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So my planet is tidally locked, it constantly faces its star like the moon faces Earth. One side is completely frozen, the other is burning hot. There is an atmosphere that allows life, and people live on a thin ring that is at the right temperature to live.

I don't think life can emerge in that pattern, so assume the planet was once fit to allow life, and some undocumented event happened, making the planet stop spinning ("tidally locked" is more precise). Enough time has passed for the climate to stabilize completely (I'm talking in million years). The current population is descended from colonists who settled on the planet after the climate had stabilised.

How would the winds and oceans be affected? [edit: the part of the question about the winds has an answer] Can a complete water cycle function on such a planet ? Winds are greatly influenced by oceans, so how would they behave ?

Are there other things that would behave in a special way ?

Note : I didn't know abut the term "tidally locked", thank you. That's what I meant (I also mixed up "rotation" and "revolution"). The part about the wind currents has already been asked.

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  • $\begingroup$ Your planete is still spinning, just far slower than a non tiddaly locked one. And btw the event you're talking about slowing it is happening right now on earth, each day is infinitesimaly shorter than the previous one due to the sun tidal force on us $\endgroup$
    – Sefa
    Commented Jan 26, 2017 at 14:10
  • $\begingroup$ This question is already asked here: worldbuilding.stackexchange.com/questions/57974/… Unfortunately, it really has no answers. Still, this question is a duplicate. $\endgroup$
    – kingledion
    Commented Jan 26, 2017 at 14:11
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    $\begingroup$ Possible duplicate of Circulation patterns on a tidally-locked binary planet $\endgroup$
    – kingledion
    Commented Jan 26, 2017 at 14:11
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    $\begingroup$ Actually, I'm wrong it is a duplicate of this one: worldbuilding.stackexchange.com/questions/4850/… I'll edit my close vote in 41 mins when I can. $\endgroup$
    – kingledion
    Commented Jan 26, 2017 at 14:12
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    $\begingroup$ The linked questions are purely about the wind patterns, while this question asks about both wind patterns and water cycles. Because answers to those questions do not adequately cover the entirety of this question, I refute that this is a duplicate. $\endgroup$
    – Frostfyre
    Commented Jan 26, 2017 at 14:39

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So wind wise, you'd have Hadley cells that extend around the planet. Basically hot dry air on the sunward side would cause the air to heat up, rise, and make a low pressure area. Meanwhile on the far side you'd have air cooling down, falling, and causing a high pressure area.
Because the air will then move from high pressure to low pressure, it will flow back around the planet toward the hot side, taking moisture with it. These hot and cold fronts will mix most around the terminator, causing storms that will bring rain and clouds, which will help cut down on the insolation a bit.
This will probably lead to what is called a "hot eyeball earth", so snow and ice on the back side and around the terminator, leading to a well watered band further into the light, with a hot dry pupal right at the center where the clouds don't quite make it. The night side, while cold, might not be completely uninhabitable because of the constant stream of warm air from the light side.

As for water cycle, that depends a lot on your geography, but mostly it is going to fall as rain on the light side, and then evaporate and be carried back to the night side, where it will fall as snow, then sublimate and be carried back to the light side.

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  • $\begingroup$ Thanks, very interesting. I don't understand the part about sublimation though. How would water be carried back to the light side ? $\endgroup$
    – Teleporting Goat
    Commented Jan 26, 2017 at 16:03
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    $\begingroup$ If you take a ice cube or whatever and leave it out in the open in your freezer, over time it'll get smaller. If you had a fan blowing over it, even if the temperature stays below freezing, it'll get smaller faster. Sublimation is when a solid transitions to a gas without becoming a liquid first. The constant flow of warmer air from the day side will pick up moisture this way, and carry it back to the day side. The less moisture that goes back, the hotter the air will get, and the more moisture it'll pick up when it cycles to the cold side, so you'd have an ebb and flow. $\endgroup$
    – AndyD273
    Commented Jan 26, 2017 at 18:01
  • $\begingroup$ @AndyD273, so there's a "band" around the planet where there is always stormy weather? And on either side very warm and very cold. Wow. That would definitely impact life and societies. $\endgroup$
    – Len
    Commented Jan 25, 2018 at 19:57
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Aye to follow up what @szczerzo kly said, pretty much nothing bolted to bedrock would fly off the planet so, basically everything would be gone. which includes valuable aspects to life such as water. It is though not clear if we would lose magnetism or not, however evidence does indicate that the poles would lose power over time due to a lack of charging. Life on a planet would also be hard to maintain but not impossible. Wind would also change drastically.

Not sure that a planet in this state can stabilize completely so that life can return wide spread. You will be limited to zones in which climate can still be suitable for life. Depending on how cold the other side is, life probably would be hard to maintain. With a lack of light, creatures, if they can survive, will more than likely go blind through evolution in place of more sonar related enhancements. They will also, have a hard time going between sides as the sun would almost instantly scorch skin that lacks any pigment. Their bodies would have adapted to temperatures so cold that even what would be considered "cold" on the other side would more than likely provide heat strokes.

I know you didn't specifically ask about life but since you mentioned the planet being stable enough for life again I figured to chime in about both aspects of the wind/water and life. All in all, it would be a very harsh environment even with stability.

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A) the moon rotates. It's called synchronous rotation
B) the planet could stop rotating due to some external event but that event would be the problem to the life on the planet rather than the lack of spin.
Like the fact that anything not bolted to the planet would go flying in the atmosphere (assuming that the stop force was "magical" and not some bomb or space rock)
C) the magnetic force for planet would vanquish and all things protecting planet from space radiation would be gone
D) the climate would not stabilize, it would just change. The major winds would be generated by the fact that half of the planet is super hot and other is super cold.

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  • $\begingroup$ A) That's what I meant, I didn't know the exact term. B) I don't care about life then. The event probably killed most of the life, and the rest couldn't adapt the the new climate fast enough. I edited my question, the stable state I'm talking about was reached several million years after the event. C) Vanquish what ? Did you mean vanish ? That's interesting, I didn't know it was linked to rotation. D) again, imagine waiting long enough (however long that takes) for the climate to stabilize. $\endgroup$
    – Teleporting Goat
    Commented Jan 26, 2017 at 14:33
  • $\begingroup$ @TeleportingGoat "Tidally locked" is the correct term. $\endgroup$
    – IT Bear
    Commented Jan 26, 2017 at 22:43

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