Charon has Geysers too Options

[SigurRosFan]

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The only mechanism that explained the data was cryovolcanism, the eruption of liquids and gases in an ultra-cold environment.

This action could be occurring on timescales as short as a few hours or days, and at levels that would recoat Charon to a depth of one millimeter every 100,000 years.
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- Charon: An Ice Machine in the Ultimate Deep Freeze

[Rob Pinnegar]

Hmm. This is interesting.

I wouldn't have thought that something as small as Charon could still have liquid water in its interior. This isn't like Enceladus or Miranda where a big gas-giant planet is available to power tidal heating.

Just to speculate: My understanding is that a lot of the Earth's uranium floated to the crustal layer during the planet's formation. You'd expect such a heavy element to sink, but uranium likes to combine chemically with oxygen, and that provides it with a lot of buoyancy.

On a body like Charon, though, the uranium would only be able to float to the top of the core -- where it would remain, insulated by a 500-km-deep layer of ice. So should we expect ice/rock bodies like Pluto, Charon and Triton to hold onto their radiothermal heat more efficiently than similarly-sized rocky bodies? (Assuming we could find any similarly sized rocky bodies, of course.)

[Littlebit]

Just to speculate: My understanding is that a lot of the Earth's uranium floated to the crustal layer during the planet's formation. You'd expect such a heavy element to sink, but uranium likes to combine chemically with oxygen, and that provides it with a lot of buoyancy.

There is also the chromographic soil effect: At a nuclear facility near Hanford, Washington, extremely low concentration radioactive wastes were dumped in an evaporative sludge pond. Over time (probably decades), elements were chomographically separated in the clay, and a layer of high energy waste was concentrated naturally near the surface to an unnatrual level - almost self sustaining.

I also have a questionable account about how the problem was discovered: rabbits managed to get through the fence and nibble on grasses growing in the pond. Routine radioactive measurements taken outside of the fence uncovered radioactive rabbit pellets...

[Juramike]

There is also the chromatographic soil effect: At a nuclear facility near Hanford, Washington, extremely low concentration radioactive wastes were dumped in an evaporative sludge pond. Over time (probably decades), elements were chromatographically separated in the clay, and a layer of high energy waste was concentrated naturally near the surface to an unnatrual level - almost self sustaining.

Likely nucleides for heating mantles (at least for Earth) are Uranium, Thorium, and Potassium-40.

According to Wikipedia (my copy of Cotton and Wilkenson's is back at the office), uranium likes being in oxidation states U(+4) or U(+6), with the most common form in nature (terrestrial conditions) being U3O8. "Both oxide forms are solids that have low solubility in water and are stable over a wide range of environmental conditions."

But at the bottom of an ammonia water ocean, what would be the preferred form?

Would it be a uranium hydroxide (U[OH]6), or would it be ligated to ammonium (NH4)xUy(OH)z? Could there be hot water percolating throughout a silicate core concentrating some bizarre uranium species at the silicate/water interface?

In Littlebit's Hanford scenario, the water percolates upward and evaporates. (Or does it percolate down, and concentrate the stuff at the "top of the column" - leaching away everything but the uranium)

On Charon, maybe the material percolates "upwards" but the uranium species (U3O8?) crashes out when it hits cooler water?

This just begs for a cool (and easy to do experiment with a scintillation counter) experimental model.

Just not in my lab....

-Mike

(I wonder what the forms of other likely radionucleides are? WWTD [What Would Thorium Do?])
[Potassium(40) is easy: KOH would be the preferred form and it is extremely soluble in water - it would not be able to concentrate]