This reminds me not only of Ringworld, but also the Cageworld series by Colin Kapp (https://en.wikipedia.org/wiki/Cageworld_series)

Quote from: GeekyBugle on May 24, 2022, 01:51:02 AM

Quote from: Pat on May 23, 2022, 10:38:59 PM

Quote from: GeekyBugle on May 23, 2022, 10:30:49 PM

Quote from: Pat on May 23, 2022, 06:55:26 PM
Here's an interesting twist that's possible with a torus, but not a band.

Ringworld has gravity because it's in orbit around the Sun. That means you can only use one side of the band, and need to match velocities to visit the Ringworld.

But with a torus, you don't need to spin the big hoop for gravity. Instead, you could twist it. This works best if it's designed in a modular form, with different roughly cylindrical modules connected end to end in a long Sun-circling chain. That way, you can spin each of the modules independently, giving them each a different gravity. Since you're spinning cylinders around their axis, the axis would a zero-G or microgravity zone, and it would be the natural transition point where you can pass from one module to the next. Visiting the torus would be much easier, since the orbital velocity can be lower (you'd still need some spin).

I like it but it has a fatal flaw: It can't work mechanically, you can't have the modules interconected and spining on their axis. You would need a space between cylinders and maybe conect them by a relatively thin point in their axis.

But it would also create a day/night cycle.

You're talking about unobtainum materials and gravity control anyway, so creating the equivalent of frictionless bearings/locks in zero-G isn't much of a stretch.

Oh, it's not the friction I'm "objecting" to, it's just that it wouldn't look as a continual tube from "close" distance.

Each section would need to be a perfect cylinder, which means you'd need a space between each, bigger on the side of the torus fartest from the star.

In exchange it solves the night and day cycle in a perfect fashion.

It also means no inner hyperloop connecting different modules.

Gotcha, but assuming my math is correct, the difference is trivial. The Ringworld has a circumference of 970,000,000 km. If we use that as the inner circumference of the torus and assume each module is 1 km wide, then the outer circumference becomes 970,000,006.283 km. If each cylinder is 10 km long, that means the gap between the side of the cylinder away from the Sun would be 1/15th of a mm (millimeter) longer than the gap on the side closest to the Sun. Even if we scaled the cylinders up to a 1,000 km across and 10,000 km long, it's only 65 m.

Just to give some idea of the immensity the ring, it would take 97 million of the smaller 10 km long cylinders to circle the Sun. Even with the bigger 10,000 km long cylinders, there will still be 97,000 of them.

And a hyperloop would make sense running through the center of all the cylinders. In fact, that could be the unobtanium -- instead of a scrith ribbon, have a giant string of some wondrous material, similar to proposed orbital beanstalks, but much larger in scale, which forms a continuous loop around the sun. I'm not sure how thick the string would be, but it would be substantial in size yet much smaller than each cylinder. Give it magnetic or gravitic or quantum properties, which the modules use to "attach" (without contact) to the string. This would be done by rings, at least one at each end of a cylindrical module, perhaps many running along the inner axis. The rings would encircle the string, maintaining a constant distance, thanks to the magnetic/gravitic/quantum properties. Monorails or the equivalent could run down the string, though that might make the most sense if we make the string hollow -- need to think about it a bit more.

Quote from: GeekyBugle on May 23, 2022, 03:23:09 PM
Yes, why did they choose a torus and not a ring, that's a kind of important question I hadn't thought about.

Some civilization has an active patent on the ring design.  You don't want the galactic patent office after you.

Why not an artificial star?  Surely if they can build this huge torus they can create  an artificial star just the right size.

Better yet a hollow sphere with a star in the center.

Quote from: GeekyBugle on May 24, 2022, 01:59:18 AM

Quote from: HappyDaze on May 23, 2022, 04:08:33 PM

Quote from: GeekyBugle on May 23, 2022, 03:56:31 PM

Quote from: Pat on May 23, 2022, 03:29:18 PM

Quote from: GeekyBugle on May 23, 2022, 03:23:09 PM
In the orbit of mercury and then you have no photosyntesis because you lack enough light.

