Making a gas torus setting make sense

[Trekkin]

I'm trying to do something a bit silly again: building a setting largely in microgravity (with air) without explicit recourse to handwaving. This time around, I'm looking at implementing a gas torus, a la The Integral Trees, albeit with numbers more like these.

I'm fine with chalking the formation of the system and its population by sentient life up to divine caprice, but once it's together it'd be ideal if it would stay together at least partially according to physics rather than magic.

As far as my childishly incomplete grasp of orbital mechanics can determine, the numbers agree with themselves, but I don't know how to determine some rather important things, like the dimensions of the potential wells at the L4 and L5 lagrangian points. These are important, because part of the plan is to put enough rock/metal there to allow the industry usually associated with high fantasy -- and dwarven-built Reagan cylinders.

So, if we assume that the system as described in the link is suddenly instantiated by The Powers That Be (TPTB) snapping their fingers:

1. Will it hold together?

1.5. How can I calculate the air pressure at a given point in the ring?

2. How much mass over how much volume can stably hang out in the L4 and L5 Lagrangian points?

3. How much mass can go elsewhere? Can I have debris just sort of scattered around, stably over a few hundred years?

I know it's kind of inconsistent to have TPTB just get mad at mortals, throw the system together, messily flay the crust off an Earth-sized planet and dump the shards in the ring life and all, and then to turn physics back on and ask that everything stay more or less where it's put (or clump up) , but it's about the bizarre level of hardness my group likes.

So can it work?

[Malachi Lemont]

I have no idea whether it's physically possible, but it's sounds like a great idea to explore! I love the thought of living in a floating smoke ring. Are there platforms for people to stand on, since there's no ground? Who built the platforms? What happens if you fall off? I'm very intrigued.

[Trekkin]

I have no idea whether it's physically possible, but it's sounds like a great idea to explore! I love the thought of living in a floating smoke ring. Are there platforms for people to stand on, since there's no ground? Who built the platforms? What happens if you fall off? I'm very intrigued.

It's a bit difficult to stand, unless you're next to a massive object or spinning to create pseudogravity.

If my numbers are right, falling isn't actually that traumatic. Unlike in space, there is something to stop you, sort of: drag. Things eventually slow down to the same speed as the surrounding air and just orbit like everything else. Now, what that speed is varies with distance from the primary (and this is a great aid to travel, since if you can travel radially you can also travel along the ring) so if you "fall" far enough away, you'll keep separating rapidly from whatever you fell from.

[Rakaydos]

Huh. Now I want to see this with a "Boy and his tank" style heavy metals "Elemental plane of Earth" (where after the nova a planet condenced from the heavy elements that didnt get blown away, in layers by melting point, from the tungstin shell (first to cool) down to the still molten Mercury core. The Gold layer is, if not exactly habitable, at least non toxic. :p)

Europa or the speculations about Glisse could be a good example of Elemental Water- Ice above, lethal pressure below. Not sure about Fire- that's a hard one to make semi-habitable.

[Lpaulb116]

I haven't read this yet, but...
Gassy Donuts!!!

[Lpaulb116]

Now that I've read through it. It looks good. Some questions (that you might've answered in your link to the numbers.
1. What is it made of?
2. What is its mass?
3. Where is its star?
4. How big is the star?
5. Does the torus rotate?

[Admiral Squish]

Not sure about Fire- that's a hard one to make semi-habitable.

I don't think fire would be habitable, honestly, not by anything not evolved to survive there.
I once created a planet that could serve as a baseline, though. I'm not as... mathematically inclined as some of you, so I can't cite numbers and distances and the like.

Spoiler: Gehenna

Show

A large, rocky planet, about twice the size of earth. Orbiting very close to an O-class star. The planet is tidally locked to the parent star, but rotates very quickly perpendicular to the orbit, which gives it a strong magnetic field to preserve it's atmosphere of oxygen and sulphurfic acid. Intense heat and radiation heat the planet to the point that the vast majority of it's surface is molten. the immense size of the parent star means three-quarters of the planet directly receives the sun's heat. There's a small area of shadow on the far side from the sun, where the molten ground actually solidifies into a floating continent roughly the size of Australia, dominated by an enormous, permanent hurricane and pools of acid. The temperature differences change the consistency and makeup of the magma in different areas.
Life there is silicon-based, mostly due to the resistance of silicon bonds to acid. There are plant analogues that absorb molten glass from the magma and release oxygen, which is either sublimated into the magma flow and circulated via convection currents, or released into the atmosphere. Animals there are mostly 'aquatic' 'swimming' through the magma(it's actually a distinct movement since magma doesn't flow as easily as water, somewhere between swimming and burrowing). They absorb oxygen from the magma and release molten glass. Different creatures inhabit different magma consistencies and different pressure zones. Mostly, they navigate via echolocation, as the opaque magma prevents visual navigation of the medium. There are a few airborne creatures, but the harsh and foreign conditions of the shadow continent leave it mostly devoid of life.

[Trekkin]

Now that I've read through it. It looks good. Some questions (that you might've answered in your link to the numbers.
1. What is it made of?
2. What is its mass?
3. Where is its star?
4. How big is the star?
5. Does the torus rotate?

