Astrophysics worldbuilding question

[PallonianFire he/him]

Hey all, I'm well into a new novel and things are chugging along nicely. But I need to figure out a major worldbuilding aspect for this before I get going on the next chapter.

Basically, the main conceit of this whole story is that the kingdom it (mostly) takes place in has a black sky. I figure there are two ways to deal with this:

1) Tidally locked, a la Taldain. This has the problem of how life could be sustained on both sides of the planet. Or,

2) The planet has a ring. Black, of course. I'm more partial to this, but I can't find anything on whether or not rings are geographically locked. I.e. would it always be in the same spot of the sky? Could I get away with claiming that most of the sky for one part of a continent is black because the ring is always above them?

I know there are a bunch of smart people here, with a lot more knowledge of how these things work than I have. Any help would be appreciated!

EDIT: Problem solved! Just had an awesome brain wave that tied together my existing magic system, the black sky, and a great plot twist for 2/3 through. Off to revise the outline...

Edited January 3, 2017 by PallonianFire

[aeromancer he/him]

No on the ring. Running through all the calculation takes time, but essentially, you won't be able to get a big enough ring to black out part of the planet without blacking out the whole thing unless you want to deal with a whole host of other problems. Problems: a) not blacking out the entire planet, and choking the planet from life. Even using a single hemisphere rings leads to more problems as: b ) The 23.5 axis degree tilt would require an insane margin, assuming a single ring can cover the entire view of a single hemisphere, which could be corrected by removing the tilt, but then you lose seasons, and c) the gravity calculations are staggering. Rings is a bad idea.

Tidally locked sounds fine, but then you have (as you mentioned) problems arriving from lack of sunlight, as well as losing seasons. It's a bad idea.

So, how about a thick, Venus-like atmosphere? A very dense atmospheric cloud that blocks sunlight, but has a built in ecosystem that gets the solar nutrients to the soil, somehow. This would require a lot of work, but I'd be willing to go in greater detail should you want it.

[Hemalurgic Headshot he/him]

How about the sky is a hoax? The entire kingdom is overshadowed by a large object that blocks out sunlight. Having a fake sky could lead to some interesting plot aspects latter, if you want to. And if flora is a problem, remember chemosynthesis. Life can supported without sunlight. I hope you find something that works out.

[+Slowswift]

Isn't the sky's color caused by the chemical makeup of the atmosphere? You could probably do something with that.

[PallonianFire he/him]

Hmmm, lots to consider here. Thanks, guys!

[Eagle of the Forest Path he/him]

4 hours ago, Slowswift said:

Isn't the sky's color caused by the chemical makeup of the atmosphere? You could probably do something with that.

Here's NASA's explanation of why the sky is blue: http://spaceplace.nasa.gov/blue-sky/en/

I suppose an atmosphere with a different chemical makeup could diffract the light differently, but if you want a planet that can sustain (human) life I imagine the margins you can play with on that won't allow for a large color difference.

My first idea on Black Sky would be to have the kingdom under a constant solar eclipse, but that doesn't really work... well, maybe if that entire latitude is under the eclipse?... hmm.