Are you confusing Mercury with one of the outer planets?

No, you need to block it to not get cooked/blinded. Light carries heat too.

Isn't that (radiant heat) pretty much the only way a star gives off heat? I suppose mass elections can give off heat too, but I'd imagine it's tiny in comparison (unless you're unfortunate enough to get hit by one).

I'm going to assume you're not talking about elections nor erections, so it leaves what? ejections? As in solar flares? yeah that's the other way a star gives off heat. I mean if it hits you you get engulfed by a flame at 10's of millions of kelvins.

Yeah, should have been "ejections" up there. Damn autocorrect.

Quote from: VisionStorm on May 23, 2022, 04:40:03 PMEven if it were to still circle a star, this thing would need to be so huge as to beg credulity.

The smallest star we have ever found is EBLM J0555-57 which is about the size of Saturn with a mass 85 times that of Jupiter. Any civilization setting out to build such a structure could pick and choose what size star they want so the size of the ringworld is flexible (but still huge). That fact that people in this thread are using our Sun as a basis is just an example of Earthling bias.

I also agree that having it orbit around a star is a unnecessary. If you are making it a tube, then there isn't any reason for one of the sides of the tube to be transparent to let in light as it would be easier to just use a massive heat lamp moving across the inner surface of the tube to provide the necessary light and heat. At that point all you need is a sufficient power source.

But ultimately, a dyson sphere or ringworld is utterly pointless. Any civilization sufficiently advanced to build such a thing wouldn't have a need for such a unstable design. If they need living space, it would be much easier to build a few artificial planets. These would be self contained and not rely on a magical substance to keep the entire thing from tearing itself apart. I think that a massive ring of hundreds of artificial planets orbiting the same star would be a more original and more useful RPG campaign design as each planet could have it's own unique atmosphere, gravity, and climate. At that point all you would need to do is decide how to move from one to another, such as a portal, a regular space taxi system, or even a giant canon that shoots you from one planet to the next. 

Again, I've asked twice but I still don't know the OP's point in making such a thing. Is this for a fantasy RPG campaign? Sci-fi? Do the people living there know what they live upon? Do they have technology to understand it? Can they fix it or control it in any way? Unless these questions are answered, there isn't much point in discussing potential designs.

Quote from: hedgehobbit on May 24, 2022, 08:52:36 AM
But ultimately, a dyson sphere or ringworld is utterly pointless. Any civilization sufficiently advanced to build such a thing wouldn't have a need for such a unstable design. If they need living space, it would be much easier to build a few artificial planets. These would be self contained and not rely on a magical substance to keep the entire thing from tearing itself apart. I think that a massive ring of hundreds of artificial planets orbiting the same star would be a more original and more useful RPG campaign design as each planet could have it's own unique atmosphere, gravity, and climate. At that point all you would need to do is decide how to move from one to another, such as a portal, a regular space taxi system, or even a giant canon that shoots you from one planet to the next. 

That's not that far from better conceptions of a Dyson sphere. A lot of not very good sf (Star Trek comes to mind) default to a Dyson sphere as a literal shell, but that makes little sense. The point of a Dyson sphere isn't about enclosing a star in something solid, rather it's about capturing the entire energy output of a Sun. The "shell" could be a swarm of objects that together occlude all the electromagnetic emissions. These could could be many giant reflective mirrors just a few atoms thin, mixed in with a wild array of habitats in concentric but offset orbits. This allows a Dyson sphere to develop gradually, instead of requiring a single massive engineering project, and doesn't have the same issues with gravity, tensile strength, and all the other problems. I suggested a similar partial Dyson sphere earlier in the thread, with multiple toruses in different orbits.

Quote from: DocJones on May 24, 2022, 08:22:32 AM

Quote from: GeekyBugle on May 23, 2022, 03:23:09 PM
Yes, why did they choose a torus and not a ring, that's a kind of important question I hadn't thought about.

Some civilization has an active patent on the ring design.  You don't want the galactic patent office after you.

Why not an artificial star?  Surely if they can build this huge torus they can create  an artificial star just the right size.

Better yet a hollow sphere with a star in the center.

