Planet: Xibalba (Mayan Hell)

Tidally locked planet around a red dwarf that is very active with solar flares being a daily danger.

The habitable zone around the planet is made up almost entirely of mountains, as is a large amount of the surface on the day and night side. There is a large ocean that covers much of the day side, and circles around to the dark side in the southern hemisphere.

The planet has a gravity 0.4 times higher than Earths.

The atmosphere is breathable after some adjustment, it is similar to Tibet for air pressure and oxygen content. The water is also drinkable with basic filtration.

Temperatures in the habitable zone at the foot of the mountains range between 4 degrees Celsius close to the dark side, to 25 degrees Celsius near the day side. These are rough averages, a lot depends on wind conditions, shade, etc.

Hurricanes are nearly continuous, causing heavy erosion on the mountains and turning valleys and plains into swamps. Some life is there, but it's mostly coral like and under water to protect itself from the UV flares.

Due to the heavy erosion and tectonic activity the mountains are riddled with caves. These caves have lots of coral and mollusk like plants that can photosynthesize while surviving the worst UV and hurricanes. This provides food for cave dwellers who spend most of their lives inside the extensive cave systems, creating a food chain further into the caves through their feces. Frequent floods also bring food and nutritious muck into the caves for bugs, fungus and bacteria to eat.

Water seeping through cracks form feeding spots for bacteria, mold and slime, which in turn are fed on by bugs, and are eaten by larger animals. Underground lakes and rivers, often fed by water from the surface and magma vents deep underground, provide life for fish, mollusks, crustaceans, worms, bacteria and thermophiles.

No animal is larger than a good size cat, but they often have poison and the predators will work in packs to get a meal.

Most animals rely on echolocation, thermal vision similar to pit vipers, electroreceptors, smell and touch.

The humans numbering two hundred, have some mining equipment, grow lights that with maintenance can last for decades with the ability to make more, and a large amount of survival equipment (clothes, sleeping bags, cots, tools, water purification systems, flashlights medical kits, etc).

For food they have a years supply of rations, several kinds of herbs, cabbage, cress, broccoli, beets, radishes, dandelions, carrots and sweet potatoes, these can grow in shade but take longer to grow and don't produce as much yield. For meat they have several types of edible beetles and chickens.

The humans will be close to the day side.

Is this enough for long term survival or are they doomed after a few years?

  • 2
    $\begingroup$ This is an environment where any colonist's motto should be: come well equipped. Not somewhere for the fainthearted. For adventure tourists only. Your two hundred seem singularly ill-equipped for Xibalba. Their chances of long-term survival aren't good. Why go there without adequate preparation? $\endgroup$ – a4android Mar 2 '18 at 6:14
  • 1
    $\begingroup$ @a4android, because their ramshackle space habitat broke due down due to lack of resupply from Earth, they had no choice but to grab what they could and land. The planet was only used by some scientists who were much better prepared and smaller in number. The system is basically seen as a place where useless people go when no other system will have them. $\endgroup$ – Dan Clarke Mar 2 '18 at 6:24
  • 1
    $\begingroup$ Glad you filled in the backstory which explains what is happening and why. Rendering my comment redundant. Personally I'm uncomfortable with the dumping misfits on hardship planets concept, but that's me. My guess is their long-term survival isn't good. Hope you get some good answers. $\endgroup$ – a4android Mar 2 '18 at 7:45
  • $\begingroup$ @a4android the answers have been great. The hardship planet dumping isn't intentional. The entire human race suffers a massive fall from grace and has to struggle to survive. An Arid planet is a hopeful story in the far future after humanity has largely recovered. A waterworld is an adventure story immediately proceeding the fall. This is a survival/horror one a few years after when people realize just how screwed they all are. $\endgroup$ – Dan Clarke Mar 2 '18 at 7:54
  • 1
    $\begingroup$ Thank you so much for not asking how they make weapons! Often it seems (and may be) that half the questions here on "worldbuilding" is how to shoot or blow up stuff. "In the future, what will we use to shoot each other?" is like the subtitle of this topic (stack?). $\endgroup$ – Hebekiah Mar 2 '18 at 8:10

Good news! You have a good chance of having a robust magnetic field and less wild temperature variation according to this study by Exoplanet Exploration. To survive the temp differential and not break up your planet must be good at dispelling heat as well, out the night side, evening temperatures somewhat and turbocharging a magnetic field. They even figured in a more active star and increased volcanism and found this a sufficient mechanism for protecting life from flaring radiation.

