World Help What would the weather be? Help needed [Archive]

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The Shoeless

2020-06-14, 08:12 AM

Max_Killjoy

2020-06-14, 09:54 AM

First thing, you can offset the shell's shadow with more intense energy coming in from the star (closer, bigger, etc).

The planet's spin and atmosphere will distribute the heat to some degree, so not all of the shadowed areas will be cold desert.

My real concern would be where the openings are... if you completely cover the oceans and only expose the land, you'll likely end up with a dry atmosphere and very little precipitation on the land areas, because there will be no evaporation. There will also probably be much less life in the oceans, because there will be no photosynthesis going on there.

brian 333

2020-06-14, 11:47 AM

Too many 'ifs' in this one.

If your shell is an insulator you may trap too much heat. I would speculate the creators balanced it and there are only freezing conditions where they wanted them.

Yanagi

2020-06-14, 06:37 PM

I am currently working on a space fantasy setting for a campaign I wanted to try. These are some question for the physicists, astronomers and meteorologists and many generally smart people around here :smallredface:

The setup

Suppose a planet has been surrounded by an opaque shell with some openings the size of entire countries. This would make some regions have quite normal day/night cycles, and the borders of these regions will have parts of the year in darkness and parts with short days and long nights. Then there are the parts that will never receive outside light, which I suppose will quickly be a frozen desert.

The questions

Would there be a way for a physical shell to trap enough heat on the planet so it will not be entirely frozen?
What would the weather be in the regions with light? I suppose the heat difference between the regions with sunlight and frozen shadows would lead to violent storms. Is this correct?
Is there any way this wouldn't be totally hostile to all humanoid life? :smalleek:

I know I could just handwave these, but I would like to get a general idea what I am ignoring to make this work - might give some further ideas what magic/tech would be needed to make this world possible.

Thanks in advance for any help or feedback whatsoever :smallsmile:

Well...a very simplified comparison, but stuff under the manifold versus exposed by a gap in the manifold would be like comparing places that get less and more solar exposure because of axial tilt. Full exposure under an aperture would be more the equatorial tropics and full under the manifold would be more like the Arctic and Antarctic..

While it would depend on the precise shape of the aperture above, the uncovered regions would generally have a "brightest and warmest" spot corresponding to the location where the aperture shape plus rotation put the least limits on sunlight over the day. For example if the aperture is a circle, the center of the circle is the warmest point and also the point with the most "normal" light patterns. Daily solar load for everywhere else would be dependent on how the aperture's shape limits sunlight leaking in. In a hypothetical circular aperture, there would even distribution of solar load relative to the "bright and hot" center, but the light cycle would be radically different if one traveled along the path of rotation--west-east--versus the a line between the poles--north-south.

If you're on the polar cusps of a circular aperture, you'll share mid-day (noon) solar load conditions with the center, but experience faster drop-offs into ecliptic conditions before and after--so you'll get less solar load overall but it will be distributed normally as a ramp-up and ramp-down...artificial eclipse dawn, artificial eclipse dusk, that shortens the day.

If you're on the equatorial cusps of a circular aperture you experience an abrupt transition from darkness when planetary rotation pushes the aperture out of the way of the sun: depending on whether you're the leading or closing edge relative to rotation, "sunrise" and "sunset" happen abruptly, and the sun appears in the sky nearest to 12 o'clock high--directly overhead--than to a horizon. As such, both light and heat conditions are going to change fast--rapid heating at artificial dawn on the leading edge, rapid cooling at artificial dusk on the closing edge.

So that's preamble to keep in mind.

Without a manifold, planetary weather is a thermal loop in which hot air at the equator circulates fast, creating prevailing winds, but as it moves it eventually slows and cools as it reaches polar regions. The "weather" of the hypothetical planet is going depend on how atmospheric circulation and ocean circulation interacts with the solar load let in by the manifold. The manifold means there's less overall light and heat at the equators, so things are generally colder, but the gradient between most-exposed regions and no-exposure regions under the manifold will also form thermal loops, and those individual loops will be very important to what conditions are like. Since water also travels the thermal loop, the weather in an aperture's thermal loop will depend a great deal on how much water there is to evaporates and flow with the wind. An aperture entirely over land will be more desert-like, an aperture with some or all oceanic exposure will be more like the tropics.

And this is where I hit the limits of even guessing on the basis of anything and go into pure speculation, but...