Yes, exactly, The Niveans are known to enforce their patents very harshly. 

Quote from: HappyDaze on May 24, 2022, 08:38:21 AM

Quote from: GeekyBugle on May 24, 2022, 01:59:18 AM

Quote from: HappyDaze on May 23, 2022, 04:08:33 PM

Quote from: GeekyBugle on May 23, 2022, 03:56:31 PM

Quote from: Pat on May 23, 2022, 03:29:18 PM

Quote from: GeekyBugle on May 23, 2022, 03:23:09 PM
In the orbit of mercury and then you have no photosyntesis because you lack enough light.

Are you confusing Mercury with one of the outer planets?

No, you need to block it to not get cooked/blinded. Light carries heat too.

Isn't that (radiant heat) pretty much the only way a star gives off heat? I suppose mass elections can give off heat too, but I'd imagine it's tiny in comparison (unless you're unfortunate enough to get hit by one).

I'm going to assume you're not talking about elections nor erections, so it leaves what? ejections? As in solar flares? yeah that's the other way a star gives off heat. I mean if it hits you you get engulfed by a flame at 10's of millions of kelvins.

Yeah, should have been "ejections" up there. Damn autocorrect.

The only reason I miss it here it's because I can make a spelling error and don't notice. But I only used the forum's correction system, not an automatic one.

Quote from: hedgehobbit on May 24, 2022, 08:52:36 AM

Quote from: VisionStorm on May 23, 2022, 04:40:03 PMEven if it were to still circle a star, this thing would need to be so huge as to beg credulity.

The smallest star we have ever found is EBLM J0555-57 which is about the size of Saturn with a mass 85 times that of Jupiter. Any civilization setting out to build such a structure could pick and choose what size star they want so the size of the ringworld is flexible (but still huge). That fact that people in this thread are using our Sun as a basis is just an example of Earthling bias.

I also agree that having it orbit around a star is a unnecessary. If you are making it a tube, then there isn't any reason for one of the sides of the tube to be transparent to let in light as it would be easier to just use a massive heat lamp moving across the inner surface of the tube to provide the necessary light and heat. At that point all you need is a sufficient power source.

But ultimately, a dyson sphere or ringworld is utterly pointless. Any civilization sufficiently advanced to build such a thing wouldn't have a need for such a unstable design. If they need living space, it would be much easier to build a few artificial planets. These would be self contained and not rely on a magical substance to keep the entire thing from tearing itself apart. I think that a massive ring of hundreds of artificial planets orbiting the same star would be a more original and more useful RPG campaign design as each planet could have it's own unique atmosphere, gravity, and climate. At that point all you would need to do is decide how to move from one to another, such as a portal, a regular space taxi system, or even a giant canon that shoots you from one planet to the next. 

First off I LOVE your idea of a ring of worlds, it's the fleet of the worlds. How many AU would each planet need to be from each other not to tear each other appart?

Quote from: hedgehobbit on May 24, 2022, 08:52:36 AM

Again, I've asked twice but I still don't know the OP's point in making such a thing. Is this for a fantasy RPG campaign? Sci-fi?

Second, I thought the title of the thread answered that? It's Sci-Fi of a high handwavium and unobtanium sort.

Quote from: hedgehobbit on May 24, 2022, 08:52:36 AM

Do the people living there know what they live upon? Do they have technology to understand it? Can they fix it or control it in any way? Unless these questions are answered, there isn't much point in discussing potential designs.

That's part of the reason for the thread, my idea was to collectivelly create an OGC setting, free for anyone to use, in The Ringworld the "natives" don't know they live in an artificial structure and though there's technology to fix it they don't know where or how to use it.

Of course that doesn't have to be that way, and in the novels this is true only of the small fraction that's explored.

Welp, while the Klemperer Rosette seems like a solution that needs no "magic" to remain stable turns out that's not true. Each body in the Rosette needs engines to keep it always in place counteracting any force that might push/pull it out of it's perfect placement in the construct.  So engines attached to a planet, powerful enough to move it (yes it needs more than the one engine) that somehow don't tear the thing appart nor destroy the ecosystem when fired.