Hey, people are still responding. That'll teach me not to check my old threads. Anyway.

1. The torus? I'm assuming Earth's atmosphere, mostly. 4/5ths nitrogen, the rest oxygen, some other stuff besides. Exact gas composition can vary, but if it's breathable by humans that's kind of the point.

2. I don't know. I can't calculate the density gradient for the torus. The gas giant core, which is the second mass in the system, is about 1 Earth mass.

3. One star's in the middle of the torus, which is 4 million kilometers in radius; this is the older neutron star that's the gravity source for the system. The other one is 250 million kilometers away.

4. The inner star is 1.5 solar masses (the link has the mass a little low for a neutron star, I'm afraid.) The outer star is pretty much the Sun.

5. Yes, it does; the whole thing is in orbit, 32 hours per rotation.

Mostly, I just want it to hold together so I can let the various forces inside exploit orbital mechanics as a sort of spelljammer lite, only with very light ships with very fanciful propellers. The edges move at a different speed than the middle, so holding to the edge of the ring vastly speeds travel around it.

[Everyl]

Huh. Now I want to see this with a "Boy and his tank" style heavy metals "Elemental plane of Earth" (where after the nova a planet condenced from the heavy elements that didnt get blown away, in layers by melting point, from the tungstin shell (first to cool) down to the still molten Mercury core. The Gold layer is, if not exactly habitable, at least non toxic. :p)

Europa or the speculations about Glisse could be a good example of Elemental Water- Ice above, lethal pressure below. Not sure about Fire- that's a hard one to make semi-habitable.

I've read a book series that had element-themed habitable worlds. Fire was a thin stone shell around a central mini-star - basically a small Dyson sphere. The interior surface was a vast jungle with no night. I don't recall if gravity was ever explained.

[lunar2]

this reminds me of a short story i read one time... and on doing the research i see that story is part of the series that makes up the novel you referred to. you have my blessing, i loved that setting.

[Trekkin]

this reminds me of a short story i read one time... and on doing the research i see that story is part of the series that makes up the novel you referred to. you have my blessing, i loved that setting.

Unfortunately, Niven's stories are less helpful than I'd like on one crucial point:

I can't figure out how to navigate in the ring.

Position along the torus can be determined with an accurate clock by checking the time at eclipse, I suppose, but I don't know how to determine radial distance from the center mass (here, the neutron star) or altitude relative to the plane of the ecliptic without a microbarometer on a long rope. Ironically, without a "down", longitude is apparently easier to figure out than either sort of latitude.

[Everyl]

Unfortunately, Niven's stories are less helpful than I'd like on one crucial point:

I can't figure out how to navigate in the ring.

Position along the torus can be determined with an accurate clock by checking the time at eclipse, I suppose, but I don't know how to determine radial distance from the center mass (here, the neutron star) or altitude relative to the plane of the ecliptic without a microbarometer on a long rope. Ironically, without a "down", longitude is apparently easier to figure out than either sort of latitude.

Hmm. Navigating in a gas torus would be pretty difficult. After all, objects with stable orbits at different "altitudes" would probably have slightly different orbital durations, meaning few objects would maintain fixed spacing from any other objects. Maps and charts would be essentially impossible. IIRC, in Integral Trees, the humans didn't have an effective way to navigate the torus, perhaps for that very reason. You'd need a supercomputer tracking thousands (millions? billions?) of objects to keep any sort of reasonable track of where things are and how to get to them from where you are. Or maybe magic, but it sounds like your players may not be the type to accept something like that if you have to use hard sci-fi as a basis for your fantasy setting to satisfy them.

[Trekkin]

Hmm. Navigating in a gas torus would be pretty difficult. After all, objects with stable orbits at different "altitudes" would probably have slightly different orbital durations, meaning few objects would maintain fixed spacing from any other objects. Maps and charts would be essentially impossible. IIRC, in Integral Trees, the humans didn't have an effective way to navigate the torus, perhaps for that very reason. You'd need a supercomputer tracking thousands (millions? billions?) of objects to keep any sort of reasonable track of where things are and how to get to them from where you are. Or maybe magic, but it sounds like your players may not be the type to accept something like that if you have to use hard sci-fi as a basis for your fantasy setting to satisfy them.

There's also the issue of needing really, really precise numbers compared to the range over which they need to be measured. The torus has a habitable volume 1.93 million times that of Earth's (going from the surface to 8,000m); I'm starting to think I ought to focus on a very small section of the torus, although there's certainly room for everything.

EDIT: I'll have to do more math, but maybe using a very wide annular sail would allow the determination of the in-out vector; essentially a mini-integral tree relying on the varying wind speeds at varying radii. That, combined with one heck of a micromanometer, would at least give a radius and vector relative to the plane, although pressure only varies by a few Pa/km so one would need a really long spar and a very long helical Bourdon tube.

DOUBLE EDIT: Or I could remember that anemometers are a thing that exists.

[thorr-kan]

"Feed it to the tree, Clave."

One of my favorite SF oaths anywhere.

If you can get ahold of the old Analogs where IT and TSR were serialized, I seem to remember some diagrams and articles about the physics.

