50 ms·

No. In even a modest(hah!)structure like Larry Niven's Ringworld the tensile strength required to hold it together exceeds that of any known material. Sorry I'

by russell 12y ago

No. In even a modest(hah!)structure like Larry Niven's Ringworld the tensile strength required to hold it together exceeds that of any known material. Sorry I'm too lazy to dig up the specific reference, but I'll give you a pretty picture instead. http://www.dennisantinori.com/Resources/Ringworld/ http://www.dennisantinori.com/Resources/Ringworld/ Edit: a reference >>> Peter Weston passed the word from a British college professor: the tensile strength of the Ringworld floor needs to be on the order of the force that holds an atomic nucleus together. From such stuff you could make a garbage bag that would hold a thermonuclear explosion. http://www.larryniven.net/stories/macrostructures.shtml http://www.larryniven.net/stories/macrostructures.shtml

gliese1337 12y ago
The Ringworld only requires such enormous tensile strength because it's spun to produce gravity on the interior surface. If you don't plan to inhabit the interior surface, there's no need to spin it, and the problem goes away. A sufficiently thin continuous sphere can be held up entirely by radiation pressure, but still presents engineering challenges with damping oscillations; a continuous structure is likely to tear itself apart just because it's practically impossible to keep everything absolutely perfectly balanced on such a large scale. Which is why, per the article, the Dyson Swarm, a sphere made of lots of independently flying satellites, is much more plausible. Incidentally, there are ways to eliminate the tensile load on a ringworld; you "just" have to stack enough suborbital mass outside of it (coupled by maglev rails or some such set up) so that the compression balances it out.
- electromagnetic 12y ago
  I wonder how feasible it would be to rotate a ringworld at a speed not to replicate gravity, but to negate the sun's gravity. So at 1AU it would orbit in roughly the same length of time as Earth itself.
  - TheLoneWolfling 12y ago
    You'd actually want to rotate it at slightly faster than orbital velocity, I think. Tension is much stronger than compression, especially at larger scales. But then you don't have the "nice" way of keeping the atmosphere in.
    - electromagnetic 12y ago
      My thought was something like a Stanford Torus, because then you could simply add additional rings on different orbital inclinations to build an almost sphere out of rings (reminiscent of M.C. Eschers drawing) and given good design you could create rings with day night cycles.

by russell 12y ago

gliese1337 12y ago

The Ringworld only requires such enormous tensile strength because it's spun to produce gravity on the interior surface. If you don't plan to inhabit the interior surface, there's no need to spin it, and the problem goes away. A sufficiently thin continuous sphere can be held up entirely by radiation pressure, but still presents engineering challenges with damping oscillations; a continuous structure is likely to tear itself apart just because it's practically impossible to keep everything absolutely perfectly balanced on such a large scale. Which is why, per the article, the Dyson Swarm, a sphere made of lots of independently flying satellites, is much more plausible. Incidentally, there are ways to eliminate the tensile load on a ringworld; you "just" have to stack enough suborbital mass outside of it (coupled by maglev rails or some such set up) so that the compression balances it out.

electromagnetic 12y ago
I wonder how feasible it would be to rotate a ringworld at a speed not to replicate gravity, but to negate the sun's gravity. So at 1AU it would orbit in roughly the same length of time as Earth itself.
- TheLoneWolfling 12y ago
  You'd actually want to rotate it at slightly faster than orbital velocity, I think. Tension is much stronger than compression, especially at larger scales. But then you don't have the "nice" way of keeping the atmosphere in.
  - electromagnetic 12y ago
    My thought was something like a Stanford Torus, because then you could simply add additional rings on different orbital inclinations to build an almost sphere out of rings (reminiscent of M.C. Eschers drawing) and given good design you could create rings with day night cycles.