All our assumptions about weather hinge on the big cycle of tropical heat, air, and water circulating all the way to the pole and back, and in this system, the manifold creates conditions where what starts at the equator could end near the equator. In effect, there's a theoretical point where the lightless area beyond an aperture cools enough that most moisture will condense and a lot of stuff that travels on the wind touches down. Each little pocket weather system could be on its own...persisting only through the solar load it obtains daily...with less knock-on effect because the global system is dampened. I think if you looked at this planet from space you'd see each exposed area as the center of Coriolis Effect, with clouds and "weather events" spawning at the hot points and spiraling outward. Big winds would key off of the hot points of large apertures, intermingled with whatever passed for prevailing winds from planetary rotation, so there would be covered regions that were relatively warm because they were downwind, but also covered regions that were too far away or wrongly positioned to get warm air. There'd also be a distinct pattern of moist climate apertures...where there was lots of water getting solar exposure, evaporating, and moving with the wind...and dry climate apertures where there was little water.

If you could "see" the atmosphere without the big sun-blocking manifold, there would be cloud spirals dotted where the apertures were, and a belt of sort-of warm areas in a ring around each lit area, and then full-dark areas that were alternately very cold and icy, and very cold and dry. And all of the above is not factoring for axial tilt and "seasons" within the orbit or the difference in solar loading between a pole and the equator.

How this contributes to weather: well, things would be generally colder, because any given location would be getting less solar load and any given time. Day to day there would be more temperature variance to and from high sun, especially in places where the aperture meant that there would be abrupt transitions to darkness and cooling off: this would mean a lot of rapid windspeed changes and sudden precipitation. Parts of the globe that should be very hot...the equatorial tropics...would be considerable less hot because most of the equator was covered, so there'd just generally be less hot and moist regions.

Hmm...this is getting long. Back later.

brian 333

2020-06-14, 07:21 PM

What he said.

The intensity of the sun matters. Your hot spots may be too hot to live under, or not. It may be so hot that convection warms the poles, and therefore there are no icy zones at all. Or not.

Another factor is, how insulating is your shield? Is it one way, allowing heat in but not out? Out but not in?

Another factor is, are there lights mounted on the underside to expand your agricultural regions?

What holds it up? I have a mental image of four equatorial and two polar towers of massive size. Climb the beanstalk to the giant's castle... Err, to the control rooms so you can find out what went wrong and fix it.

The Shoeless

2020-06-14, 08:11 PM

Yanagi

2020-06-14, 09:01 PM

Wow. Thanks for all the valuable feedback, people. I have a good idea how to proceed and will share the resulting setting notes if anyone is interested.

The vague idea was a planet of suitable mass and composition to become a colony for a spacefaring civilisation, but it being too close to it's star needed it to be shielded from heat and radiation. A single layered counterweighted unobtainium sky-hook/shell hybrid structure was put up to hold heat reflectors and radiation shields. Hexagonal gates in the shell could be opened or closed to allow some climate control.

Knowledge of how to control the station was lost some generations ago, and only tales of worlds beyond this world remain on a planet slipping into schizo tech.

Blabla. Needs some work. I think I will read up how cold tropics would work next :smallsmile:

Thanks again!

Well, a scifi idea would be that the shielding is supposed to have energy-collection panels and is supposed to power further devices installed in the manifold structure to make the enclosed-shell environment even more hospitable for human habitation.

So depending on how exotic/hostile you want the world to be, the devices work in some places and some don't. So if you don't want big under-manifold areas that are very hostile to life, then maybe there's artificial light-and-heat devices that still function in some places, but not in others.

ETA:

If the planet is shielded because there's to much radiation, then the areas with full exposure will be hostile to human life because they're not just too hot, but because potentially there's too much UV is getting through the atmosphere. In such a situation, fully-exposed regions of the surface would be the most hostile places for (ahem) "regular" carbon based life, while the cusp regions that got some sunlight would still have risk periods at the point of greatest solar intensity per day, but be liveable with precautions. Depending on how hot the atmosphere and surface got without the shielding, the full dark areas might not be totally freezing, but other the patterns of wind and water vapor would remain the same as what I hypothesized above: under the shielding there'd be water vapor or (even steam, depending on how hot) closest to the holes in the shielding, and then successive rings in which water condensed and fell as rain or snow.

brian 333

2020-06-14, 09:34 PM

A Legend of the Sanay People

My grandmother told me this tale when I was small like you, and she told me to remember it and tell it to the small ones so when they grow they may tell it to their small ones. Now I tell it to you. Remember it. It is true.

