Bibliography for Ringworld series

They're fiction, of course, but Bob Shaw's 'Orbitsville' books (two of
them, I think) tackle this subject.

....which has just jogged my memory. Doesn't the Orbitsville sphere
suffer a very similar ultimate fate to the Ring? It's years since I've
read it (and I've only just finished 'Children'), but I'm sure that's
the case.

....and another memory-jog! The second book is called 'Orbitsville
Departure', of course - which I think confirms it.


On 30 Sep 2005 11:46:06 -0700, "Michael Mol" <mikemol.TakeThisOut@gmail.com>
wrote:

>Does anyone know the books and papers Larry Niven used in research for
>the Ringworld series of books?
>
>A friend and I are doing a lot of armchair theorizing about Dyson
>spheres, and we haven't found a lot of non-fiction reading to follow up
>on. So far, we found Freeman Dyson's original paper, "Search for
>Artificial Stellar Sources of Infrared Radiation", on microfilm, and
>Niven's own "Bigger than Worlds", but not much else.
>
>Please CC to my email address.
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Star <starsailor DeleteThis @nospam.freeuk.com> wrote:
> They're fiction, of course, but Bob Shaw's 'Orbitsville' books (two of
> them, I think) tackle this subject.

THREE of them:
Orbitsville (1975)
Orbitsville departure (1983)
Orbitsville judgement (1990)

> ...and another memory-jog! The second book is called 'Orbitsville
> Departure', of course - which I think confirms it.

That is just because the leading persons go out to search for other
groups/races to be transported TO Orbitsville.
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In article <gupvj1l5k8evf845nk40lfqas7t8ngeer9.TakeThisOut@4ax.com>, Star wrote:
> suffer a very similar ultimate fate to the Ring? It's years since I've
[SNIP]
> ....and another memory-jog! The second book is called 'Orbitsville
> Departure', of course - which I think confirms it.
>
Hmmm, is a Dyson sphere unstable in the same sense as a
RingWorld? I can't do the maths, but it seems plausible to me. Whic
suggests the need for considerable stiffening on the inside of a Dyson
sphere, serving a similar function to the Rim Mountains of RingWorld
(viz orbit-parallel stiffening ribs 1000 miles high).

--
Aidan Karley,
Aberdeen, Scotland,
Location: +57°10' , -02°09' (sub-tropical Aberdeen), 0.021233
Written at Mon, 03 Oct 2005 05:03 +0100
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Aidan Karley wrote:

> Hmmm, is a Dyson sphere unstable in the same sense as a
> RingWorld? I can't do the maths, but it seems plausible to me.

A Dyson shell (that is, a solid Dyson sphere) and a Niven ring are both
unstable. The Niven ring is actually actively unstable -- meaning that
there is an antirestoring force -- whereas the Dyson shell is only
neutrally unstable -- meaning that there is no restoring force. Both,
subject to perturbations, will destroy themselves; the Niven ring will
just do it more quickly.

> Whic
> suggests the need for considerable stiffening on the inside of a Dyson
> sphere, serving a similar function to the Rim Mountains of RingWorld
> (viz orbit-parallel stiffening ribs 1000 miles high).

The structural integrity of a Niven ring has nothing to do with the rim
walls; it's tensile stress in the floor material. For a Dyson shell,
it's just the opposite: it's compression stress in the shell material.
Putting up "stiffening" ribs doesn't do any good. (The rim walls in a
Niven ring are there to hold the atmosphere in, nothing more.)

--
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In article <4vCdnQRcqcwHQd3eRVn-iw.TakeThisOut@speakeasy.net>, Erik Max Francis wrote:
> The structural integrity of a Niven ring has nothing to do with the rim
> walls; it's tensile stress in the floor material.
>
Oh yeah. Suspension bridge with no ends.
> For a Dyson shell,
> it's just the opposite: it's compression stress in the shell material.
> Putting up "stiffening" ribs doesn't do any good.
>
For low rotation speeds. Actually there should be a neutral
rotation speed where the shell goes from being in compression to being in
tension. Have to watch that when you're spinning the thing up, unless you
want to build it spinning already. (Just to make life more difficult.)
Hang on, for the Dyson shell, the critical rotation speed will vary
with latitude. So ... If you're spinning it up, wouldn't your equator go
floppy, followed by a band of two latitudes progressing up to the poles.
That'd be pretty if you had a material that changed colour as it went from
compression to tension (why not, more exotic materials <G>).

--
Aidan Karley,
Aberdeen, Scotland,
Location: +57°10' , -02°09' (sub-tropical Aberdeen), 0.021233
Written at Mon, 03 Oct 2005 11:07 +0100
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Aidan Karley wrote:

> For low rotation speeds. Actually there should be a neutral
> rotation speed where the shell goes from being in compression to being in
> tension. Have to watch that when you're spinning the thing up, unless you
> want to build it spinning already. (Just to make life more difficult.)
> Hang on, for the Dyson shell, the critical rotation speed will vary
> with latitude. So ... If you're spinning it up, wouldn't your equator go
> floppy, followed by a band of two latitudes progressing up to the poles.
> That'd be pretty if you had a material that changed colour as it went from
> compression to tension (why not, more exotic materials <G>).

Yes. That's why you don't spin Dyson shells at all. A spun Dyson shell
leaves high lattitudes in vacuum. The thought experiment involving
spinning a Dyson shell for gravity is what leads directly to the design
for a Niven ring, as Niven pointed out in _Bigger Than Worlds_.

