, and methane), and beneath that a small silicate/iron-nickel core.
- codeflo 9y ago
  > metallic hydrogen It makes sense from the periodic table, but I really didn't know this existed. Very cool!
  - Sharlin 9y ago
    Its existence was predicted in 1935 and it’s still pretty theoretical. But it’s pretty much the only thing that could explain Jupiter’s magnetic field. Just last year experimentalists claimed to have produced metallic hydrogen in a diamond anvil, but those results are under some scrutiny and AFAIK haven’t been reproduced yet.
  - thaumasiotes 8y ago
    > It makes sense from the periodic table I've seen a quick-and-dirty summary of how to think about bonds that goes like this: - An ionic bond forms between two atoms, one of which has too many electrons and one of which has too few. They balance. - A covalent bond forms between two atoms, both of which have too few electrons. Some electrons are shared between both atoms simultaneously, bringing each up to quota through the simple magic of double-counting. - A metallic bond forms "between" some number of atoms which all have too many electrons. The surplus electrons roam back and forth freely around the metal because their home atoms would prefer them to go away, allowing the metal to carry electric current. This model is supposed to explain why you can basically combine arbitrary metals in arbitrary ratios and still get a metal. It also seems like it predicts the existence of metallic hydrogen, in that a normal H ion is positive. Does that actually make sense?
- ByThyGrace 8y ago
  What's a hot ice? What's a non-hot ice (is it just "ice")? What kind of ice is the water ice we find here on Earth naturally?
  - Sharlin 8y ago
    We're accustomed to associating the word "ice" with temperatures less than 273 K, the freezing point of water at 1 bar. It takes even lower temperatures for ammonia or methane to solidify. But it's definitely not freezing deep within a planet, the temperatures are thousands of kelvins! However, the pressures are from thousands up to millions of bars, which is plenty enough to keep pretty much anything solid even at those temperatures. The allotrope of solid water we're familiar with is called ice I_h (Roman numeral "I" followed by subscript "h" for "hexagonal"). It has the interesting and vital property of being less dense than liquid water and thus you cannot get ice I_h by compressing water. But there are many other, more exotic phases of ice, most of which are denser than liquid water and can thus form under extreme pressures. Indeed, in a sense they're not that exotic after all, seeing that almost all the water in the Solar System is in the form of high-pressure ices!
- jobigoud 8y ago
  I always liked the idea of an object that transitions smoothly from solid to liquid without a well defined boundary. Does such objects exist on Earth?

My understanding is they don't have solid surfaces as far as we can tell. Both the temperature and pressure gets extreme which breaks down the difference between solid/liquid/gas.

Sharlin 9y ago

The gas planets are complicated. They most likely don't have anything that could be called a well-defined solid surface beneath all that gas. We really don't know the details, but Jupiter and Saturn are thought to be something like this: * Gas, mostly helium and hydrogen with trace amounts of other gases * Cloud layers of ammonia, ammonium hydrosulfide, and water. * More gaseous hydrogen and helium, lots and lots of it * Hydrogen and helium in the form of supercritical fluid. Above the critical point there are no distinct liquid or gas phases. * A thick layer of liquid metallic hydrogen. Really exotic phase of matter; huge currents flowing through it are thought to cause Jupiter’s extreme magnetic field. * Finally, a solid core of some sort, not much is known about it. At those pressures and temperatures it must be pretty exotic. It may not have a well-defined boundary; hot metallic hydrogen is thought to be a ridiculously good solvent. Uranus and Neptune are different; they're usually referred to as "ice giants" these days. Beneath the atmosphere they are thought to have a thick mantle made of various exotic hot ices (mostly water, ammonia, and methane), and beneath that a small silicate/iron-nickel core.

codeflo 9y ago
> metallic hydrogen It makes sense from the periodic table, but I really didn't know this existed. Very cool!
- Sharlin 9y ago
  Its existence was predicted in 1935 and it’s still pretty theoretical. But it’s pretty much the only thing that could explain Jupiter’s magnetic field. Just last year experimentalists claimed to have produced metallic hydrogen in a diamond anvil, but those results are under some scrutiny and AFAIK haven’t been reproduced yet.
- thaumasiotes 8y ago
  > It makes sense from the periodic table I've seen a quick-and-dirty summary of how to think about bonds that goes like this: - An ionic bond forms between two atoms, one of which has too many electrons and one of which has too few. They balance. - A covalent bond forms between two atoms, both of which have too few electrons. Some electrons are shared between both atoms simultaneously, bringing each up to quota through the simple magic of double-counting. - A metallic bond forms "between" some number of atoms which all have too many electrons. The surplus electrons roam back and forth freely around the metal because their home atoms would prefer them to go away, allowing the metal to carry electric current. This model is supposed to explain why you can basically combine arbitrary metals in arbitrary ratios and still get a metal. It also seems like it predicts the existence of metallic hydrogen, in that a normal H ion is positive. Does that actually make sense?
ByThyGrace 8y ago
What's a hot ice? What's a non-hot ice (is it just "ice")? What kind of ice is the water ice we find here on Earth naturally?
- Sharlin 8y ago
  We're accustomed to associating the word "ice" with temperatures less than 273 K, the freezing point of water at 1 bar. It takes even lower temperatures for ammonia or methane to solidify. But it's definitely not freezing deep within a planet, the temperatures are thousands of kelvins! However, the pressures are from thousands up to millions of bars, which is plenty enough to keep pretty much anything solid even at those temperatures. The allotrope of solid water we're familiar with is called ice I_h (Roman numeral "I" followed by subscript "h" for "hexagonal"). It has the interesting and vital property of being less dense than liquid water and thus you cannot get ice I_h by compressing water. But there are many other, more exotic phases of ice, most of which are denser than liquid water and can thus form under extreme pressures. Indeed, in a sense they're not that exotic after all, seeing that almost all the water in the Solar System is in the form of high-pressure ices!
jobigoud 8y ago
I always liked the idea of an object that transitions smoothly from solid to liquid without a well defined boundary. Does such objects exist on Earth?