Crushed Water

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PsychoticEpisode

It is very dry in here today
Valued Senior Member
Lot of questions, sorry about that, but I figure there’s enough experts here that can answer them.

Can water be crushed into a solid? AI says yes but I’m not too trusting of it. If water can form into a solid under immense pressure then would it be ice as we know it or actually be a warm or even a hot solid? Is it possible that there are water planets with ice at its surface but with some sort of exotic core that formed as a result of water pressure at much greater depths than here on Earth? Are there different grades for solids made from crushed water?
 
PsychoticEpisode said:
Lot of questions, sorry about that, but I figure there’s enough experts here that can answer them.

Can water be crushed into a solid? AI says yes but I’m not too trusting of it. If water can form into a solid under immense pressure then would it be ice as we know it or actually be a warm or even a hot solid? Is it possible that there are water planets with ice at its surface but with some sort of exotic core that formed as a result of water pressure at much greater depths than here on Earth? Are there different grades for solids made from crushed water?
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There are high pressure phases of ice, as you can see from this phase diagram:

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So under pressures >1Gpa (~10,000 atmospheres), yes presumably you could get liquid water to freeze by application of pressure. But it would have a different crystal structure from normal ice and would not be stable at ambient pressure.
 
PsychoticEpisode said:
Is it possible that there are water planets with ice at its surface but with some sort of exotic core that formed as a result of water pressure at much greater depths than here on Earth?
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Sure. In fact, if our deepest ocean were 10x deeper, we'd have solid water at the bottom of them as well. (Have to be deeper than 100km; right now the deepest part of the ocean is 11km.)
 
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Have you heard of Ice VII or Superionic ice? I assume that is ice that exists at high temperatures. I thought that the more pressure ice is under lowers its melting point.
 
i had trouble with that diagram but making more sense now after some serious study. It looks to me as if and when mankind ever gets the tech to land on an ice ball water world that a hydrologist will be part of the crew.

Once the pressure gets up around 100Gpa then Ice VII, VIII, X & XI appear and the temps range from above to below 0°. How can ice be both super cold and hot? Does it depend on whether the pressure was originally applied to water while in ice, liquid or vapor state?
 
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PsychoticEpisode said:
i had trouble with that diagram but making more sense now after some serious study. It looks to me as if and when mankind ever gets the tech to land on an ice ball water world that a hydrologist will be part of the crew.

Once the pressure gets up around 100Gpa then Ice VII, VIII, X & XI appear and the temps range from above to below 0°. How can ice be both super cold and hot? Does it depend on whether the pressure was originally applied to water while in ice, liquid or vapor state?
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Substances can vary a lot in form according to the prevailing temperature and pressure. Water is no exception.

The phase diagram shows you what phases prevail under different conditions at equilibrium. This does not depend on where you start from. You could in principle prepare a sample of ice VII at 50C and 10Gpa either starting with liquid water at 1 atm and 50C or vapour at 10 atm and 150C. Similarly a sample of ice VII at 50C would be expected to revert to liquid once the pressure is reduced to 1atm, or to vapour at 0.1atm.

However the phase diagram does not tell you anything about rates of change when conditions are altered. In other words it tells you the thermodynamically stable phases but does not tell you about the kinetics of changing from one phase to another. I looked this up and find that ice VII is said to be metastable, which implies it takes time to change when the pressure is reduced. I could not find out how long it takes to change though. (It would be fun if it takes more than a few minutes, in which case you could in principle get a sample and drop it in your gin and tonic, whereupon it would sink to the bottom as it is denser than water, unlike normal ice.)

I also found ice VII seems to be thought important in the physics of the outer planets. (Perhaps this is why you are asking about it?) I also found that it is even said to be a terrestrial "mineral", due to the discovery of inclusions of ice VII within certain specimens of diamond! Presumably the diamond, which was formed under great pressure within the Earth, is able to maintain that pressure internally and keep the ice in its VII phase.

(As a matter of fact diamond is itself a phase of carbon which is technically only metastable at ambient temperature and pressure, though the rate of change to graphite is infinitesimally slow.)
 
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PsychoticEpisode said:
It looks to me as if and when mankind ever gets the tech to land on an ice ball water world that a hydrologist will be part of the crew.

Once the pressure gets up around 100Gpa then Ice VII, VIII, X & XI appear and the temps range from above to below 0°. How can ice be both super cold and hot? Does it depend on whether the pressure was originally applied to water while in ice, liquid or vapor state?
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I wish I could find the citation but I read recently that, on some (hypothetical) ocean worlds, there will be no water surface; it will simply get denser and denser, with smooth transitions from gas to liquid to solid.

But I don't think we'll have to worry about human exploration of planets with 100GPa pressures anytime soon.
 
DaveC426913 said:
I wish I could find the citation but I read recently that, on some (hypothetical) ocean worlds, there will be no water surface; it will simply get denser and denser, with smooth transitions from gas to liquid to solid.

But I don't think we'll have to worry about human exploration of planets with 100GPa pressures anytime soon.
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Well if the pressure and temperature regime is above the critical point there is no distinction between liquid and vapour. It’s just a fluid.

But I have not heard of an equivalent condition for liquid vs. Solid, unless I suppose we are talking about a glass, i.e. an amorphous solid.
 
exchemist said:
I also found ice VII seems to be thought important in the physics of the outer planets. (Perhaps this is why you are asking about it?)
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Didn’t start off that way. Friend brought over something called hydrophobic sand. Immersed in water it doesn’t get wet. Somehow we got on the topic of dropping the stuff into a deep part of an ocean and how far down would it have to be before pressure breaks it up or sand loses its hydrophobic nature. That sand was interesting in itself but don’t want to stray off topic. One thing led to another and yes, water planet, extremely deep oceans and topic of what happens to water when under incredible pressure came up. Exchem has provided excellent answers. There was no way we would rely on AI.
 
In the Learn Something Everyday category. If you’ve ever wondered how scientists recreate high pressures then the Diamond Anvil Cell is the device. Have read where it can create ice and high temps as well as significantly high water pressure. Two diamonds, a metal gasket with a small hole and a tiny amount of whatever you need to compress in between. Special machines analyze what they find after they’ve bombarded the sample with light, x-rays and lasers. Science is amazing.
 
PsychoticEpisode said:
In the Learn Something Everyday category. If you’ve ever wondered how scientists recreate high pressures then the Diamond Anvil Cell is the device. Have read where it can create ice and high temps as well as significantly high water pressure. Two diamonds, a metal gasket with a small hole and a tiny amount of whatever you need to compress in between. Special machines analyze what they find after they’ve bombarded the sample with light, x-rays and lasers. Science is amazing.
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Yeah it would be hard in practice to get a nice cube of ice VII to drop in your gin and tonic. :)
 
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