A shirtsleeve world without rain?

[robject]

Is there any shirtsleeve planetary setup where there may be water, but despite that, there is no rain?

Like Arrakis, where there's oodles of water but it's all trapped by sandtrout.

Can a desert world yet have extensive ice caps and aquifers amounting to oodles and oodles of water?

Maybe a tundric desert world?

 

[whulorigan]

Is there any shirtsleeve planetary setup where there may be water, but despite that, there is no rain?

Like Arrakis, where there's oodles of water but it's all trapped by sandtrout.

Can a desert world yet have extensive ice caps and aquifers amounting to oodles and oodles of water?

Maybe a tundric desert world?

What about the opposite - a world with a torrid enough climate that all of the water is trapped as vapor or condensate in the upper atmosphere, but rain never reaches the ground. I don't know if the correct set of temperature and pressure conditions would constitute a "shirt-sleeve environment", however.

Basically on Earth, the temperature and pressure conditions lie close to the triple-point of water, where all three states (solid/liquid/gas) can coexist simultaneously with only relatively small fluctuations of temperature or pressure. I do not know if you could move the combined temperature/pressure conditions away from the triple point sufficiently far enough to preclude condensation from vapor without ruining the "shirtsleeve" environment, however.

What if all of the water is trapped in the crust in the form of hydrates of some salt or other crystalline substance?

 

[whartung]

Does it have to be the entire world, or can it just be a zone.

An area with under ground aquifers pumping springs to fill lakes etc. but the evaporation gets carried off to Somewhere Else and never gets a chance to accumulate and actually rain.

 

[robject]

Does it have to be the entire world, or can it just be a zone.

An area with under ground aquifers pumping springs to fill lakes etc. but the evaporation gets carried off to Somewhere Else and never gets a chance to accumulate and actually rain.

If a zone had this sort of setup, how big of a region would it apply to? A hundred kilometers' radius or so?

Or, perhaps it would require a kind of "trade winds" setup where most of the moisture gets trapped when it comes up against a very high mountain range? Creating a rain shadow?

I think there are many regional explanations for the (relative) lack of rain.

No rain whatsoever is much trickier in my mind.

I keep coming back to Arrakis, which might marginally be considered "shirtsleeve".

 

[robject]

What about

[...] a world with a torrid enough climate that all of the water is trapped as vapor or condensate in the upper atmosphere, but rain never reaches the ground. [...]

I do not know if you could move the combined temperature/pressure conditions away from the triple point sufficiently far enough to preclude condensation from vapor without ruining the "shirtsleeve" environment, however.

What if all of the water is trapped in the crust in the form of hydrates of some salt or other crystalline substance?

Good suggestions. Very tricky, isn't it. I keep coming back to sandtrout.

 

[robject]

Looks like the surface of such a world, even if the atmosphere makes it shirtsleeve, is still going to be relatively inhospitable.

A bootstrap colony (left there with no possessions but their wits) would doubtless have a tough time surviving. Mortality would be dreadful. They'd have to be awfully well-organized and smart.

 

[whulorigan]

Looks like the surface of such a world, even if the atmosphere makes it shirtsleeve, is still going to be relatively inhospitable.

A bootstrap colony (left there with no possessions but their wits) would doubtless have a tough time surviving. Mortality would be dreadful. They'd have to be awfully well-organized and smart.

Could they survive in an underground environment (possibly venturing onto the surface for short periods for particular needs)?

 

[aramis]

What about the opposite - a world with a torrid enough climate that all of the water is trapped as vapor or condensate in the upper atmosphere, but rain never reaches the ground. I don't know if the correct set of temperature and pressure conditions would constitute a "shirt-sleeve environment", however.

Basically on Earth, the temperature and pressure conditions lie close to the triple-point of water, where all three states (solid/liquid/gas) can coexist simultaneously with only relatively small fluctuations of temperature or pressure. I do not know if you could move the combined temperature/pressure conditions away from the triple point sufficiently far enough to preclude condensation from vapor without ruining the "shirtsleeve" environment, however.

What if all of the water is trapped in the crust in the form of hydrates of some salt or other crystalline substance?

The problem with airborne moisture is that there is a tendency towards acidification. Water likes to form and/or trap acids. Water is also, in and of itself, stupidly highly reactive. Upper atmospheric water gets popped from 2( H2O) -> H2 + 2(O) -> H2 + O2, with the occasional H2 -> He + H by proton capture.... and H and He both exit happily...they're below minimum molecular mass retained by even size A worlds.

 

[Enoki]

If you look at the Atacama Desert on Earth, it never gets rain or pretty close to that. Yet, in many parts of it you can dig down a foot or two and hit moisture in the soil.

You can also get moisture in the form of fog (clouds in ground contact) and mists. So, maybe you have a planet that is shrouded in fog 100% of the time... Nice spooky setting there when you combine it with perpetual twilight or night... :devil:

 

[flykiller]

how 'bout an ice world outside the hz? 100% surface water, all frozen. antarctica is the driest place on earth.

 

[atpollard]

Let's take a run at the problem from the other direction. Rain requires lots of atmospheric water. Surface water requires an impermeable layer to stop it from moving down through the soil. So what about a world with a moderate hydrographic to begin with, say 30 percent, and very little variation in topography, something like the Great Plains of North America. Lots of lakes and rivers, but no large oceans.

