Comments on: With This Ringworld I… Do What, Exactly?

By: Hentzau

Hentzau — Sun, 23 Jun 2013 10:01:48 +0000

Ha, yes. Banks was always good at making his magical future science come with realistic catches.

By: Everblue

Everblue — Fri, 21 Jun 2013 11:49:50 +0000

One of my favourite things in any Sci-Fi book ever was the bit on the ringworld in Consider Phlebas when the kid with the AG harness falls to his death, because there’s no gravity on the ringworld – just simulated gravity due to a rotating frame of reference.

That absolutely blew my mind.

By: Gap Gen

Gap Gen — Thu, 20 Jun 2013 11:58:50 +0000

Oh but apparently they do contain M101, according to the Wikipedia page’s image.

By: Gap Gen

Gap Gen — Thu, 20 Jun 2013 11:57:32 +0000

They’re not centred on stars, nope (insofar as a fictional structure in not-very-hard scifi is anything) – http://en.wikipedia.org/wiki/Orbital_%28The_Culture%29

Depends on the Lagrangian (plus I guess, sure, even a technically stable one rather than a saddle point one would eventually drift?), but yeah, putting something planet-sized on it might tip out of the stability zone.

By: Hentzau

Hentzau — Wed, 19 Jun 2013 17:44:49 +0000

I kid, I kid. But yeah the maximum surface area for a given quantity of material would actually be the outside surface of a hollow sphere. I think.

By: Hentzau

Hentzau — Wed, 19 Jun 2013 17:42:53 +0000

what

By: Hentzau

Hentzau — Wed, 19 Jun 2013 17:42:24 +0000

I thought Culture orbitals were centred on stars? Halo definitely isn’t; it orbits between a gas giant and its moon on one of the Lagrangians. Lagrangians, as we have already covered, are actually not all that stable at all, and especially not for bodies on the scale of the Halo. So yeah, keeping it stable would require engines of some kind.

By: Hentzau

Hentzau — Wed, 19 Jun 2013 17:39:07 +0000

Problem with that idea is that this is exactly why the Sentinels exist: to maintain Forerunner constructs. They all seem to be running perfectly fine after millions of years, so there’s no reason to think artificial gravity systems wouldn’t either.

(The atmosphere thing is interesting, because it almost certainly couldn’t maintain an atmosphere if it wasn’t being constantly replenished somehow.)

By: Adam Benton

Adam Benton — Wed, 19 Jun 2013 11:13:10 +0000

Also, in Halo the guys who made it promptly activated it and all died. Perhaps they wanted something that would naturally generate gravity so there wouldn’t be complicated machines involved that could break down and fail after they’d died. However, I suspect that the rubg world couldn’t maintain an atmosphere, so they might need machines for that which of negates this idea. Or could it maintain it?

By: Gap Gen

Gap Gen — Wed, 19 Jun 2013 11:04:02 +0000

Note that the Culture orbitals and (I think) the Halo differ from Niven’s Ringworld in that the latter is centred on the star, while the former orbit the star like a planet, with a small inclination so that it has a night/day cycle as it rotates.