Source: https://en.wikipedia.org/wiki/Klemperer_rosette

One partial solution is to use a hexagonal rosette, and then orbit them around a white dwarf. That's a more stable configuration because the planets will all sit in each other's Lagrange points. And you can keep the planets closer together, because with a smaller sun the goldilocks zone should be closer (maybe 0.01 AU, per this). The problem is there is some debate about the suitability of white dwarfs, but in fiction when the answers is unsure you can just pick the one you prefer.

The basic issue with lots of planets is the three-body problem: Any system with more than 2 objects in orbit is inherently unstable, over long periods of time. You'd need a lot of planetary engines. The Solar System is fairly stable right now because the major planets have all cleared their orbits of most of the detritus, but even so the motions of NEOs and so on are inherently unpredictable over time.

Quote from: Pat on May 24, 2022, 08:26:10 PMThe basic issue with lots of planets is the three-body problem: Any system with more than 2 objects in orbit is inherently unstable, over long periods of time.

If this is true, how do the rings around Saturn and Jupiter remain stable?

Quote from: hedgehobbit on June 04, 2022, 10:53:37 AM

Quote from: Pat on May 24, 2022, 08:26:10 PMThe basic issue with lots of planets is the three-body problem: Any system with more than 2 objects in orbit is inherently unstable, over long periods of time.

If this is true, how do the rings around Saturn and Jupiter remain stable?

They're not. The masses of the individual objects in the rings are so small, that we can approximate the results by ignoring their effect and treating the Sun and Saturn (or Jupiter) as a two-body system, which is a reduced form of three body problem. But even that degenerate case, the system will become unstable, over a sufficiently long period of time, which may be hundreds of millions or even billions of years. But objects of more comparable masses, like a string of many Earth-sized planets will become unstable much faster.

Decent summary of the three-body problem: https://www.youtube.com/watch?v=et7XvBenEo8

Quote from: Pat on June 04, 2022, 12:32:38 PM

Quote from: hedgehobbit on June 04, 2022, 10:53:37 AM

Quote from: Pat on May 24, 2022, 08:26:10 PMThe basic issue with lots of planets is the three-body problem: Any system with more than 2 objects in orbit is inherently unstable, over long periods of time.

If this is true, how do the rings around Saturn and Jupiter remain stable?

They're not. The masses of the individual objects in the rings are so small, that we can approximate the results by ignoring their effect and treating the Sun and Saturn (or Jupiter) as a two-body system, which is a reduced form of three body problem. But even that degenerate case, the system will become unstable, over a sufficiently long period of time, which may be hundreds of millions or even billions of years. But objects of more comparable masses, like a string of many Earth-sized planets will become unstable much faster.

Decent summary of the three-body problem: https://www.youtube.com/watch?v=et7XvBenEo8

Furthermore, Saturn's rings are made of mostly dust, the next big mass isn't near enough to have an effect we can see. And the Sun is too far away to break Saturn's pull.

But, posit a big enough comet passing near enough and you quickly see the problem.

Now, in a ring of same mass bodies ANY disrupting influence will rapidly destroy the balance since the ring's bodies are close enough to affect each other even if you place them in their mutual lagrange points. Even with their star's pull.

What we see as a stable orbit really isn't, but it's decay is so slow as to be something that needs billions of years.

Our moon is escaping earth, slowly but surelly moving away from earth's pull.

Just googling around and found this article based on some research done on ring system in 2010.

https://planetplanet.net/2017/05/03/the-ultimate-engineered-solar-system/

The basic gist is that large numbers of planets co-orbiting is actually more stable than a smaller number (and anything less then 7 is unstable). So a ring of 42 earth sized planets could orbit the sun in the same orbit. Plus you could also put multiple rings of planets in slightly different obits (all in the habitable zone) meaning our sun could possibly have 252 total Earths orbiting it. The actual number is based on the ratio of the bigger body to the lesser body. The higher the ratio, the more objects can remain in orbit because they can be closer to one another.

In this arrangement, each planet would be 100 times further away than our moon. By my calculations, this would make the nearby Earths appear to be about 4% of the size of our moon.


Anyway, that's enough for my off topic idea.