Long ago our people lived under a kind sun that nourished us. We were many. So many that there was no counting us all. But so many people filled the world and there was not room for all.

Then the wise elders told us there was prepared for us a garden and, if we went there, there would be room for all and each woman would have space to grow her family.

The first to come here found it so, and they sent runners back to tell all the people. And then the people came like the spring flood when sunlight first falls on the Anthen Ice Cliffs.

When all the people had abandoned the old home and gathered here then the treachery of the wise elders was revealed. They shut out the sky and only let the sun blaze or the stars freeze through the portals, and all of the people suffered cold and heat, want and illness, while the wise elders went away to live with their families in the old place, now empty of people but pleasant, warm, and full of growing things without fear of ice bears or fire cats.

But one day there will come a hero of the people and it is said he will go to the stars and make all of the sky a portal so the people can grow under the sun in the garden again. And when that is done he will find the wise elders and punish them for their crimes.

Alcore

2020-06-15, 02:41 PM

These are some question for the physicists, astronomers and meteorologists and i am none of those... I'll answer anyways...

1. Yes and no. An object that is heated radiates heat til it has no more. If the shell is made out of the right material (and with a black coloration to absorb the most light) it will radiate the heat outwards (even inwards). If the shell gets too thick it will instead act as insulation keeping the inside colder.

(Of course this largely assumes the sphere is made largely from a single material)

If the shell is technological based you can engineer the problems away. A multi layer shell with thermal generators and heating units can make the land below bearable. The first layer facing the outside should be made of something that can absorb* the most power from the sun. The next layer needs to be an insulator to contain the thermal generators, capacitors, batteries and infrastructure (they might melt otherwise if the first layer works too well). A final layer to act as a defense against a ground to orbit attacks and heating units to heat the planet below**.

2. If they got as much light as we do in a day? Should be normal. Otherwise it'll be colder, and gradually getting colder closer to the edge. Not nearly as cold as the dark areas. Tornadoes should be vary common (i think they are made of cold and warm pressure mingling)

3. With proper technology all areas are perfectly livable (or genetic engineering). The warm areas might be able to support unprotected humans (unless the holes extend from horizon to horizon it will always be colder than no shell). The darkness areas will require some artic level protection and the edge won't be livable till domiciles can withstand the storms (travel to the dark areas might also be beyond them til then).

*if shell exists outside the atmosphere it also needs to take each and every asteroid with a grin. Our sky burns up 99.99% of all space junk we get. This shell won't have that.

**unfortunately this is inefficient as hot air rises and we're starting at the top. The soil below is unlikely to be warmed enough for microbes. Though the air might reach "helmit off" conditions on the ground (artic gear still recommended for prolonged habitation).

Alcore

2020-06-15, 03:19 PM

Mmm! Before i forget...

Weather!

Should be mild everywhere that is in darkness. Our weather is made (in the most general of terms) from planet rotation and the heating and cooling of the air. Weather is my weak point on this discussion.

There should be no rain or snowing going on. No water vapor from the sun. A storm might roll out from the warm ares but most of the darkness area will be dry, calm and dark.

Now... if the shell is trying to pump hot air down there is going to be wind. Strong, horrible wind as hot and cold air mingles. Still no rain unless the ground water reaches evaporation temperatures.

(Both posts assume earth. I know you made a second post. My time runs short. I'll be back)

The Shoeless

2020-06-18, 11:37 AM

Well, a scifi idea would be that the shielding is supposed to have energy-collection panels and is supposed to power further devices installed in the manifold structure to make the enclosed-shell environment even more hospitable for human habitation.

So depending on how exotic/hostile you want the world to be, the devices work in some places and some don't. So if you don't want big under-manifold areas that are very hostile to life, then maybe there's artificial light-and-heat devices that still function in some places, but not in others.

ETA:

If the planet is shielded because there's to much radiation, then the areas with full exposure will be hostile to human life because they're not just too hot, but because potentially there's too much UV is getting through the atmosphere. In such a situation, fully-exposed regions of the surface would be the most hostile places for (ahem) "regular" carbon based life, while the cusp regions that got some sunlight would still have risk periods at the point of greatest solar intensity per day, but be liveable with precautions. Depending on how hot the atmosphere and surface got without the shielding, the full dark areas might not be totally freezing, but other the patterns of wind and water vapor would remain the same as what I hypothesized above: under the shielding there'd be water vapor or (even steam, depending on how hot) closest to the holes in the shielding, and then successive rings in which water condensed and fell as rain or snow.