Now let's cover this terrain with a kilometer of pea gravel like soil. All those lakes and rivers are still there and will still flow, but the rain landing on the surface will soak into the ground almost instantly. The rivers and lakes are part of the aquifer system. Protected from the sun, there will be little evaporation, so the rain cycle will quickly slow and nearly stop. Now you might have an ecosystem like Sonora Desert where it is barren waste most of the year, except for a very rare rainfall when all the plants bloom for a short period.

My colony only needs to sink a deep well to extract water to maintain a farm in the desert.

 

[Enoki]

Another type of world I've actually done that fits is the swamp. Here you have a 100% hydrosphere (or close to it) but the water is never deeper than a few meters. The world is completely, or nearly so, vegetated. You now have a primordial world. All you need to prevent or not have rain is some mechanism that limits evaporation.
One way to do that is the surface of this swamp is covered in a layer of thick organic "slime." The slime prevents evaporation of moisture. Add in that the rest of the vegetation readily reabsorbs moisture from the air and you have very low humidity preventing cloud formation and rain.

 

[Timerover51]

Is there any shirtsleeve planetary setup where there may be water, but despite that, there is no rain?

Like Arrakis, where there's oodles of water but it's all trapped by sandtrout.

One thing that has always bugged me about Arrakis, and why I never really liked the series is, where does the oxygen for life come from?

Can a desert world yet have extensive ice caps and aquifers amounting to oodles and oodles of water?

Mars may have that, but it is not a shirt-sleeve environment. The problem is how do you get the water from the ice caps to the aquifers.

Maybe a tundric desert world?

What is a "tundric" world? I find "tundra" worlds in T5.09, but "tundric" comes up a blank.

 

[Timerover51]

Let's take a run at the problem from the other direction. Rain requires lots of atmospheric water. Surface water requires an impermeable layer to stop it from moving down through the soil. So what about a world with a moderate hydrographic to begin with, say 30 percent, and very little variation in topography, something like the Great Plains of North America. Lots of lakes and rivers, but no large oceans.

Now let's cover this terrain with a kilometer of pea gravel like soil. All those lakes and rivers are still there and will still flow, but the rain landing on the surface will soak into the ground almost instantly. The rivers and lakes are part of the aquifer system. Protected from the sun, there will be little evaporation, so the rain cycle will quickly slow and nearly stop. Now you might have an ecosystem like Sonora Desert where it is barren waste most of the year, except for a very rare rainfall when all the plants bloom for a short period.

My colony only needs to sink a deep well to extract water to maintain a farm in the desert.

How do you get the vegetation to have sufficient water to produce oxygen via photosynthesis? Without the rest of the Earth's vegetation producing oxygen, you have no animal life to produce carbon dioxide. Also, the world would have to be dead tectonically, otherwise, you would have varied elevations, with differing thicknesses of your pea-gravel, and in some cases, no pea-gravel.

 

[Timerover51]

If you look at the Atacama Desert on Earth, it never gets rain or pretty close to that. Yet, in many parts of it you can dig down a foot or two and hit moisture in the soil.

You can also get moisture in the form of fog (clouds in ground contact) and mists. So, maybe you have a planet that is shrouded in fog 100% of the time... Nice spooky setting there when you combine it with perpetual twilight or night... :devil:

That is due to it being quite close to the equator with the cold Humboldt Current flowing off-shore, with the prevailing winds blowing from the west, off of the cold current, then being heated by the sun, which drastically reduces the humidity of the air. The moisture in the air continues to travel east, and rises when it hits the Andes mountains, where it then produces rain and fog.

 

[shaunhilburn]

Is there any shirtsleeve planetary setup where there may be water, but despite that, there is no rain?

Like Arrakis, where there's oodles of water but it's all trapped by sandtrout.

Can a desert world yet have extensive ice caps and aquifers amounting to oodles and oodles of water?

Maybe a tundric desert world?

Desert worlds aren't necessarily completely dessicated. Consider that North America is 4.76% of Earth's surface. An equivalent sized arid world with an ocean the size of North America is 95.24% barren; Hydro digit 0 and would still qualify as a desert world.

One triangle of the icosahedral map is 1/20th = 5% of the surface; about 24.4 hexagons. Desert worlds can have seas filling less than than this area.

 

[Whipsnade]

If you look at the Atacama Desert on Earth, it never gets rain or pretty close to that. Yet, in many parts of it you can dig down a foot or two and hit moisture in the soil.

Beat me to it! Atacama has been very dry for a very long time too. Something like 100 or 200 million years, IIRC.

Compared to Earth's entire surface area, the Atacama is relatively tiny. Maybe 1000km long, 100K sq-km in size, and it couldn't get much bigger. While it exists mostly due to a double rain shadow by the two mountain ranges, I've read that it couldn't extend past certain latitudes anyway due to jet streams that would drag weather systems in regardless of the mountain ranges.

The cool Humboldt current offshore plays a role too, both limiting the amount of moisture coming from the Pacific while also producing the fogs you mention.

Transferring the Atacama into the OTU to create Robject's "rain-free" planet would result in a world that is mostly ocean because an Atacama-like desert can't be that big. Place the necessary mountain ranges, ocean currents, and rain shadows in the necessary locations and - VOILA - Bone Dry III.

As for oxygen, one word: phytoplankton

Photosynthesis just doesn't happen on land.

 

[aramis]

An "Eyeball Earth" could have the hab zone much like the Central Alaska Desert... the glacial melt runs sunward, while the vapor melts and flows spaceward. a large band of rain-free wetlands tapering off to grasslands, then to hotside deserts....