# The Ringworld is unstable! **URL:** \ **Category:** Cafe Society\ **Created:** [July 27, 2018, 9:35pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703 "2018-07-27T21:35:35Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [July 28, 2018, 3:07pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/21 "2018-07-28T15:07:59Z")
To add on to my last post, if a species has the ability to turn iron into scrith on a global scale, (which is beyond anything seen in any Known Space species), wouldn’t they also have reactionless drive? Using Bussard ram jets for stability seems so crude. Other than the unobtanium they are using for the structure, the ring is “analog” tech. Brute force. Giant bulldozers moving mud. Stepping discs would work infinitely better than giant pipes dumping mud in the mountains. Solar flares for defense is right up there with throwing rocks at invaders. The system cannot respond quickly. It would take hours if not days to force solar flares using magical superconducting coils in the ring. Good for rogue asteroids, useless against invading ships. Plus it appears to not care if it shoots the ring itself! A serious design flaw. Niven should have had the ring made out of paper stabilized with a stasis field. That would have solved almost every problem (except Fist of god, so he’d have to come up with another solution.). ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 28, 2018, 3:19pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/22 "2018-07-28T15:19:49Z")
As in all of Niven, the answer is: _The Outsiders did it._ ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [July 28, 2018, 3:54pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/23 "2018-07-28T15:54:25Z")
I never cared much for Molly Ringworld as an actress. (I’ll let myself out.) ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [July 28, 2018, 4:03pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/24 "2018-07-28T16:03:18Z")
> [@burpo\_the\_wonder\_mutt](#): > > I never cared much for Molly Ringworld as an actress. > > (I’ll let myself out.) She’s fairly stable, though. ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [July 28, 2018, 4:26pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/25 "2018-07-28T16:26:09Z")
😉 😃 ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 28, 2018, 5:35pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/26 "2018-07-28T17:35:43Z")
> [@Just\_Asking\_Questions](#): > > The book also made the myth of hyperspace creatures that eat spaceships into a reality, so the whole book should be tossed. > > Can an author screw up his own universe so much that his own books should be removed from canon? He contemplated [going whole hog](http://www.larryniven.net/stories/downinflames.shtml). BTW, I really enjoyed the recent [Ringworld prequel pentology](https://en.wikipedia.org/wiki/Fleet_of_Worlds), if any of you aren’t familiar with it. (I also enjoyed it if you are familiar with it–it isn’t a quantum cat thing.) ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [July 28, 2018, 10:04pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/27 "2018-07-28T22:04:05Z")
> [@Darren\_Garrison](#): > > BTW, I really enjoyed the recent [Ringworld prequel pentology](https://en.wikipedia.org/wiki/Fleet_of_Worlds), if any of you aren’t familiar with it. (I also enjoyed it if you are familiar with it–it isn’t a quantum cat thing.) I skipped Fate of Worlds, for obvious reasons, but the other four were good. ---
**Author:** ![Gray\_Ghost](https://avatars.discourse-cdn.com/v4/letter/g/c0e974/32.png) [@Gray\_Ghost](https://boards.straightdope.com/u/Gray_Ghost)\ **Post date:** [July 28, 2018, 11:07pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/28 "2018-07-28T23:07:49Z")
> [@Just\_Asking\_Questions](#): > > I skipped Fate of Worlds, for obvious reasons, but the other four were good. There was some real inconsistency in how he wrote the Pak over all the books. In some, they’re absolutely unstoppable physically, technologically, and mentally, and always come up with the most efficient solution in the least amount of time. In others, they grab the Idiot Ball and practically sprint with it. I liked all of the stories, and even Ringworld’s Children, even as the physics got even sillier. More Known Space stories are usually better than fewer. The glimpses at Puppeteer society were pretty neat too. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 28, 2018, 11:59pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/29 "2018-07-28T23:59:15Z")
