Suppose, Venus becomes tidally locked. Will its dark side cool enough so that the CO2 from atmosphere to precipitate in liquid form to make an ocean?
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1$\begingroup$ Planetology is earth science. $\endgroup$– AnixxMay 17, 2021 at 15:45
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$\begingroup$ I just noticed an Answer on Meta Earth Sciences, your question is on-topic I was just suspicious about this one because of the Name of this site. $\endgroup$– TardyMay 17, 2021 at 15:49
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1$\begingroup$ The question should easily fit earthscience.se as the same physics, chemistry and geological principles as on Earth are applicable to the other solar system objects. $\endgroup$– AtmosphericPrisonEscapeMay 18, 2021 at 1:02
1 Answer
While Venus is not tidally locked to the sun, it rotates slow enough that you might as well consider it tidally locked.
However you have to disentangle the slow rotation from the superrotating atmospheric motion. The fast atmospheric rotation (as reaction of the atmospheric gases to the intense solar radiation) redistributes heat very efficiently in the upper atmosphere.
In the lower atmosphere, no significant winds are observed, but the atmosphere has a large density, which through heat conduction again makes redistribution of heat efficient.
All in all, Venus' atmosphere has therefore a horizontally uniform temperature. Said differently, next to no dayside-nightside temperature gradients exist. Nothing will precipitate.
Furthermore the $CO_2$ at the surface is superfluid due to the intense pressure, and this state doesn't seem to form droplets, it IS a sort of highly-viscous $CO_2 $-ocean.
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$\begingroup$ Would not superrotation disappear if the planet was locked? $\endgroup$– AnixxMay 18, 2021 at 1:23
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$\begingroup$ @Anixx: There is nothing magic in a tidally locked state compared to the extremely slowly rotating state that Venus is in now. So for the purposes of atmospheric dynamics the planet is non-rotating, the same as it would be essentially non-rotating in a tidally locked state. Therefore the answer is, no, as it already has superrotation. $\endgroup$ May 18, 2021 at 1:27
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$\begingroup$ @Anixx: Is there a physical reason why you would presume superrotation to disappear? $\endgroup$ May 18, 2021 at 1:28
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$\begingroup$ Where the supertotation gets angular momentum? $\endgroup$– AnixxMay 18, 2021 at 1:30
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$\begingroup$ @Anixx: Initially, always from the dayside pressure-gradients. Just as with any wind. The wind then equilibrates the pressure gradients that created it. However in details this story for Venus is very much more complex, have a look here for example, science.sciencemag.org/content/368/6489/405 $\endgroup$ May 18, 2021 at 1:36