Unifying Contradiction (swestrup) wrote in scientistgamers,
Unifying Contradiction

Dyson Sphere Revisited.

Many years ago, I came up with an idea for a variation on a Dyson Sphere which would have the advantage of

a) Internal gravity without gravitic generators
b) Instability on only 1 axis rather than 3 (and possibly correctable to passive stability)

I've always wanted to use this in a Role-playing game, but I've never been able to do the math to solve for the outer shape of the thing (which isn't spherical).

Now that I have mathematica, I may one day take another shot at it (but I'll have to go and restudy my vector calculus, as I haven't needed it in the 20 years since I left College).

In the meantime, if anyone else want to try and do the math, there is a write-up here in my journal.
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My understanding of this was that (books and games notwithstanding), gravitational and stress forces would likely rip such a structure apart.

If I recall correctly, based on calculations of mass and volume, Niven's RingWorld included a structural material with a density equivalent to that of water, yet it was supposed to have obscenely good strength.

If in doubt, I'd go for a highly fractal shape with minimal mass (think like a net, only layered and interconnected). Ideally, you could do a series of independent habitation areas orbiting the sun, with each rotating to induce fake gravity. Then, string together some nanostructured carbon cables between habitats to allow easy transportation, and you've got a sort of ring world.

As I say somewhere in the linked conversations, its hard to do a stress analysis of something with an unknown shape. Even then, with carbon nanotubes having theoretical tensile strengths in the region of 200 Gigapascals, we're a lot closer to having working materials than we used to be.

In the 15 years since I came up with this idea, I've tried to find any reference whatsoever to any tensile strength calculations that anyone has ever done on any sort of similar megastructure, or any work on the theoretical ultimate strengths of materials and so far I haven't found anything. If you know of any references to information that would make the calculations more tractable, I'd love to hear it. Niven says in one of his books that he's been shown calculations on the required properties of scrith, but he's never said any more than that, so far as I've been able to find.