[lunar2]

i remember there was some saying about travelling, where to go one direction, you had to travel a different direction. that's all i remember on the subject.

[Trekkin]

i remember there was some saying about travelling, where to go one direction, you had to travel a different direction. that's all i remember on the subject.

"East takes you out, out takes you west, west takes you in, in takes you east, port and starboard bring you back."

Which is helpful, so long as you know which way east is.

I'm afraid my torus is rather more complex in its orbit than Niven's, though. The general impression I'm getting from people saying Niven's ring doesn't work is that it dissipates too fast, and my own math says it probably gets hotter than a human would like. In consequence, I think I have to roll it once per orbital period.

If the same math still holds, we might as well set the mass of the neutron star to ~2.55124 solar masses, which at our orbital radius gives us a perfectly Earthlike 24 hours; one convenient consequence of the rolling torus is that that period stays constant over the entire cross-sectional area of the Smoke Ring. It also means the torus has seasons, because a given (small) section of the ring will always be on closest to the star at the same position relative to it; again for convenience, putting the Sun-mass star 1.53 AU away for a familiar 365-day year. It's a bit chilly, but somehow I don't think the idealized greenhouse model holds here.

Hugely inconveniently, though, it means now we're dealing with two rotating reference frames at once. We can still determine (relative) longitude by the same method, though; the neutron star is a magnitude -13 object in the sky, and when it and the sun appear to eclipse, the time difference from noon is longitude.

Latitude remains a problem, and one I/we have to solve if we're to have navies and so forth. Niven's Admiralty did it with a network of heliographers at known positions, but that only works within the network.

It's not strictly swords n' sorcery, but the anemometers at least let us establish which way the center is, which when combined with a gyroscopic "up" (since otherwise everything's flippable) and a star-based "in" is at least a direction. Radius can be determined (to within a handful of kilometers) with a helically wound Bourdon tube, assuming no wind.

So it looks like rather than integral trees, we have integral ships -- and anyone with a navy needs to be at least steampunk, or they're going to be lost in the sky in short order, unless there's a simpler way I'm not seeing.

Which, of course, raises the question: how are they getting around?

And what would a flying boat built by, say, elves look like? Dwarves? Drow? Heck, halflings? I'm bad at aesthetics, especially with physics as forgiving as these. Ornithopters work; so do propellers. So do rockets. So, for that matter, do chariots pulled by fleets of birds.

[Grinner]

I don't know much about orbital mechanics, but I do know that this isn't really a plausible setup for extended habitation, barring some serious handwaving.

Human biochemistry relies on gravity. Because of the microgravity environment, the people are likely to be exceedingly anemic, atrophied, and fragile. And this assumes they even survive gestation.

You could say they're adapted for those conditions, but the human form is unsuitable for microgravity environments regardless.

Realism is a fool's errand here.

[Trekkin]

Realism is a fool's errand here.

It is a very good thing I am just such a fool, then, because if bone disease and anemia killed everybody the torus would get very boring.

In all seriousness, though, I think we can add a tiny little handwave here. My players are physicists (sorta), not molecular biologists. If I claim whatever genetic template used by the setting's gods to create humans came with a set of genes that set up a lower limit on tissue density and adjust the pressure of cerebrospinal fluid to avoid intracranial hypertension and so forth, they can accept it rather than insist on dying and it won't look counterintuitive to them.

[Everyl]

If you want to know what flying ships built by various races would look like, try Googling up some Spelljammer art. It's been too long since I've read up on the setting for me to offer any more specific advice, sadly.

[lunar2]

dwarves would favor mechanical propulsion, gnomes chemical, elves magical (if you have magic) or wind (if you don't), halflings animal. humans would use some combination of aesthetics, taking what they think is best for a given area from each of the other races. or, if you do use magic, then humans could be wind powered. orcs would use humanoid propulsion, slaves at bike pedals attached to massive propellers.

as for ship design.

dwarves and halflings have big clan ships, elves use small agile personal flyers, gnomes have ships with scoops to collect samples as they go. humans favor symmetrical appearances wherever possible. probably radial symmetry, since landing isn't an issue.

[Rakaydos]

Re: navigation- I think the best way to deturmine your loction within the ring is with a clock and the positon of the sun.

Inside the ring, you should be able to see a few landmarks: the Arch (A bright track across the sky, that is the rest of the gas torus), the Warp in the Arch (light-altering Neutron Star in the center of the Arch), the Wandering Light, (the orbiting steller component) and the Leaf in the Arch. (the planetary core)

Measuring the angle between the Warp and the Light will give an absolute position at any given point, based on trigonometry. Measuring how close the Warp is to the edge of the Arch will tell how far "orbital north" or "orbital south" you are, (if the warp appears low in the arch, you are VERY low in the gas torus) though that isnt exacty useful information. But tracking the location of the Leaf, relative to the Arch, the Warp, and the Light, should give you an approximate location in the ring. And as they change over time, you can tell if the Leaf is Rising in the arch or Falling.

[lenlenlen1]

Is there a cone shaped area behind the gas giant in a gas torus that is relatively windless and potentially habitable?