I've read that the ringworld's design is actually unstable, and that it would drift and eventually collide with the star it was supposed to orbit. How is this flaw corrected in the subsequent stories?

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    @neilfein It's fixed now, thanks for bringing it up.
    – liewl
    Jan 20, 2011 at 17:28
  • Note: the Ringworld is not in orbit. Or, if you prefer each bit is in an independent, highly hyperbolic orbit; but the problem arises because of the rigid body dynamics of the thing and would still occur if you slowed it down to orbital speed (and you'd lose the air). Apr 13, 2014 at 17:43

2 Answers 2


Niven didn't have any intention of writing a sequel, but this big flaw in the Ringworld led him to write The Ringworld Engineers. In that novel, the ring has several attitude jets that are powered by the solar wind.

The plot revolves around the characters attempting to locate the control and repair center of the Ringworld in order to replace some of the broken and stolen attitude jets.

Teela Brown, now a protector stage human, realizes that it is too late to stop the drift by simply fixing the attitude jets. The only solution she envisions requires using the Meteor Defense System, a supercondutor grid that lies below the Ringworld's surface and can generate powerful magnetic fields, to induce an enormous solar flare. Such a flare would provide enough power to rectify the Ringworld's orbit, but would kill trillions of Ringworld inhabitants. Unable to live with that choice because of her protector instincts, she engenders a plan for Louis Wu and his crew to kill her and then put the plan into motion.


The Ringworld is outfitted with engines that stabilize the ring against wobble and from falling into the sun, they harvest solar wind for power.

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    And some of the residents took some of the engines to make ships to escape from the ringworld.
    – Tangurena
    Jan 19, 2011 at 1:29
  • you would think that by messing about with the shadow squares, the light pressure on the ring could be used to some effect.
    – JustJeff
    Jan 19, 2011 at 1:36
  • @JustJeff certainly negligible against something as massive and not highly reflective as the Ringworld. Jan 19, 2011 at 1:37
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    @JustJeff If you mess with the shadow squares to balance out instability in the Ringworld, then you'll introduce instability into the shadow squares instead -- you'll have to arrange them so that some arcs experience more light pressure than others.
    – Mike Scott
    Jan 20, 2011 at 20:19
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    Interesting how Niven came to know that, as he writes in the preface of "Ringworlds's Children": At the 1970 World Science Fiction Convention there were MIT students in the halls chanting, "The Ringworld is unstable! The Ringworld is unstable!" (Did the best that I was able...hence, attitude jets.)
    – Bobby
    Dec 15, 2011 at 22:31

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