Could (and how would) life develop and survive in a place of 24 hours of darkness?

Question

In my fantasy world, Ghafir's Spear is known by many to be a place without light. Here, there is no light, and darkness dominates the land. Despite its shadow, however, there is life here, including humans in the city of Ardam.

I am thinking of a setting where part of Earth is dark 24/7. However, I encountered a problem where I need to have life (including humans, though this one is optional) thrive with little to no sunlight. Let's just say night lasts about 19 hours, 2.5 hours of morning, 2.5 hours of dusk, and no noon.

Is life in such place scientifically feasible?

What kind of animals and plants would live in such place? Could the regular deers and trees and crops live here?

How would a human survive here? If a human stayed here for long periods of time would there be terrible effects should they see sunlight in the outside world?

If it happens to not be scientifically feasible, how about a place where it is misty 24 hours a day? Can life thrive here?

Edit: Thank you everyone! In advance as well. I appreciate your answers!

Answer 1

Plants

With five hours of indirect sunlight (dusk/dawn), there are few plants that would survive long-term. Many plants (including most food crops) depend on photosynthesis. Thus, your people probably aren't going to be eating a lot of home-grown wheat bread. However, there are a lot of edible plants, roots, and herbs that will grow in low light levels.

Animals will be similarly challenged. They either eat plants, or they eat other animals that eat plants. In other words, animals would have a tough time, too, if they are confined to the dark area.

Weather

Without direct sunlight, if the region is small, its weather will be dominated by warm air (and possibly water) currents from outside regions. If the region is very large, it could get quite cold indeed. If that's the case, the cold temperatures will obviously present additional challenges to plant and animal survival.

What about humans?

Since your humans named something "Ghafir's Spear", I'm assuming they have at least discovered basic tool-making (spears). Such humans would probably have good survival prospects, and would develop the skills to adapt to a dark environment reasonably well. That would probably include "importing" food from beyond the dark border and/or cultivating low-light crops and animal herds.

On a physiological level, humans can survive in the dark just fine, as long as we have food, clean water, and can stay warm (in other words, the same requirements in sunlight!). Importantly, the same is true for many animals. The reason animals would die off would be because they lose access to food sources (or perhaps if the weather is too cold—see above).

If the animals can roam into "light" areas to hunt or graze or have help from the humans, most animal species could survive indefinitely, in spite of the dark. Given the choice, however, many animal species might migrate to areas with sunlight because the hunting/grazing is better there.

Vitamin D deficiency

Exposure to sunlight (specifically, UV-B radiation) on our skin actually causes our body to produce Vitamin D, which has beneficial effects. Your humans (and possibly some animal species) might experience some Vit-D-deficiency-related health problems, such as suppressed immune systems, depression, and bone diseases. However, they might find other (dietary) sources of vitamin D (even by accident), and the limited sunlight they get might be enough to produce sufficient vitamin D if they spent enough time outdoors.

What if the humans venture into the sunlight?

It depends how long they have been in the dark, but probably not much would happen to them. They might be dazzled by the sunlight, although indirect strong daylight isn't that much different than looking into the flames of a bright campfire. If an entire society has been isolated in the dark for many, many generations (I can't even guess at a reasonable number) with no outside genetic contribution, their eyes and skin (melanin) might have adapted somewhat—they'd likely be rather pale-skinned—but that would take quite some time, and exposure to sunlight still wouldn't be very harmful. At most they might suffer some temporary/partial blindness and a nasty sunburn if they don't take precautions. If they shield their eyes, wear long sleeves, and a wide-brimmed hat, they'll probably be fine.

Is such a place scientifically feasible?

As you describe it, no, not really. The closest we have on Earth: as you get nearer the poles on Earth, there will be days of the year where the sun never rises. However, it is necessarily the case that in the summer, the sun never sets.

I'll discuss some other options:

If you had a planet that was tidally locked with its star, there would be a dark side (night 100% of the time, almost certainly very cold), a light side (day 100% of the time, and probably very hot), and a middle zone that remains partially lit and warm-ish. However, I don't think that fits what you want, because the planet wouldn't have "days" in the conventional sense of sunrise/sunset at all, and your semi-dark "region" would be a geodesic ring around the entire planet.

You then asked about a perpetually "misty" region. While I don't have a good answer for you on how that might (realistically) be achieved, there are a number of ways you could have a "dark" region:

• Underground. Pretty obvious, so it's probable you've already thought of this and discarded it for some reason.
• Heavily forested. The advantage here is that it solves the plant/animal problem as there are many species adapted to live under the canopies of dense forests.
• Magic. You did list a "magic" tag, so your last resort is perhaps some powerful wizard (or whoever wears the magical pants in your story) who throws a spell/curse/etc. on the entire region, condemning the inhabitants to live in misty, shrouded darkness for 19 hours of the day.

Answer 2

I agree with type_outcast's answer although I think there are some points missed...

Bioluminescence is commonly associated with dark deep sea, serving many purposes aside from simple illumination - such as communication for instance. Yet it is not unique of the sea^1, since there are fungi, insects, arachnids and a few others small animals capable of bioluminescence - being fireflies probably the best well known example.