About the atmosphere, gravity and plant life. Higher gravity, lots of volcanoes so lots of gases ejected, why the thinner atmosphere? and since CO2 and other nasty volcano gases, you're going to require a bit more vegetation or mechanism for O2 production. But with a denser atmosphere perhaps no great need for as much O2 by percentage, merely enough to supply the colonists. It looks like you've thought about a nitrogen cycle but high levels of regular CO2, methane, etc, production from volcanism, you'd better have some good stuff in that ocean. Lack of abundant nitrogen though would explain a bit about lower atmospheric density and generally stunted life.

But about the colonists chances? If the planet is working so far it means it indeed has a healthy magnetic field and the solar flares won't be such a problem. I'm not sure how extensive long lasting cave systems mix with highly active tectonics...but skeptical. All the large cave systems I've visited, whether of volcanic or hydraulic origin, were in stable areas, not prone to earthquakes. For your whole system to work you're going to need to answer how the caves are stable amidst all that plate activity (I'm guessing).   I'm also thinking about needs for long term survival and stability, room for expansion and hope are important considerations. You've spoken of the challenges, difficulties, and dangers the planet affords; what about what is good about it? Finding something intriguing, even wonderful, that made the colonists feel hopeful and a sense of connection with the planet rather than it be nothing but a hostile enemy. While the animals may be quite dangerous to each other (poison), with such a distinct and tight ecosystem, none would identify the foreign colonists as enemy or pray, and even ignore them all together or permit close proximity (perhaps).

  • $\begingroup$ Excellent answer. I'll change my notes to fit some of it in. The mountains with the extensive caves are generally the older ones, the vents are mostly left overs from the mountains creations and in the deep aquafiers. So I need to ease off on the flares, improve the weather and tectonics a bit, a bit more outside life, and it becomes less of a last desperate gamble of survival and turns into an actual safe-ish haven. $\endgroup$ – Dan Clarke Mar 2 '18 at 7:15
  • 1
    $\begingroup$ Oh you'll have flares as the star type and planet suggest a young system, first 2 billion years. You've got that all correct. But with magnetic field and mountains for protection, life wouldn't be limited to the caves unless oldest, more advanced ecosystems are out of the raging storms you mentioned. Perhaps some meteor impacts also elevated the importance of cave life. Some good algae that use geothermal to produce oxygen? Don't get too down with people's "barren cave" stuff. Weird life in Yellowstone geyser ponds does exist & caves can have openings like skylights. It's sci-fi, have fun. $\endgroup$ – Hebekiah Mar 2 '18 at 7:47
  • $\begingroup$ That's the plan. I started out with an arid planet story along the lines of a hopeful early sci if story backed by science. Then I got a great idea for a water world for the same universe as an adventure story. And then his idea came along today for a darker tone in the series. Lots of fun designing things, even if with my muse running wild I need to fact check things more than usual. $\endgroup$ – Dan Clarke Mar 2 '18 at 7:55
  • 1
    $\begingroup$ You suggest this place isn't in an unknown area though regular contact is no longer occurring. Are the scientists still around, did they find anything great besides mating cycle of cave maggots? Is there anything at all special or cohesive about these people or likely to develop? With mining, farming and fabrication tech and abilities, plenty of potential power (always day of part of planet and geothermal, probably methane too) what are they going to do? More important who are they to be, what identity can they coalesce around since basically they were abandoned by Earth? $\endgroup$ – Hebekiah Mar 2 '18 at 8:03
  • 1
    $\begingroup$ I like it; gas miners have to figure out how to exploit the resources of an oddball planet in order to survive. I wonder how they can transfer Helium3 mining tech & knowledge to that of this planet? Caverns for gas reservoirs, refining techniques used to manipulate their environment and supply their needs. Volcanic vents to harvest from, everything they do affecting the balance on this delicate planet, solar flares giving ionized compounds...you've got some atmospheric research ahead! $\endgroup$ – Hebekiah Mar 2 '18 at 8:58

These caves have lots of coral and mollusk like plants that can photosynthesize while surviving the worst UV and hurricanes.

How can light reach the inner of caves? It will at best stop few meters after the cave entrance.

Water seeping through cracks form feeding spots for bacteria, mold and slime, which in turn are fed on by bugs, and are eaten by larger animals. Underground lakes and rivers, often fed by water from the surface and magma vents deep underground, provide life for fish, mollusks, crustaceans, worms, bacteria and thermophiles.

In the caves we know the food chain is much shorter. You can have some mollusks/crustacean or even amphibian, but to sustain a fish you need way more biomass. Caves have really limited energy intake, no much life can thrive on that.

