The Land of Day and Night, a physically impossible world.

[ThinkerX]

I have an SF world like this. A lost colony world thousands of years in the future.

I believe one of Ankari's worlds is like this, judging from some of the races he's posted.

Astronomically, a world like this would most likely be found orbiting an M class 'Red Dwarf'. Most Red Dwarfs have well under 1% the luminosity of our sun, though some check in with 2 - 3% solar luminosity.

Likely, such a planet would be orbiting close in to its primary, with a year equal to just a few earth months...probably 100 days max, in which case the whole world would be a bit chilly - even the day side. The sun of such a world, being closer, would appear far larger to that worlds inhabitants.

Even orbiting close in, ambient light levels on a world like this would be much less than daylight here on earth. Closest comparisions would be either a very heavy overcast or twilight. Even normal people on such a world would have better...night vision (low light vision?) than we do here. To them, a normal sunny day on earth would be literally blinding, even for daysiders. Plants would likely have larger and darker leaves, to better absorb solar energy.

Many M class stars are a bit unstable, prone to huge solar flares which can sometimes double their luminosity. This would have profound affects on the worlds weather, likely induce mutations among the local lifeforms, disrupt unshielded electronics, and in a fantasy world, likely have a severe effect on magic (perhaps magicians are born during times of great solar flares). It is possible the larger solar flares might actually be seen from the worlds darkside.

Moons for such a world are unlikely. If such a moon does exist, it is probably a captured object in an unstable orbit (sometimes very close to the planet, sometimes very far out).

As pointed out there would also be strong winds in the 'twilight' area, which would also serve to level out temperatures a bit, warming up much of the nightside to near tolorable levels.

 

[psychotick]

Hi,

There's some questions for me as well. If the world is basically day and night, i.e. it doesn't spin then you end up with a world in two parts, day and night as you describe. The band between them wouldn't have a day night cycle, it'd just be a perpetual twilight. But that's if its a sci fi book. If it's fantasy you could do it another way. The dark land is dark because some great spell brought the great black clouds to cover the land and stole the light. Not sure what sort of spell you'd so to have part ofthe world bathed in perpetual light.

However there are still things to consider. The dark side is going to freeze. That means as someone said no free water. Only ice. Plants are going to die, they need light and free water to grow. No plants, no herbivores. No herbivores and predators starve. So basically no ecology. The bright side of course burns and again there's no free water. No plants can grow and there's no ecology. But everywhere else if its normal and days continue as they are, life carries on.

My thought would be don't make it half the world in darkness half in light. Make it just a dark realm perpetually covered in black clouds, and then you can have your darklanders emerging from it to steal water nd food without having to travel thousands of miles. Likewise your lightlanders can do the same.

Cheers, Greg.

 

[Steerpike]

The planet could be spinning, it's just that the spin would have to be timed in relation to its orbit so that the same side is always facing the sun.

I don't know that the dark side would necessarily have to freeze. What if there was some kind of geothermal of volcanic process going on over there that kept the temperature within a range hospitable for life? You could have all kinds of interesting chemotrophic life evolve there.

 

[ThinkerX]

The dark side would be really cold...but not as cold as you might think, due to...atmospheric transfer of heat... strong winds crossing from the day side to the night side, bringing warmer air with them.

And yes, the planet could rotate, and provide a day/night cycle of sorts, provided it orbited almost 'pole on' (axial tilt of something like 80 degrees).

 

[Mythopoet]

Why on earth would a fantasy world need to conform to real world logic? It only has to conform to it's own logic. Give some thought to the nature and workings of your world. Make it internally consistent. Make sure you could give a good reason for something other than "It's magic!" or "I thought it would be cool" if someone asks you how something works.

I also write in a world where there are areas of light and areas of darkness and areas in between of twilight. I know why it is like that and how it works and most importantly why humans can still live and thrive in such a world.

This is what fantasy is all about.

 

[Scribble]

Here are some scientific speculations about how Earth would be like if it became "tidally locked".

Dark Side of the Earth: What would happen if our planet became tidally locked?

This is not to dump science on the story, but rather to stir ideas for factors that would prevent some of the aspects of extreme temperature that would make life a challenge on such a planet. Maybe you can world-build just enough mechanisms, possibly mystical, to stabilize things to satisfy the occasional science geek who would want to poke holes in the logic.

Those mechanisms that preserve life, if threatened, could even be a part of the story...

But, not necessary. As Mythopoet said, it's fantasy. Let it be fantastical if you wish.