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So Pluto wears diapirs. Ha Ha. Actually, that's really interesting. I had no idea there was such a thing as a diapir. Your comment on eroded volcanoes made me

So Pluto wears diapirs. Ha Ha. Actually, that's really interesting. I had no idea there was such a thing as a diapir. Your comment on eroded volcanoes made me wonder if water on Pluto acts a lot like rock on Earth and if there are water volcanoes that result from sub-surface heat transforming water into liquid.

jheriko 11y ago
if you are interested read some stuff on the subject, there is loads of it around... ice is a sort of equivalent to rock beyond a certain (not as far as pluto by a long way) distance from the sun. astronomers have a funny idea about what the word ice means too...
- S4M 11y ago
  Probably a naive question, but why is it the case? we have the basic formula of thermodynamic: PV = nRT, with n and R being constant, so if I keep the volume the constant and decrease the temperature, it would decrease the pressure P, making the material less hard. What am I missing?
  - pm90 11y ago
    PV = nRT is for ideal _gases_, ice is solid.
  - jheriko 11y ago
    phase transitions are complicated. when something is a gas that rule applies because the forces between the constituent particles are neglible except for the electromagnetic interaction causing scattering (i.e. particles bouncing off each other, or the surroundings). this is the pressure from that formula. increasing temperature increases the energy in the system, resulting in more collisions, and more pressure. decreasing it results in less as you correctly point out. in a solid the electromagnetic interaction is constantly present and locks the constiuent particles nearly in place, so that when excited they 'vibrate' around their location, rather than moving freely like in a gas. this has different consequences, so that decreasing the temperature will increase the rigidity of the material since the particles will become ever less likely to achieve the energy required to escape their electromagnetic 'traps'.

jheriko 11y ago

if you are interested read some stuff on the subject, there is loads of it around... ice is a sort of equivalent to rock beyond a certain (not as far as pluto by a long way) distance from the sun. astronomers have a funny idea about what the word ice means too...

S4M 11y ago
Probably a naive question, but why is it the case? we have the basic formula of thermodynamic: PV = nRT, with n and R being constant, so if I keep the volume the constant and decrease the temperature, it would decrease the pressure P, making the material less hard. What am I missing?
- pm90 11y ago
  PV = nRT is for ideal _gases_, ice is solid.
- jheriko 11y ago
  phase transitions are complicated. when something is a gas that rule applies because the forces between the constituent particles are neglible except for the electromagnetic interaction causing scattering (i.e. particles bouncing off each other, or the surroundings). this is the pressure from that formula. increasing temperature increases the energy in the system, resulting in more collisions, and more pressure. decreasing it results in less as you correctly point out. in a solid the electromagnetic interaction is constantly present and locks the constiuent particles nearly in place, so that when excited they 'vibrate' around their location, rather than moving freely like in a gas. this has different consequences, so that decreasing the temperature will increase the rigidity of the material since the particles will become ever less likely to achieve the energy required to escape their electromagnetic 'traps'.