Ringworld vs OTU a comparison

[Tom Kalbfus]

OK, interesting ideas, but I still don't think the outer stabilizing ring is going to work.

Just because contact is frictionless doesn't mean no forces can be applied from one surface to the other, it only means forces perfectly parallel to the plane of contact will result in no transfer of force.

If either ring isn't perfectly homogenous and perfectly rigid, it's never going to be perfectly circular. This means the direction of motion of the inner ring at any point will never be perfectly parallel to the plane of contact with the outer ring at that point. This irregularity in the shape of the rings is going to result in net forces between the rings out of their plane of contact, which will cause a braking effect on the inner ring.

The only way out is to make the rings both perfectly circular and perfectly rigid, which means we're back to super-science materials and the inner ring wouldn't need the outer ring to stabilize it anyway.

Simon Hibbs

You have no way of knowing if the resultant forces will exceed the tensile strength of the material. The most significant force would be the outward centrifugal force, and that's counterbalanced by the weight of the outer ring under the star's gravity. Besides, what are your worried about, its only fiction? The only important thing is to make people like you try hard to find a way for it not to work, most casual readers don't care, all they need is to be convinced enough that they don't get a feeling that its rubber science. For instance, you don't have to try very hard to figure out how a light saber or an x-wing fighter is not going to work. Maybe you think a ringworld is too good to be true and it must be impossible, then you go look for a way for it to be. Lets me just say that residual forces of friction between the two rings would be a lot less than the outward centrifugal force against the inner ring along if not compensated for by the weight of the outer ring. The only resultant force we have to worry about is an outward force, a sideways force would slow down the ringworld or speed up the outer ring.

I don't think the ringworld needs to be perfectly rigid, it doesn't need to be a perfect circle either, what it needs to be able to do is stretch without breaking, the weight of the outer ring takes care of most of the outward forces, planets orbit in ellipses after all, and in every position in its orbital ellipse, the planet is in a position of equilibrium. When a planet is in orbit, the planet's weight under the gravity of the star equals the centrifugal force of its orbit. With a ringworld its much the same, only your transferring the weight of the outer ring to the ringworld through the interactions of a magnetic field. The ringworld can stretch and it can contract to some degree so as to maintain equilibrium between total weight and centrifugal force, the thing to remember is the centrifugal force is that of the ringworld only, while the inward weight is that of the ringworld plus the outer ring combined total inward weight plus total tensile strength of both rings equals outward centrifugal force of the ringworld alone, as the outer ring does not rotate. Everything else is just a technical detail, simply building a structure that large is a huge undertaking, we can only talk about ringworlds in terms of fiction at this point, no one is seriously considering building one at this moment.

 

[simonh]

I'd just like to say I'm really enjoying this thread and think the campaign concept is lots of fun. I'd jump at the chance to play a game in this setting.

Maybe you think a ringworld is too good to be true and it must be impossible, then you go look for a way for it to be.

Oh, not at all. I'm a big fan of Ringworlds and have run several games using the old Chaosium roleplaying game. It's a fantastic idea and I have no problem with imagining up supermaterials like Scrith, if that's what it takes to have a ringworld in my fiction.

I think about this in a similar way to my point about jump drive violating relativity in another thread. I wan't saying that we shouldn't use Jump Drive in our SF games, but that we shouldn't pretend that we can wish the problem of relativity away. An SF setting that posits a brazenly SF stardrive get's my respect for being honest about what rules it's breaking. One which says that it gets round relativity by using warp-drive-this and wormhole-that 'without violating relativity' is just picking a physics fight. Why can't we just be honest about the rules we're choosing to break? Similarly pretending the ring can be made out of ordinary materials somehow is just asking for people to question and investigate your explanation as to how that could be done and what the other consequences of that solution would be.

My point is that the outer supermassive stabilization ring wouldn't work without all kinds of additional fixes and super-science tweaks. I don't think it's possible to eliminate the need for super-materials. I'd rather bite the bullet and use scrith rather than pretend that it's really possible to build the ring out of conventional materials. Throwing hundreds of times the ring's own mass and an enormous frictionless superconducting mega-rail at the problem, and then congratulating ourselves on how realistic that is, just isn't very convincing.

To me, using scrith (or something like it) is acknowledging the fact that in reality what we're doing here is impossible, and this acknowledgement is being more honest and respectful to the reader.

Simon Hibbs

 

[Tom Kalbfus]

I'd just like to say I'm really enjoying this thread and think the campaign concept is lots of fun. I'd jump at the chance to play a game in this setting.

Maybe you think a ringworld is too good to be true and it must be impossible, then you go look for a way for it to be.

Oh, not at all. I'm a big fan of Ringworlds and have run several games using the old Chaosium roleplaying game. It's a fantastic idea and I have no problem with imagining up supermaterials like Scrith, if that's what it takes to have a ringworld in my fiction.

