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Comment by quotemstr | Hacker News Reader

It's not really an "ocean" in the way we think of such things. In the outer solar system, ice is a rock in the same way granite is a rock. What Titan has isn't so much an ocean as an interior layer of molten ice --- just as our planet has an interior layer of molten rock.

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What's the difference between "molten ice" and water? Is it still crystalline? Is it just the pressure is different, or is there actual physical differences?

Perhaps by "molten ice" he means that the H20 is in its liquid state not because of the surrounding temperature but because of the pressure exerted upon it by the upper layers. Just a guess.

I don't think it's so much a physics/chemical difference, but more to the effect that here on Earth, the ocean is a large body of water that sits on top of the stuff the Earth is actually made of (which is a solidified crust on top of the semi-liquid rock of the mantle)

On Titan, the role of the semi-liquid rock is played by the "ocean" (and the crust is played by the solid water ice layer ontop).

I see no special "molten ice":

http://en.wikipedia.org/wiki/Triple_point#Other_triple_point...

It might have an exotic form of ice, of course.

Can you expand? Why does the article call it "liquid water?"

It's "liquid water" in the same sense that the molton rock inside the earth is "liquid rock".

Here when we see water outside of it's natural state (liquid) it's frozen or evaporated. Out there ice (solid) is the natural state, so it's molten or (vaporized ???).

If it's subterranean, it's probably not vaporized. Thank the pressure.

Oh, definitely. I was (poorly?) highlighting that molten/frozen/vaporized/etc are used relative to the normal state for a substance at "local" temperature.

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