Re: Orbital simulation

[Craig Sanders via luv-main]

On Mon, Sep 26, 2016 at 01:46:29PM +1000, Paul van den Bergen wrote:
> the biggest drawback for both the Niven ring and the Dyson sphere is
> there is no gravitational attraction inside the ring or sphere to the
> sphere - only towards the sun, or only on the outside

i'm surprised that nobody's mentioned Culture Orbitals yet.

https://en.wikipedia.org/wiki/Orbital_%28The_Culture%29

they're much smaller than a niven ring, they orbit a star (and rotate
independently) rather than encircle it - slightly tilted to get a day/night
cycle as the orbital rotates.  They have an AI Mind located at the "hub"


craig

ps: i want the culture to come rescue us humans - and our world - from
capitalism. also want neural laces, mind backups, body changing, robot
bodies, utopian technosocialism, AI ships with great names, and more.
after 40+ years of reading science fiction, the culture is the first SF
universe I actually want to live in.

--
craig sanders 
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Re: Orbital simulation

[Ray via luv-main]

On 23.09.2016 13:59, Russell Coker via luv-main wrote:

Is there a good free orbital simulator for Linux?

I don't want a game like KSP but a simulation of orbits without much
need for fancy graphics.

I am wondering what the orbit of a ring would be like (EG a Dyson
ring) and whether it's plausible to make such a ring or whether a set
of disconnected sattelites in the same orbit is required.


While this is not what you are looking for xephem can calcualte and show 
the orbits of satelites of earth as well as orbital calculations for the 
planets. The graphics are not very flash, the program being now 
something like 26 years old, but it is designed to be accurate and be 
used as a professional tool. The program itself has a wide range of 
facilties having both text and graphical displays and can directly 
control a telescope.


There's no debian package for it, the program only being freely 
downloadable for none comercial use. I have though so far have ha no 
difficulty at all in compiling it. I noticed (just) now though there is 
a post about compiling it on debian 8. There are more flashy programs 
around now but none are so flexible and accurate as xephem.


Lindsay
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Re: Orbital simulation

[Rohan McLeod via luv-main]

Russell Coker via luv-main wrote:
> On Sunday, 25 September 2016 12:34:12 PM AEST Robin Humble via luv-main wrote:
>> On Fri, Sep 23, 2016 at 01:59:16PM +1000, Russell Coker via luv-main wrote:
>>> Is there a good free orbital simulator for Linux?
>>> ..snip
>> a full Dyson sphere is neutrally/meta stable, but no idea how you'd
>> actually construct it in a stable manner... likely someone has thought
>> about it though!
> https://en.wikipedia.org/wiki/Ringworld
>
> One thing that's noted in the Errors section of the above page is that a 
> ringworld as a rigid structure is not in orbit around the star but spinning 
> independently and would need attitude jets to keep it in place.  A full Dyson 
> sphere would require the same but with greater complexity as the jets could 
> only be on the outside of the sphere.

No doubt this is correct, but it is not intuitive;
- "intuitively" one might expect that movement of the centre of mass of
either:
the Ringworld or the Dyson Sphere away from the centre of mass of it's 
star;
would result in a net gravitational force and thus dynamic stability ?

regards Rohan McLeod

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