I think about this in a similar way to my point about jump drive violating relativity in another thread. I wan't saying that we shouldn't use Jump Drive in our SF games, but that we shouldn't pretend that we can wish the problem of relativity away. An SF setting that posits a brazenly SF stardrive get's my respect for being honest about what rules it's breaking. One which says that it gets round relativity by using warp-drive-this and wormhole-that 'without violating relativity' is just picking a physics fight. Why can't we just be honest about the rules we're choosing to break? Similarly pretending the ring can be made out of ordinary materials somehow is just asking for people to question and investigate your explanation as to how that could be done and what the other consequences of that solution would be.

My point is that the outer supermassive stabilization ring wouldn't work without all kinds of additional fixes and super-science tweaks. I don't think it's possible to eliminate the need for super-materials. I'd rather bite the bullet and use scrith rather than pretend that it's really possible to build the ring out of conventional materials. Throwing hundreds of times the ring's own mass and an enormous frictionless superconducting mega-rail at the problem, and then congratulating ourselves on how realistic that is, just isn't very convincing.

To me, using scrith (or something like it) is acknowledging the fact that in reality what we're doing here is impossible, and this acknowledgement is being more honest and respectful to the reader.

Simon Hibbs

The problem is we're living in the early 21st century, we don't know what solutions would be arrived at to hold the ringworld together, remember the thread on the "Impossible Drive" NASA recently had a test of a supposedly reactionless drive and it worked, it provided a tiny bit of thrust without expending any propellent. The people on the floor of the ringworld, don't know the details of how its held together, if they did some digging, they would find they could dig down about 40 meters through dirt and bedrock, and then they find they hit something extremely hard which they can't penetrate, they don't know precisely how hard it is, except that nothing they've got can put a dent in it. Perhaps not make it so obvious, an intermediate layer of some rubbery material separates the ringworld's structural material from the bedrock, the rubbery material is a nanotech material which regenerates as penetration is attempted, it gets harder and more rigid the further one attempts to penetrate, and holes produced quickly close up and can destroy the drill bit in the process. Explosions just get deflected upward from the surface, a few centimeters of the rubbery material gets vaporized, but them quickly heals. That way I choose not to reveal the structural support material, which can be a number of things. I'm just throwing out some possibilities here.

1) It could be something like Scrith, which can be touched, but is a frictionless material.

2) It could be magmatter.
Magmatter is composed of atoms made of elementary particles called magnetic monopoles. A monopole is much like a proton or an electron, except instead of having an electrical charge of + or - it has a magnetic charge of North or South. Basically all particals we know about are diamagnetic, that is they have both a North and a South magnetic polarity, Monopoles are the exception, they can have a magnetic North without a magnetic South, so far no magnetic monopoles have been found. If they exist, they would require a lot more energy to make and are also much more massive than their electric counter parts the proton and the electron A magmatter atom equivalent to say hydrogen, would have a massive monopole with a magnetic North charge at the center, with a less massive monopole orbiting it with an equal but opposite magnetic charge of South, since these particles are more massive than protons and electrons, the atoms they form are much smaller. A magatom itself, with north and south monopoles, is about the size of a proton within the nucleous of a normal atom. To make heavier elements than maghydrogen, we have magneutrons which have no net magnetic charge.

The tricky thing about magmatter is if I comes in contact with ordinary matter, such as protons and neutrons, in converts those to energy as if they came in contact with antimatter, without the magatoms being destroyed themselves! So if the ringworld is held together by magmatter it needs to be kept separate from ordinary matter otherwise we have big explosion. Some kind of superconducting material is required to repel of the magmatter layer without coming in contact with it.

3) the third idea is we just have massive quantities of ordinary nonrotating matter, maybe requiring super science material or technology, but less than the first two I think.

4) Possibly the ringworld itself is a simulation, and programming force fields within the simulation holds the ringworld together which otherwise faithfully simulates real world physics. the computer simulating it is simply a orbital ring of solar collecting computer material, this would be the easiest to build as its only a supermassive computer that does a lot of number crunching.

So I would leave 1, 2, 3, and 4 as all possibilities, neither confirming or denying which for as long as possible and keep the players guessing which one it is.

Oh by the way, I left some parameters on my ringworld in the last post of my ringworld timeline thread. Basically we have 11 characters in a boat, 1 captain, 2 crewmembers and 8 passengers (if you like you can roll some up, basically they are early tech level 8, from our time or seemingly so)that get caught up in the Bermuda triangle and end up on a ringworld ocean near an island in he shape of Bermuda, but seemingly uninhabited. The parameters assume real world physics as far as they go whether it is the "real world" or a simulated "real world" by a computer, it attempts to appear as relatively hard science while keeping the rubber science to a minimum.
All the careers are available so long as they are consistent with the modern world.