You are absolutely right. The shell worlds climate could be controlled by the shell. This will allow for much more biome diversity. However, this makes it a lot more important to see what would happen if the weather control system would not work on those places.

The burning light is a very nice flavour. There could be whole countries fearing the light more than the dark, as light destroys everything it touches... Could be a nice alien feeling for some cultures.

A Legend of the Sanay People

My grandmother told me this tale when I was small like you, and she told me to remember it and tell it to the small ones so when they grow they may tell it to their small ones. Now I tell it to you. Remember it. It is true.

Long ago our people lived under a kind sun that nourished us. We were many. So many that there was no counting us all. But so many people filled the world and there was not room for all.

Then the wise elders told us there was prepared for us a garden and, if we went there, there would be room for all and each woman would have space to grow her family.

The first to come here found it so, and they sent runners back to tell all the people. And then the people came like the spring flood when sunlight first falls on the Anthen Ice Cliffs.

When all the people had abandoned the old home and gathered here then the treachery of the wise elders was revealed. They shut out the sky and only let the sun blaze or the stars freeze through the portals, and all of the people suffered cold and heat, want and illness, while the wise elders went away to live with their families in the old place, now empty of people but pleasant, warm, and full of growing things without fear of ice bears or fire cats.

But one day there will come a hero of the people and it is said he will go to the stars and make all of the sky a portal so the people can grow under the sun in the garden again. And when that is done he will find the wise elders and punish them for their crimes.

Nice. The idea of myths building on forgotten or superficial knowledge could build a common core belief. The keepers of old could be universally known, under slightly different names, as Gods, Heros, or even Devils.

i am none of those... I'll answer anyways...

Don't sell yourself short. Why would you say you are not smart? :smallsmile:

*if shell exists outside the atmosphere it also needs to take each and every asteroid with a grin. Our sky burns up 99.99% of all space junk we get. This shell won't have that.

**unfortunately this is inefficient as hot air rises and we're starting at the top. The soil below is unlikely to be warmed enough for microbes. Though the air might reach "helmit off" conditions on the ground (artic gear still recommended for prolonged habitation).

Good points, and something to have a good thinking session about.

Should be mild everywhere that is in darkness. Our weather is made (in the most general of terms) from planet rotation and the heating and cooling of the air. Weather is my weak point on this discussion.

There should be no rain or snowing going on. No water vapor from the sun. A storm might roll out from the warm ares but most of the darkness area will be dry, calm and dark.

Now... if the shell is trying to pump hot air down there is going to be wind. Strong, horrible wind as hot and cold air mingles. Still no rain unless the ground water reaches evaporation temperatures.

A zone with no light and no energy (and likely no life) would have a lot of similarities with a giant sensory deprivation tank (especially if we fiddle with the gravity a bit :smallamused:). Slap a ominous, slightly physics-based name on it and players will fear it.

"The Eigengrau Zone"

Yanagi

2020-06-18, 01:13 PM

A malfunctioning shield also facilitates strangeness, such that you can go beyond normal biome distinctions.

So there could hexagonal plates that only let through specific sections of the visible spectrum, so "day" is yellow-green and "night" is red.

Or plates that don't emit enough light to illuminate the surface, but glowed or pulsed enough to be visible from the surface. The become the equivalent of stars and constellations for surface cultures: a way of navigating. Indeed, navigation by plate phenomena would be extremely useful and convenient.

Or a plate that's stuck just slightly open, so there's this crescent of intense heat and light that's blinding to look at and shines down on a body of water, creating steam that spread out and becomes water vapor, so there's a whole sea that's under fog conditions most of the time.

There could be the same kind of malfunction with thermal controls

And it's doesn't have to just be light/heat controls up there on the shield.

For example, the shield has some way of tractoring objects entered the gravity well--with a eye towards resources like watery comets and metallic asteroids--so there's a region where tons of strange-shaped metallic meteorites have been diligently set, gently, on the planets surface, like an especially unreal rock garden.

