A cold desert planet

Question

I know that by definition, a desert implies a lack of water and, as such, makes it very hard for living things to survive there.

In the story I'm writing, the characters come across a planet that is essentially an entirely cold desert world. The reason people live here is that it contains the ruins of a long-lost culture, and so is considered a holy place by them.

My question is: What circumstances would a planet need to be in in order for it to be a cold desert world, and where and how would people most likely survive on one? (There is a breathable atmosphere.)

Answer 1

Antarctica is a cold desert, and pretty much at the limit of human habitability using mostly modern technology. The high arctic and parts of northern Siberia can also be classified as cold deserts, and certainly other places, like the Gobi desert, can also fulfil these definitions.

What you need to realize is that these are isolated areas embedded in a larger planetary system, and are cold deserts because they are at the extreme edges of their "systems". Antarctica would not be a cold desert if it was not in the middle of the polar ocean (and indeed, in the distant past and in the distant future, plate tectonics will move Antarctica to where it will be warm and wet...).

Single biome planets are the bane of SF, and usually the mark of writers who have limited skill or imagination (or who don't care). SF writer and editor Jerry Pournelle mocked this idea with the infamous line "It was raining that day on Planet Mongo..."

If Antarctica represents the effects that you want your explorers to encounter, you need to do some serious world building. Maybe the remnants of the alien culture only survive "for real" in an isolated setting like Antarctica or the Gobi desert, so your explorers can go to Thailand for vacations and R&R, but have to trudge back into the desert wilderness to study or explore the alien artifacts. Many of H.P Lovecraft's works used this idea. In that case, your planet looks a lot like Earth.

If you want the entire planet to be cold, then the Antarctic conditions might be found at the equator and the polar regains are OMG! cold and hostile, requiring the equivalent of spacesuit technology to survive. While Neolithic peoples have lived in extreme environments during the last ice age, they were not living "on" the glaciers. They need to access wood and stone to make tools, and hunt and forage for food. No primitive culture will be able to survive such a planet, and it would resemble "Snowball Earth" of 650 MY in the past (which was hostile to most life, except for extremophile bacteria and very simple single celled organisms). There will still be areas of open water, and some circulation of the hydrosphere, but you will have to work out the effects you want and how the planet is going to create these.

Finally, very alien worlds could have these conditions. Mars is a cold, dry desert now, but may still have megatonnes of water buried in permafrost and at the poles. Of course to become a cold desert, it is farther from the Sun than Earth and has lost most of its atmosphere. Once again, only an advanced technology could survive in such a setting. SF authors as varied as H.G Wells [War of the Worlds], Edgar Rice Burroughs [Barsoom] and Richard C. Hoagland [The Monuments of Mars] all have as a premise that advanced civilizations and technologies are needed to survive on the surface of Mars (Ray Bradbury and C.S.Lewis's stories should be thought of more as allegories than straight up Science Fiction).

So make some decisions and get to worldbuilding. Some sites that might help include:

http://world-building.com

http://worldbuildingschool.com

http://world-builders.org

Also read books by "Hal Clement", who was a past master of "world building" in hard SF. I especially liked "Mission of Gravity", but "Media: Harlan's World" was another very interesting world building project he collaborated on with such SF luminaries as Harlen Ellison, Larry Niven and many others.

Don't forget to provide links to your stories as well....

Answer 2

Deserts are described as areas where rainfall is lower than 250 mm per year (on Earth, in else worlds may be different number).

Thus there is minimum of flowers or they are assimilated to survive such conditions (cactuses, succulents, lichens). Also there is minimum of permanently living animals.

Cold deserts like Antarctis (well, there are some snow storms - but even if they are huge, total amount of snow is very low) is not inhabited by permanently living animals, if I am not wrong. Only some penguins stay there at time of breeding - but else they live elsewhere. And of course, they hunt fishes - and so they are not tied to Antarctis. But some sea streams may affect plenty of food.

Hot deserts like Sahara have a bit more plausible conditions, because even if days are very hots, nights offer cold and a little of water condensated to waterdrops and caught by accidental flowers. So, there you may find a various insects and lizards. And on half-deserts you may find also some mammals, living mostly at night or beneath ground.