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aphilsphan t1_jc2znif wrote

Reply to comment by Zondartul in Is there a type of precipitation that exists on other planets but not ours? Or theoretical precipitation that doesn’t happen here? by ButIHateTheTaste

CO2 deposition would occur at the Martian poles. The dry ice sublimes when the temperature gets high enough and deposits again when it gets colder. This drives a lot of the changes in atmospheric pressure.

I’d like to see a planet with enough pressure and the right temperature range for CO2 to be a liquid. I’m sure there are ammonia dominated planets.

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OlympusMons94 t1_jc3jq6v wrote

CO2 near Venus' surface is a supercritical fluid, which is neither gas nor liquid, but has properties of both. At present, the CO2 is more gas-like, but in the past Venus' surface pressure may have been even higher, possibly enough to support a more liquid-like supercritical CO2 (Bolmatov et al., 2014).

There is also supercritical CO2 within Earth's crust. Supercritical and even actual liquid CO2 are released by hydrothermal vents on the sea floor.

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zekromNLR t1_jchro7m wrote

If Venus were cooled to a sufficiently cold temperature (to achieve that, most of the sunlight that hits it would need to be blocked), most of its supercritical CO2 atmosphere would condense out into an ocean of liquid CO2, that would then freeze over into a crust of dry ice hundreds of meters thick.

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