For food they have a years supply of rations, several kinds of herbs, cabbage, cress, broccoli, beets, radishes, dandelions, carrots and sweet potatoes, these can grow in shade but take longer to grow and don't produce as much yield. For meat they have several types of edible beetles and chickens.

Again, I think you are overestimating the energy income on these caves. They are basically dark places, not shady ones, with some chemical energy dripping from above. You lack the light and the ground to grow plants. Not even mentioning that growing poultry requires even more biomass to sustain them.


Your humans will be doomed shortly after the year of supply they have is gone.

  • $\begingroup$ The Coral and molluscs are at and just outside the cave Mouths, not directly in the caves themselves. As for the human food, they have growing lights to set up hydroponics. And with the fish, there are fish in caves on earth that never see the surface. Even one species of crocodiles lives its adult life in a cave system in South Africa. $\endgroup$ – Dan Clarke Mar 2 '18 at 6:19
  • $\begingroup$ @DanClarke, even worse then. It's way less available surface, few square meters when the entire cave can span for kilometers... $\endgroup$ – L.Dutch - Reinstate Monica Mar 2 '18 at 6:21
  • 1
    $\begingroup$ OK, I can change things so that there are species that head out into the swamps for several hours to gorge and return to the safety of the caves. That will let more energy enter the cave systems. It will be like the guano from bats that feed insects and fungus on earth. $\endgroup$ – Dan Clarke Mar 2 '18 at 6:28

The very best place to survive is on board the spaceship orbiting the star. The starship's own life support systems will provide functional temperatures, breathable atmospheres and radiation protection.

enter image description here

This is the way you will be seeing the planet

The crew simply places the starship in a position where the planet is between them and the star, and using shuttles, a tether or other means mines the planet for materials to top up the systems. All that extra water is nice, and minerals can be used to charge the life support system with various elements which have been lost due to inefficiencies of the life support system.

Further mining can bring raw materials into orbit, which can then be heated to a plasma using a large solar mirror (really nothing more than a big aluminum foil sheet) in a separate "smelter" orbiting the star with no obstructions between the facility and the star. The plasma are then passed through a mass spectrometer to be separated by atomic mass and then deposited on cold traps. The crew now have the raw materials to feed into their 3D printers to build replacement parts for their starship.

enter image description here

Workings of a mass spectrometer

Even seemingly useless stuff becomes handy in space. Any slag materials becomes plating to increase the radiation shielding of the ship. If there is a lot, you can build large orbiting shelters out of it, and gradually fill it with water, soil and atmosphere to increase your living space and standard of living. If artificial gravity is a thing, new grav generators can be built and added, otherwise the shelters are rotated to create an artificial gravity.

enter image description here

more leg room for everyone

This may sound like a cheat, but consider if they have the skills and tools of a starship crew, it is far more efficient to use those tools to create their own environment in space, rather than spend excessive time and energy fighting the local environment attempting to make a livable habitat.

  • $\begingroup$ Agreed, which is why the planet isn't prepared for colonization and the main place to live was a generational space colony designed for several hundred thousand residents orbiting another planet in the system. However that doesn't lead to a survival story with horror elements as thousands of others who landed on other parts of the planet with less order and supplies try to survive by raiding and worse other better run refugee camps. $\endgroup$ – Dan Clarke Mar 2 '18 at 23:49
  • $\begingroup$ If that is my choice, I'm turning into a space pirate and raiding the generational space colony building site, for all the reasons listed in my post. $\endgroup$ – Thucydides Mar 3 '18 at 5:00
  • $\begingroup$ that's actually being used in another story in the same universe. There is a reason for the abandonment of the space colony that makes sense. It's a very last resort option after everything else has failed. $\endgroup$ – Dan Clarke Mar 3 '18 at 5:16
  • 1
    $\begingroup$ Once you can build a generational ship, actually using it to colonize a planets surface becomes sort of a moot point. The first state of any generation ship getting to it's destination, should be setting up space mining and manufacturing. Why would you bring all that mass down to the planet and then have to bring mass back up from the planet. It's better to start mining in space and build your way down to the surface, rather then land and build your way up. $\endgroup$ – ArtisticPhoenix Mar 4 '18 at 11:35
  • $\begingroup$ The only thing "special" a planet would have that you cant get easier in space (once you have a generation ship in space) is life native to that planet. Other then that, actually becoming a grounder is pretty pointless. $\endgroup$ – ArtisticPhoenix Mar 4 '18 at 11:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.