Monday, November 6, 2017

Dianne Harris asks: Why are Culture Orbital's circles and not mobius strips?

Dianne Harris asks: Why are Culture Orbital's circles and not mobius strips?

I have no idea! Would this be awesome?

Alternatively, would everyone die?

17 comments:

  1. Mobius strips are just cute tricks. If you can build a ringworld that people can live on the outside of, you can build one.

    However, if you can build a ringworld people can live on the outside of, there's no point in a ringworld.

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  2. Orbitals are a bit smaller than ringworlds qua Niven's Ringworld -- several orders of magnitude -- and the point is to house people, isn't it?

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  3. Oh, I always thought those were discs, not rings.

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  4. Ok, done the research now. That's weird. Why make a ring-world style habitat, but only 1% the diameter?

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  5. Who says they aren't? There are what, a dozen? Less? orbitals described in the culture books, that's hardly a representative sample.

    At culture level technologies, everything is magic. They can make ring worlds, worlds that are just flat slabs, whatever they want and keep gravity and atmosphere working on them so there's no reason they couldn't make a mobius strip habitat if some group wanted one. And just like the others if they lost power it would catastrophic.

    Also, probably because the author didn't think of it at the time.

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  6. Maybe because after Banks spent all that time in Matter describing a new application of artificial stars ("roll-stars"), he didn't really want to spend more time explaining how the folks on the outer sides of a mobius strip ever get sun-shine?

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  7. I don't remember there being artificial gravity? I thought they were rings because they spun.

    If not, maybe they are setup that way incase artificial gravity fails or needs to be disabled for maintenance.

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  8. Yep, is described when they arrive on Vavacth in Consider Phlebas. The orbitals are spun up to provide artificial gravity, they have huge walls along the inside edges to keep the atmosphere in.

    They are the diameter they are because at 1g of spin they rotate once a day.

    I don't remember if there is any reasoning behind the width of the orbital.

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  9. Am I remembering a different series where they talk about having habitats that were effectively just rectangular slabs? That could be...

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  10. Matt Johnson The orbitals could have been built with a ring of inward facing rectangular slabs. I don't remember all the details.

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  11. Huh. apparently I /am/ conflating the Culture with some other series, because I have very distinct memories of having something like the individual "plates" be the whole of the habitat. So my earlier post is invalid in this context.

    Though their technology is still kinda magic...

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  12. The Culture absolutely has artificial gravity. They have whimsical gravity.

    Most of "why do they do it in way X rather than way Y?" is going to be stylistic, rather than engineering based.

    I love the determined engineering mindset of all the folks who are asking "What happens if the power fails?" but the answer is "Well ... first, that won't happen, but if it does I suppose they'll just draw on people's personal anti-matter reactors, or a few of the trillions of sentient drones will alter their five-space field harmonics to funnel energy from the zero-point grid underlying the multiverse, and power the entire habitat. But that would be a chore, so you'd definitely want to figure out how the laws of physics changed such that the dedicated power systems stopped working."

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  13. Matt Johnson: No, you've got it right. That's the description of a habitat-in-assembly in Player of Games. Other books discuss habitats already completed (or nearly so).

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  14. Well, while the technology level of the culture does imply a certain level of improbability in accidental failure, I don't think you could rule out deliberate sabotage, so a "What happens in a power outage" isn't a totally besides the point question. It's basically magic power systems vs. magic power disruption weapons....

    Oh... thank you Tony! I was looking around and couldn't find a match...

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  15. In at least one book I've read, onboard the Orbitals, they have these distributed cities. The cities have skyscrapers, right?

    Enough skyscrapers for the population, turns out, though it'll be cozy.

    And those skyscrapers are also spaceships. So, another layer of defense built right in. If the Hub fails and suddenly you don't have any sort of coordinated energy infrastructure, then cram into spaceships the size of skyscrapers.

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  16. I was also thinking that it would be made of 360 or so links/time zones and be flexible and in motion, kinda like a old metal stretchy wrist watch, so that people get day night and something like 4 or 8 seasons. Maybe every section celebrates twist day when they go from outside to in. Maybe instead of saying it is 5 o clock somewhere, they say it is twist day somewhere, and it is like a new years style event, for each section.

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  17. The Culture considered 4 sextillion kilograms sufficient to construct an Orbital with a surface area of 10 billion square kilometres; the Orbital would have a maximum population of 50 billion.

    On Mass:
    sextillion = 10^21, so 4 * 10 ^ 21 kg
    Mass of earth: 5.972 × 10^24 kg, so 6 * 10 ^ 24 kg

    So, that's under one part in a thousand of the mass of earth.

    On Surface Area:
    Surface area of the earth is 510.1 million km², so call it 5 * 10 ^ 8 km^2.
    Surface area is the hab is 10 billion km^2, so call it 1 * 10 ^ 10.

    So, that's 20 times the surface area.

    By that metric, earth should have a population of only some 2.5 billion.

    That's why you use an Orbital; they don't take a ridiculous amount of matter like a ringworld or a dyson sphere. on the scale of mega-scale space habitats, they are relatively low key.

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