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? > > > >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. > is there such a thing as a Dyson ring? I thought it was a Niven ring, as > per Ringworld, Ringworld Engineers etc. and as (fans of) those books > pointed out, rings are unstable no matter what.
I just made that term up as it seems to accurately describe it. But the term Niven Ring was invented first (I've just read the Wikipedia pages about his books). > 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. > short version is that gravity is a harsh mistress, often chaotic, and > hard to do right over long timescales. do you think the solar system > is stable? you are wrong. satellites? nope. but depends upon what > timescales they drift/resonate. https://en.wikipedia.org/wiki/Klemperer_rosette The Klemperer Rosette is also interesting. > I mostly know about high N N-body codes, but I have a symplectic toy > low N multi-timestep python code that I wrote somewhere. there are probably > high performance (giga-year) public symplectic low N codes out there too. > > BTW all mine are collisionless. quite different to David Zuccaro's > (intriguing - asteroid field?) collisional code. https://en.wikipedia.org/wiki/Alastair_Reynolds Alastair Reynolds Revelation Space series features a system that had a huge number of inhabited satellites that all collided after an alien virus destroyed their computers. NB this isn't a spoiler as that collapse isn't covered in his novels. His novel set before the collapse was published long after novels set after it which mention it in passing. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ _______________________________________________ luv-main mailing list [email protected] https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-main