Or there could be a surface region that's been blasted by a defense device--a kinetic weapon like a rod from god, or a point defense system that's meant to face outward, or a terraforming laser whose targeting's gone off and is now etching a desert with patterns of fused glass.

brian 333

2020-06-18, 01:42 PM

A malfunctioning shield also facilitates strangeness, such that you can go beyond normal biome distinctions.

So there could hexagonal plates that only let through specific sections of the visible spectrum, so "day" is yellow-green and "night" is red.

Or plates that don't emit enough light to illuminate the surface, but glowed or pulsed enough to be visible from the surface. The become the equivalent of stars and constellations for surface cultures: a way of navigating. Indeed, navigation by plate phenomena would be extremely useful and convenient.

Or a plate that's stuck just slightly open, so there's this crescent of intense heat and light that's blinding to look at and shines down on a body of water, creating steam that spread out and becomes water vapor, so there's a whole sea that's under fog conditions most of the time.

There could be the same kind of malfunction with thermal controls

And it's doesn't have to just be light/heat controls up there on the shield.

For example, the shield has some way of tractoring objects entered the gravity well--with a eye towards resources like water comets metal--so there's a region where tons of strange-shaped metallic meteorites have been diligently set, gently, on the planets surface, like an especially unreal rock garden.

Or there could be a surface region that's been blasted by a defense device--a kinetic weapon like a rod from god, or a point defense system that's meant to face outward, or a terraforming laser whose targeting's gone off and is now etching a desert with patterns of fused glass.

I like all of these!

What if the 'portals' are simply regular hexagons stuck in the open position?
Or ones broken by meteorites when the defensive tractor/repulsor was broken?

Shards of hexagon material:
Sharper than any metal
Harder than any stone
Cannot be filed, drilled, melted, or cracked
Venerated, feared, used as tools, or forbidden as holy/unholy artifacts

Alcore

2020-06-18, 09:44 PM

Don't sell yourself short. Why would you say you are not smart? :smallsmile: if you notice carefully i did not quote the part about general smartness ;)

Alright. Digested second post. Slept on it and reflected on what i had and it still sounds good.

The vague idea was a planet of suitable mass and composition to become a colony for a spacefaring civilisation, but it being too close to it's star (1)needed it to be shielded from heat and radiation. A (2)single layered counterweighted unobtainium sky-hook/shell hybrid structure was put up to hold heat reflectors and radiation shields. Hexagonal gates in the shell could be opened or closed to allow some climate control.

1. I honestly think the open areas will be unlivable to humans. The more complex a creature is the lower its threshold for enduring radiation. So long as the temperature doesn't get too bad and they get the nutrients they need plants might not be bothered by it. By contrast a human might grow cancer, tumors and die if radiation gets too high. This can take days, weeks, months or even years. If radiation gets way too high you won't have to worry about cancer or tumors; radiation is heat and you'll cook as if in a microwave.

(Though if it gets too hot it'll turn into a hellscape)

So my thinking is they live in subterranean habitats along the rim and use tunnels to get to their farms. Said farmers can wear vacc suits (like the kind astronauts wear; inferior to the planet but is as necessary to keep oxygen in as radiation out) and the plants still need decontamination procedures. Unless the process is perfect everyone will be mildly poisoned.

Depending on how gritty or fanciful your sci fi is they are either dying en mass or drifting into humanoid territory as they mutate into a new human offshoot that could live unaided.

2. Don't quite know what all that is... but it sounds awesome! You quoted my post so i won't quote the space junk part and continue. Since what we have is a dyson sphere we have a number of options available. If temperature is too high gun emplacements won't work (energy will melt from the combined heat of both the star and themselves. Standard ballistics will ignite/explode damaging the sphere. A mass driver will work but after collision with an incoming asteroid it might actually bounce back at the station as its own asteroid) but shielding can.

Proper energy shields from star trek are possible at this level but power might be too limited to surround the whole thing. I'm thinking deflectors. You magnetize the outer hull (which means the teck doing the work can be embedded safely away from the heat). Asteroids coming in at an angle can be deflected back into space and those coming head on will lose velocity and impact with less force.

(Of course this assumes i am building for the least amount of upkeep and not most effective/efficient method that might require a tech base behind it to keep it functional. Since it's been generations I'm thinking low tech where possible with as many self sufficient systems as possible.)

Edit: those are my design considerations at least. What about your builders? Was the lost tech base part of some plan? Was it built with the idea they might not be around to keep fixing it? Did ancient government or corporate policies skimp on construction?