^1: various types of bateria, algae, fish, jellyfish, crustaceans, cephalopods, etc... have bioluminescence.

The ability to produce its own light would - obviously - be useful in a place of perpetual darkness - it makes it easy to find what to eat, and equally important it may play a role in mate selection.

There is a catch to that! if you use your light to attract your sexual partner, you are attracting predators too. I would expect this strategy to be only used by small animals that produce many offspring that overcompensate for the losses that naturally happen during their mating season - which I would expect has a low frequency, enough for no predator to sustain only from eating them.

On the other hand bioluminescence requires energy, and food is scarse, so while you should be able to find some examples in the dark regions... they wouldn't be the rule.

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Without sight, hunting wont be the task of fast predators that run behind a pack of herbivores. Instead other senses would develop to be more useful in darkness. And hunting tactics will have to adapt.

For instance acute olfactory organs are used by animals that expend most of their lifes underground - with little sunlight.

If tracking by smell is a good idea, rapine comes with it. Chemical tactics are also very effective, such as poisoning a victim, and track it while the poison takes effect and kills it... or a swarm of small animals may resource to inducing high pain and paralysis while they devour the victim alive. Prey animals may try to use fast discharges of fluid - cough urine cough - as defence mechanism when cornered.

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Another strategy of life in the dark is Echolocation, which is mostly known by bats - which is where it was discovered. Yet has been found in various other species such as the Tenrecs rats from Madagascar. Your dark regions can't trope be complete without them.

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We may also extend on the topic of animal eyes. The eyes of nocture animals may be bigger to allow more light in, would have relatively more rods in the retina allowing to differentiate smaller changes in illumination - in expense of cones, meaning that they have less color perception. Also a very common adaptation is the lucidum that used to reflect light internally in the eye to allow for a greater exposure - and also causes laser eyed cats.

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Another imporant topic is the Circadian rhythm if you still have a few hours of dusk/dawn it not really a problem for animals. Still it is a problem for plants that adapt their metabolism for day and night - that puts a cap on plant growth. And also in lack of seasonal changes there wouldn't be trigger for bloom. Moss, Ferns and others flowerless plants and known to be able to grow with minimal light can still thrive there. Aside from that, there are saprotrophic, mycoheterotrophic and parasitic plants that don't need light to grow - Monotropa uniflora comes to mind.

Regarding humans, when living underground - with aritifial light - people just sleeps whenever they feel like it, regardless of the daytime of which they are unaware of. People may still sync their sleep and eating patterns within small groups for social reasons.

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The problem with dietary sources of Vitamin D is that whatever you eat to get Vitamin D has to get Vitamin D from somewhere. For that I want to suggest Lichen which takes minerals from the rock on which it grows and is the main source of Vitamin D (if you want to go vegan, that is).

Finally, ragarding food sources for humans, Tubers are probably the best option for cultivation - with the help of some artificial light. Or use "magic". Also chances are you can invent some interesting fish adapted to darkness but not the high preasures of deep sea. Insects and small mammals would also be on the plate. Glow-in-the-dark rabbits anyone?

Answer 3

The thing that sunlight provides for life is energy, so that plants can conduct photosynthesis, and the entire ecosystem is built on that. If you had something other than the sun that could provide the energy that the plants need for photosynthesis, you could have a normal ecosystem there. In a fictional universe I created a long time ago, I had this one planet that had no access to external light(no sun, stars, moon, or anything else). The energy came from a material that was underground on the planet, which was tapped into by a plant-like species which lived off of it. Other creatures would then eat those creatures to survive.

Answer 4

To deal with a linguistic point first, you can't have anywhere with 2.5 hours of daylight but no noon, since noon is simply the middle of the period of daylight.

Kiruna in Sweden right now has 2.5 hours of daylight and probably a similar period of dusk, because it's close to the Arctic Circle and it's midwinter And there's life in Kiruna. The short period of daylight won't last long, of course. But if your planet has a similar axial tilt to the Earth but circles a very large star at a very large distance, it could have a much longer year so that the far north has an extended period of little daylight (or no daylight, within the Arctic Circle). Life would evolve to cope with it. Try reading the Helliconia trilogy by Brian Aldiss, which is set on a world like this.

You do have a problem. Very large stars have a very short life, not long enough for complex life to evolve on their planets.

Answer 5

If there's a way for your humans to create electricity - say, coal or tidal power or wind farms or something like that (that doesn't require light directly), then electric lights could be powered to sustain plant life on the planet, with the humans completely in control of its growth. However, I agree with the above points - if your planet is orbiting a star, then there will have to be somewhere on it that has sunlight. Perhaps you could set it on a planet really far out from the sun, though an issue with this is that there wouldn't be liquid water - a problem your humans could potentially deal with by creating heat by, as I said before, lightless energy sources.

Furthermore, a question that arises is exactly how was this planet inhabited? If they are colonists that knew about the planetary conditions beforehand, presumably they would have brought supplies with them and technology to deal with the extreme conditions. Evolution on such a planet, I do not think would be feasible at all, given the lack of sunlight.

If magic is involved, and only a certain region is affected, then your problem of planets and suns and biology is solved quite well and gives a rather obvious story to tell!