# Can a desert planet sustain human life? [closed]

Can a desert planet sustain human life? My character is a human being who lives on a desert planet, is this possible? (The planet has an earth-like atmosphere)

• "California/Mexico" desert or "Sahara" desert? Humans native, or interstellar migrants? – RonJohn May 16 '17 at 3:58
• California and interstellar migrants, sorry for not clarifying. – pin-up enthusiast May 16 '17 at 4:01
• Also, as much as sci-fi pretends otherwise, planets are b-i-g big. Desert planets are going to be pretty dead. – RonJohn May 16 '17 at 4:01
• How poor can the humans be? What's their purpose on the planet? – RonJohn May 16 '17 at 4:02
• How poor? as in financially or health wise? – pin-up enthusiast May 16 '17 at 4:04

The Premise

While I realize that this is not part of the question, single biosphere planets are very rare. Especially with an earth like atmosphere the poles are quite likely to be a much cooler place, assuming the planet also orbits in a habitable range in it's solar system. As such consider diversity, and possibly only have your character's home continent be a desert. Your readers will find it much more realistic and it will not remind them as much as a long time ago in a galaxy far far away...

While it is not impossible it is highly unfavorable. What would likely be required for a desert planet is naturally occurring tunnel systems that collect water both at the top, so plants can get both sun and water without the water evaporating, and lower down in the tunnels so that the humans would not die of heat exhaustion or skin cancer.

• While its true that a planet will presumably be cooler at the poles than at the equator, I don't see how you can say that desert planets are rare. We know of four "rocky" planets: Mercury, Venus, Earth, and Mars. Of these, three are desert planets and one is not. From the observed evidence, desert planets are the most common type. :-) – Jay May 16 '17 at 15:06
• @Jay Single biosphere planets that are in the habitable zone are quite rare. There is no reason to talk about all the desert planets that are inhospitable. – William C. May 16 '17 at 16:26
• Ok, limiting to goldilocks zone planets, still, we have adequate data to discuss the question on only one such planet: Earth. Based on scientific evidence, actual experiments and observation, there is nowhere near enough information to say whether such planets are rare or common. You can speculate based on theories about climate et al, but there's very little evidence to really go on. You're trying to extrapolate one from one data point. – Jay May 16 '17 at 16:37

How much of a desert is it? If it's completely waterless, then no, not without constantly bringing in water from somewhere else. If it has a little water, then there would probably be large stretches that would be uninhabitable, but others that would be livable with careful conservation. People have lived in the world's great deserts like the Gobi and the Sahara for a very long time. Not many people, and they have to be insanely careful (by everyone else's standards) with what little water they have, but they manage.

Please define what a desert planet is btw.

If it has an earth-like atmosphere, it isn't a desert planet. A desert planet with a breathable atmosphere and tolerable temperatures and water is something that doesn't make a whole lot of sense, even though it is very prominent in fiction. However, it all depends a bit. A human can live on Mars - see the rather bad movie "The Martian". I did not read the book. Mars I guess would qualify as a desert planet - but he would have to bring almost everything he needs to survive with him. Let's get into detail:

Water: Water is relatively common and can be found almost anywhere in the universe. I guess with very high-tech technology, it can be harvested. But it should be much easier to bring and recycle it.

Oxygen: Has to be introduced. If there is life as we know it, it no longer can be a desert planet. The easiest way to do it is to wear a space suit all the time and live within buildings. You will not find another planet with the same oxygen concentration as earth that is mostly dust, even if some kind of life exists in some kind of small ocean.

Temperatures: Will vary greatly. Check out continental climate. But it shouldn't be much of a problem on a planet like Mars because the atmosphere is so thin. You can also go the other way, a Venus like planet - but this doesn't sound like what you are asking.

Food: Well, grow it damn it.

Storms, weather and so on: All depends on how thick the atmosphere is and other parameters, you basically should have a lot of freedom here.

This isn't meant to be an exhaustive list. There, however, is another alternative:

Build a planet that is in the process of developing life, maybe with a rather small continent with no plants on it (yet, for the next couple of billion years). It could have an oxygen atmosphere, it would have a desert and nothing else on land - but be aware of weather. This might qualify more as an "ocean planet", but I think you should be flexible here. Currently, nobody would be permitted to land on such a planet since humans do not wish to contaminate and alter the path of ecosystems - you would have to discuss this a little bit maybe (why this philosophy has changed).

Here is my suggestion: Instead of making a desert planet (planets are rather large btw), make a planet with a desert

How barren is the desert? And how high-tech are the people?

People manage to live in deserts on Earth. The Sahara is probably the most desolate place on Earth, yet people live there and some even built cities there.

If there's any water at all, and any nutrients in the soil, than it should be possible to eke out some kind of living.

BTW a truly barren desert with an Earth-like atmosphere is problematic. Earth's atmosphere is sustained by complex interactions, of which the most basic is that animals generally take in oxygen and give off carbon dioxide while plants do the reverse. If a planet has no plant life, what is producing the oxygen? I suppose with sufficient imagination you could come up with some mechanism, of course.

Yes.

Note: you have something which maintains the oxygen content of the athmosphere. It can be:

• some abiological process (for example, iron oxides of the soil can catalyze the $\mathrm{CO_2}$ decay)
• even if the planet is a desert, it can have a minimal ecosystem, which can be enough to maintain the $\mathrm{O_2}$ content.

Note, we could have even bases on the Moon, which is far more harsh environment as a desert. It would cost around \$500billion, and we don't have rockets since the seventies to be able to go there. But there are existing plans and cost estimations.

It is also possible, that only the majority of the planet is a desert, and the little ecosystem is centralized to the few seas and around it.

I think there's a problem with the premise, because of the atmosphere.

Early proto-earth had lots of active volcanoes, which spewed carbon dioxide into the air. That's one big reason plants developed first: they had something to breathe.

But the plants converted all that nice carbon dioxide into oxygen, which was poisonous for them. Luckily, along came animals, who drank in all that delicious oxygen and converted it back into carbon dioxide.

So you would need to have an explanation for where all the "earth-like atmosphere" came from, as well an explanation for keeping the balance between oxygen-using / carbon-dioxide-spewing animals (like humans), and carbon-dioxide-using / oxygen-spewing plants, of which there would be very few in a desert.

(I hope I got that atmospheric science right. I haven't updated my planetary atmosphere knowledge since college!)