On saturn's north pole there is a hexagonal cloud which does not move.
My question is: is it possible to theoretically make a hexagonal cloud on an earth-like planet? And furthermore, is it possible to "freeze" clouds in mid-air so that light doesn't pass through in certain places?

  • $\begingroup$ Welcome to WorldBuilding Lavigo! Interesting question. If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Secespitus Sep 29 '17 at 12:14
  • $\begingroup$ Yes welcome. Good question. I don't know the answer, but this might help a little: en.wikipedia.org/wiki/Saturn%27s_hexagon $\endgroup$ – Slarty Sep 29 '17 at 12:26
  • $\begingroup$ @Slarty Thank you, I have read the Wikipedia article, but I haven't come to a definitive conclusion $\endgroup$ – Lavigo Sep 29 '17 at 12:50
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    $\begingroup$ I fear that we still don't properly understand the processes involved fully, so it will be a dubly difficult but it will be interesting to see what people think $\endgroup$ – Slarty Sep 29 '17 at 14:04
  • $\begingroup$ Is there a possibility of accepting two answers? P Chapman's and will's answers are both correct, each in a different way. $\endgroup$ – Lavigo Nov 1 '17 at 9:53

Yes. Vortices on earth or anywhere, large or small can form polygons with up to 6 sides.

from http://physicsworld.com/cws/article/news/2008/may/08/polar-vortex-replicated-in-a-bucket

polygonal vortices

The linked video shows a spinning vortex in a bucket taking on polygonal shapes with up to 6 sides. https://vimeo.com/38921493

I must admit that although they demonstrate these polygonal vortices in their bucket with a rotating bottom, it remains unclear to me why the shapes form. Definitely each shape is associated with a given rotational speed. Perhaps the shapes have to do with rebounding of certain wave frequencies back into the ring to form standing waves - as seen in this excellent youtube video of a dish of water excited by sound waves.

https://www.youtube.com/watch?v=hYmx2ltHbug hexagonal standing wave in a dish

Following this reasoning, one would predict polygonal vortices would sometimes be observed on earth. And they are.

from https://www.wunderground.com/blog/24hourprof/mesovortices-in-the-eye-of-super-typhoon-haiyan.html

Curiously, these mesovortices in the eyes of very strong hurricanes sometimes take on polygonal shapes... Indeed, eyes with polygonal shapes ranging from triangular to hexagonal have been observed on high-resolution satellite imagery. Granted, the sides of the polygons sometimes don't exactly connect, but this imperfection should not dilute my message here.

hexagonal vortex in typhoon

Re: freezing a cloud in the sky.

If the circumstances that give rise to the cloud are related to an immobile topographical feature on the ground, the cloud will also be stationary or "frozen". An example of this are lenticular clouds.

lenticular cloud over table mountain https://www.cntraveler.com/stories/2015-11-10/ufo-clouds-spotted-over-cape-town-south-africa

Depicted: Table Mountain in Capetown which is apparently known for frequently hosting such clouds. You can find lots of images.

The lenticular cloud is formed by moisture-laden air hitting the mountain, being forced up, and then reaching a point where the temperature causes the moisture to condense into a cloud which sits there on or just over the mountain. I found a quote which notes such clouds are permanent in the same way a waterfall is permanent - individuals drops of moisture condense and move away but the formation appears static because it is continually replenished from new moisture.

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  • $\begingroup$ Your answer might be the most accurate, but what about the second part? $\endgroup$ – Lavigo Oct 25 '17 at 9:52
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    $\begingroup$ @Lavigo - re second part you mean freezing clouds so light doesn't pass thru? That question seemed kind of opaque to me, so to speak. I did not understand if you meant freeze them in the sky so they did not drift around - pin them over a certain spot in the ground. Or freeze them into ice (?) so that they were opaque and light did not pass thru them. Can you clarify? $\endgroup$ – Willk Oct 25 '17 at 16:00
  • $\begingroup$ Yeah, the first option. $\endgroup$ – Lavigo Oct 25 '17 at 16:03

We don't understand why Saturn has a hexagonal cloud but it is unlikely that the same mechanisms would form a cloud on an earth like planet.

However, mountains and the presence of water and other terrain features can shape cloud formation so I think it is likely that you could get Hexagonal cloud cover if you had the exact perfect terrain.

Secondly, while you cannot technically freeze a cloud (The cloud will move with the wind or tend to disperse. There are places on the earth that have cloud cover 97% of days. So if your terrain generates cloud cover as fast as it is dispersed you might get cloud cover very close to 100% of the time.

Reference: https://www.currentresults.com/Weather-Extremes/US/cloudiest.php

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  • $\begingroup$ hmph, you beat me to it! re terrain. $\endgroup$ – rebusB Sep 29 '17 at 15:39

-We dont fully understand the process of how Saturn has a hexagonal cloud.

-On Earth there is a phenomena that results in a aerial hexagonal structure called an Air Bomb. This isn't a cloud more the absence of resulting in that geometry. This does show one way a natural process can result in that shape. So theoretically it is plausible you could create such a cloud by trapping a cloud in a honeycomb of air bombs.

-Can you freeze a cloud? No, what is it called when a cloud gets frozen? SNOW

-You dont need to freeze a cloud to block out light, just make it thicker/denser.

enter image description here

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    $\begingroup$ I think OP mean freeze in location, not in temperature. $\endgroup$ – rebusB Sep 29 '17 at 15:30
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    $\begingroup$ The wp link "Air bomb" is not very enlightening. $\endgroup$ – Karl Sep 29 '17 at 20:06
  • $\begingroup$ When I said "freeze" I didn't mean that literally(notice the quotation marks), I meant make a cloud that doesn't move $\endgroup$ – Lavigo Sep 30 '17 at 16:25
  • $\begingroup$ There is nothing really that can "freeze" a storm system on Earth. Except for maybe perpetual pressure systems like the one found in the Sahara. Other planets it requires such globally chaotic weather systems. $\endgroup$ – anon Oct 2 '17 at 13:19

Typical Earth-like clouds are formed from the mixture of warm moist air with cooler air, and their movement across the globe is caused by wind forces. You could create a terrain that feeds the warm wet air from below and funnels the surrounding winds into a vortex to keep the clouds in place.

There are also clouds of smoke and dust. Once you create the dust cloud it could be corralled using winds as well, or perhaps some kind of electostatic or gravitational field local to that area of the globe.

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    $\begingroup$ I like you idea of dusk clouds. volcanic activity producing steam and / or dust could be much more consistent then solar formed cloud. $\endgroup$ – P Chapman Sep 29 '17 at 15:48

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