I’ve got _Fleet of Worlds_ lying around here somewhere; it’s probably coming up pretty soon on my “read next” list. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [July 29, 2018, 1:02am UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/30 "2018-07-29T01:02:48Z")
Meh. I read the first of the prequels and gave it up. I really hate it when an author is so out of ideas that he/she stripmines previous works looking for some overlooked piece of sellable dross. You’re rich, Larry! Give it up and just relax, why don’t you? ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [July 29, 2018, 1:34am UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/31 "2018-07-29T01:34:12Z")
Speaking of Known Space stories, some of the Man Kzin War books are OK. Related to this thread, there is one story where the protagonist finds himself dumped in some giant structure like an alien menagerie, with several species of large furry animals trapped together (but not grooving, at least at first. 🙂 ) It’s another impossible structure, like Ringworld, with no indication of who built it, or why, and no answers forthcoming. Mysteries are OK, if they at least give some indication that they can be solved. But this structure would have required yet another super-powerful yet vanished species in known space. ---
**Author:** ![Gray\_Ghost](https://avatars.discourse-cdn.com/v4/letter/g/c0e974/32.png) [@Gray\_Ghost](https://boards.straightdope.com/u/Gray_Ghost)\ **Post date:** [July 29, 2018, 2:17am UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/32 "2018-07-29T02:17:30Z")
That one sounds like Cathouse and it’s sequel, from Dean Ing. IIRC, the protagonist guessed that the Outsiders (per **beowulff/** ) built Zoo. ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [July 29, 2018, 6:30am UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/33 "2018-07-29T06:30:32Z")
> [@Gray\_Ghost](#): > > That one sounds like Cathouse and it’s sequel, from Dean Ing. IIRC, the protagonist guessed that the Outsiders (per **beowulff/** ) built Zoo. Like Beowulff (hmm, I suspect a knowledgable Know Space expert…) anyone would _suspect_ the Outsiders. I would expect an author to actually \*answer \*the question. 🙂 Otherwise it’s just mental masturbation. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [July 29, 2018, 9:05am UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/34 "2018-07-29T09:05:39Z")
Not only is the Ringworld unstable, but it took less than a year from the publication of the novel to discover this. It was at the 1971 Worldcon that the students chanting “The Ringworld is unstable” happened. The instability would cause it to drift away fairly quickly. If it was one meter away from the correct position, in 55 days it would be two meters off, in another 55 days it would be four meters off, etc. This is a paper showing this instability using not terribly difficult math: > **[ringworld.pdf](https://www.brannenworks.com/GE253/ringworld.pdf)** > > 127.99 KB ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [July 29, 2018, 12:21pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/35 "2018-07-29T12:21:37Z")
> [@Wendell\_Wagner](#): > > Not only is the Ringworld unstable, but it took less than a year from the publication of the novel to discover this. It was at the 1971 Worldcon that the students chanting “The Ringworld is unstable” happened. The instability would cause it to drift away fairly quickly. If it was one meter away from the correct position, in 55 days it would be two meters off, in another 55 days it would be four meters off, etc. This is a paper showing this instability using not terribly difficult math: > > [http://www.brannenworks.com/GE253/ringworld.pdf](http://www.brannenworks.com/GE253/ringworld.pdf) I’m pleased to see that this comes up with the same number (55 days) as I had above (well, I said 8 weeks, but that’s a round-off error). ---
**Author:** ![furryman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/furryman/32/99_2.png) [@furryman](https://boards.straightdope.com/u/furryman)\ **Post date:** [July 30, 2018, 6:16pm UTC](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703/36 "2018-07-30T18:16:08Z")
> [@burpo\_the\_wonder\_mutt](#): > > I never cared much for Molly Ringworld as an actress. > > (I’ll let myself out.) I loved that trilogy The Lord of the Ringworld. [Previous page](https://boards.straightdope.com/t/the-ringworld-is-unstable/818703.md?page=1)