Icy Explanation: Newsletter Challenge (February 2014)

Slightly different triple points for the various ice types. Researching it could find the best temperature/pressure combination that would allow this. "Super-Earth-sized" suggests a higher pressure than Earth's atmospheric pressure.

Only constant is temperature, suggested as unvarying, gravity suggested greater than the earths, atmospheric pressure not stated, variable with quantity of gasses, and what is one month on a exoplanet ? out with the charts, anyones guess? Are there any variables?

Regards JD

Ga to you and SE. Your posts were posted nearly simultaneously and the same good link. My guess for the variance of pressure on a large exoplanet would be similar to those found on earth during weather changes of high pressure and low pressure. On a large planet with much greater than 1 earth atmosphere, these fluctuations of atmospheric pressure would be enough of a swing to make ice or not that will be in different phases.

Since this is an engineering forum, and not a pure science forum, we will assume for now that the temperature is slightly above the point where any form of liquid water can exist (for the sake of settling arguments, the correct temperature is -21.985 °C, and certainly not -22.000 °C. This way Solar Eagle, and others, who were onto the answer have it nailed down without any necessary further explanation. An uber-sized planet with have a high atmospheric pressure at the surface (provided it has an atmosphere at all - and this is a requirement to the solution of this month's riddle), and also must have some water present in the atmosphere (not saying that is vapor at the moment). Pressure swings (as stated by others) would be large by earth standards, enough to swing the glass of water from one state to another. The various forms of high pressure ices have been well enough explained.

this could be caused by the sun...cloudy days vs sunny days...night and day could also be a factor..

The problem there is that the OP mentioned the temperature is constant.

Martin the Martian peed into the water glass....

Just saying.

If temp is minus 22 at all times then what is it floating on- if water it would be always frozen.

Well - gotta say I'm glad to see an actual thought-provoking challenge question. It's been a while.

I'm curious what kind of exoplanet will have an atmospheric pressure 2000 times a standard Earth atmosphere, where water and water-ice can be found, and I'd really like to know who put that glass of water out there. Perhaps Isabella is a sentient robot.

I cried "pressure" but than I saw the replies..

No need to be a copycat :(

"Isabella is living in an outpost on the surface of a super-Earth-sized exoplanet."

The OP does not mention the impracticality of actually having a person on station on this planet to place the water/glass, much less witness the effects of local pressure changes. I do believe the pressure is well above any technology we have now for large pressure vessels, including (most) submarines? And we need this to be landing craft (as a minimum) from a mother ship in space? 200MPa is 29,000 psi. Isabella must a robot, and not requiring a pressure suit, then the possibility is limitless.

Isabella cannot be a robot. Consider that Isabella is living... When we get to the point that robots are considered living, I fully anticipate that we will also be able to provide pressure vessels that will allow humans to man an outpost in such a hostile environment. (And although advanced robots would make it unlikely we would NEED to man such an outpost with a human, I'm sure that some Isabella somewhere would jump at the opportunity to do so. People are infinitely curious.)

Sorry I know I am out of time and late with this comment but I only just read the GlobelSpec email / found this forum. : )

I might point out that the technology needed to actually reach this super Earth probably precludes any problems with handling high pressures like 200 MPa. The only way to get out there is basically some kind of FTL technology - and that will require at a minimum things like the ability to create and manipulate black holes, and probably sci-fi force fields and so on.

It seems rather more likely to me that Isabella is a local.

pressure, radiation, gravitation, any thing else?

hot spot in the ground?

frozen water breaks (normal) glass

a cycling planet at an elliptical orbit has seasons

At 251.16 K and 209.9 MPa (remember that this is a super planet) we have a water / ice triple point: Ice III + Ice Ih + Water.

Ice III is denser than water, it sinks. Ice Ih is normal ice, it floats.

Shifting pressure slightly you shift from Ice III to Ice Ih. Shifting temperature slightly you shift from ice to water.

First Isabella must either b an alien or living in a pressure vessel, sort of submarine type thing.

-22C is the right temperature for water to exist in several phases depending on the pressure.

Now if the pressure is some 210MPa then the water may be liquid w/o the formation of ice.

However is the atmospheric pressure is increased Ice is formed known as ICE III which is denser than the water and will sink at the bottom but if the pressure goes down from 210 MPa ordinary ice is formed floating on the water.

Or did I get this upside down:>)

Adnaan