--
Erik Max Francis && max RemoveThis @alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
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>even though it's never mentioned in the books...

One thing that's always worth bearing in mind is that most of what we
know about the ring comes from character dialogue, and could therefore
be mistaken or deliberately misleading (a Niven character, telling
lies? Surely not...)

Phil Hibbs.
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In article <IZSdnfPXv_wYP9zeRVn-sg DeleteThis @speakeasy.net>, Erik Max Francis wrote:
> The thought experiment involving
> spinning a Dyson shell for gravity is what leads directly to the design
> for a Niven ring, as Niven pointed out in _Bigger Than Worlds_.
>
Ah, "Bigger than Worlds" has TTBOMK not been published on this side
of the pond (while I've been aware of Niven).

--
Aidan Karley,
Aberdeen, Scotland,
Location: +57°10' , -02°09' (sub-tropical Aberdeen), 0.021233
Written at Tue, 04 Oct 2005 08:46 +0100
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Erik Max Francis wrote:
>
<snippety>
> The structural integrity of a Niven ring has nothing to do with the rim
> walls; it's tensile stress in the floor material.

No argument with the last part of your statement - but (even though it's
never mentioned in the books), surely it's reasonable to assume that the
walls *would* have an effect on rigidity?

--

Bernie Dwyer
There are no 'z' in my email address
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In article <Av-dnbNdrb2nZdzeRVn-uQ.RemoveThis@speakeasy.net>, Erik Max Francis wrote:
> they're just there to hold
> in the atmosphere. For one thing, if that was their role, they wouldn't
> taper off to their top.
>
Hmmm.
The air pressure at the bottom of the RingWorld's atmosphere is
around 1 bar. Which can be held in with millimeters of rubberised fabric.
Even given the RingWorld Engineer's ("Proserpina may have been lying")
propensity for over-engineering things ... 40 miles thickness of /scrith/
suggests there's something else. Machinery spaces, possible ; but the
resistance to buckling implicit at the edges is going to be substantial.

RingWorld is around a million miles wide, at an "orbital" radius of
about 93 million miles. So the difference in distance between the primary
and, respectively, the centre of the Ring and the Rim Mountains is going to
be sqrt[sq(93*10^6) + sq(0.5*10^6)]-93*10^6 = 1344miles , or a factor of
1.44 * 10^-5. That's going to make for a buckling load on the rim edges.
How much, I don't know.

--
Aidan Karley,
Aberdeen, Scotland,
Location: +57°10' , -02°09' (sub-tropical Aberdeen), 0.021233
Written at Tue, 04 Oct 2005 09:05 +0100
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Bernie Dwyer wrote:

> No argument with the last part of your statement - but (even though it's
> never mentioned in the books), surely it's reasonable to assume that the
> walls *would* have an effect on rigidity?

A negligible one. First, remember that the rim walls are not there for
structural strengthening in the first place; they're just there to hold
in the atmosphere. For one thing, if that was their role, they wouldn't
taper off to their top.

Second, the main structural load is going to be a tensile stress on the
Niven ring floor material. This will also exert a tensile stress in the
rim walls (along their whole length), but the vast majority of the
structural load will be on the floor material.

--
Erik Max Francis && max.DeleteThis@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
There are defeats more triumphant than victories.
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Aidan Karley wrote:

> The air pressure at the bottom of the RingWorld's atmosphere is
> around 1 bar. Which can be held in with millimeters of rubberised fabric.
> Even given the RingWorld Engineer's ("Proserpina may have been lying")
> propensity for over-engineering things ... 40 miles thickness of /scrith/
> suggests there's something else. Machinery spaces, possible ; but the
> resistance to buckling implicit at the edges is going to be substantial.
>
> RingWorld is around a million miles wide, at an "orbital" radius of
> about 93 million miles. So the difference in distance between the primary
> and, respectively, the centre of the Ring and the Rim Mountains is going to
> be sqrt[sq(93*10^6) + sq(0.5*10^6)]-93*10^6 = 1344miles , or a factor of
> 1.44 * 10^-5. That's going to make for a buckling load on the rim edges.
> How much, I don't know.

The tensile stress induced in a Niven ring is from "centrifugal force,"
not air pressure. The air pressure is a measily 10^5 Pa at the surface.
The tensile stress induced in the ring foundation material due to its
rotation is ~10^17 Pa. The two are simply not comparable.

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Erik Max Francis && max RemoveThis @alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
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JRS: In article <VA.0000097e.4f8dcf0f.DeleteThis@validemailaddresstoa.news.group>,
dated Tue, 4 Oct 2005 11:00:36, seen in news:alt.books.larry-niven,
Aidan Karley <doIlookDAFTenoughTOpost.DeleteThis@validEMAILaddressTOa.NEWS.group>
posted :
>In article <IZSdnfPXv_wYP9zeRVn-sg.DeleteThis@speakeasy.net>, Erik Max Francis wrote:
>> The thought experiment involving
>> spinning a Dyson shell for gravity is what leads directly to the design
>> for a Niven ring, as Niven pointed out in _Bigger Than Worlds_.
>>
> Ah, "Bigger than Worlds" has TTBOMK not been published on this side
>of the pond (while I've been aware of Niven).

Note : it's not a book, but a non-fiction article. It's in Niven's "A
Hole in Space", which is largely short stories, UK edition; and in
Pournelle's "The Endless Frontier" collection (my copy is US).

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