The epic series of sci-fi books by Frank Herbert “Dune”, which has now turned into a film of the same name, takes place in the distant future on the desert planet Arrakis. Herbert outlined a richly detailed world that at first glance seems so real that we can imagine ourselves in it.
However, if such a world existed, what would it actually look like?
We are scientists with specialized knowledge of climate modeling, so we modeled the climate of Arrakis to find out. We wanted to know if the physics and environment of such a world would match a real climate model.
Here is a visualization of our climate model for Arrakis:
You can zoom in on individual objects and highlight things like temperature or wind speed on our Climate Archive website.
When we finished, we were very pleased to find that Herbert presented an environment that was largely as expected. Sometimes we may need to suspend distrust, but much of Arrakis itself will indeed be inhabited, albeit inhospitable.
How to build a fantasy world like Arrakis?
We started with a climate model commonly used to predict weather and climate here on Earth.
To use such models, you must decide on the laws of physics (well known in the case of planet Earth) and then enter data on everything from the shape of the mountains to the strength of the sun or the composition of the atmosphere. The model can then simulate the climate and roughly tell you what the weather might be like.
We decided to keep the same fundamental physical laws that govern weather and climate here on Earth. If our model represents something completely bizarre and exotic, it could mean that different laws apply to Arrakis, or Frank Herbert’s fantastic vision of Arrakis was just a fantasy.
We then had to tell the climate model some things about Arrakis based on the detailed information contained in and accompanying the major novels. Dunes encyclopedia…
These included the topography of the planet and its orbit, which was essentially circular, akin to today’s Earth. The shape of the orbit can really affect the climate: look at the long and irregular winters in Game of Thrones…
Finally, we told the models what the atmosphere is made of. For the most part, it is very similar to what is on Earth today, albeit with less carbon dioxide (350 ppm compared to our 417 ppm).
The biggest difference is the ozone concentration. On Earth, there is very little ozone in the lower atmosphere, only about 0.000001 percent. On Arrakis it is 0.5 percent. Ozone is important because it is about 65 times more efficient in heating the atmosphere than CO.2 over a 20-year period.
Having entered all the necessary data, we sat down and waited. Such complex models take time to work, in this case more than three weeks. We needed a huge supercomputer to be able to do the hundreds of thousands of calculations needed to simulate Arrakis. However, what we found was worth the wait.
The climate of Arrakis is mostly believable
The books and film depict a planet with an unforgiving sun and desert deserts of sand and stones. However, as you get closer to the polar regions of the cities of Arrakeen and Carthage, the climate in the book begins to change into something that might be considered more hospitable.
However, our model tells a different story. In our Arrakis model, the warmest months in the tropics reach around 45 ° C, while in the coldest months they do not drop below 15 ° C. Like Earth.
The most extreme temperatures are indeed observed in mid-latitudes and polar regions. In summer it gets hot up to 70 ° C on the sand (also suggested in the book). Winters are just as extreme: down to -40 ° C at mid-latitudes and up to -75 ° C at the poles.
This is counterintuitive as the equatorial region receives more energy from the sun. However, in the model, the polar regions of Arrakis have significantly more atmospheric moisture and high cloud cover, which contributes to warming the climate, since water vapor is a greenhouse gas.
The book says there is no rain on Arrakis. However, our model assumes that there will be very little rainfall, limited only to higher latitudes in summer and autumn, and only in the mountains and plateaus. In the tropics, as well as in the polar latitudes, there will be clouds that change from season to season.
The book also mentions that polar ice caps have existed, at least in the northern hemisphere, and have been around for a long time. But this is where the books are perhaps most different from our model, which assumes that summer temperatures will melt any polar ice, and there will be no snowfalls in winter to replace the ice caps.
Hot but livable
Can humans survive on such a desolate planet? First, we have to make the assumption that people like the people in the book and the movie have the same heat resistance as people today.
If so, then, unlike the book and the film, it seems that the tropics will be the most habitable area. Because there is so little humidity there, wet bulb survival – a measure of “habitability” that combines temperature and humidity – is never exceeded.
The middle latitudes, where most people live on Arrakis, are actually the most dangerous in terms of heat. In the lowlands, average monthly temperatures often exceed 50-60 ° C, and maximum daytime temperatures are even higher. Such temperatures are deadly to humans.
We do know that all humanoid life on Arrakis outside of habitable areas must wear “stillsuits” designed to keep the wearer cool and restore body moisture from perspiration, urination, and breathing to provide drinking water.
This is important because the book says that there is no rain on Arrakis, no standing open bodies of water, and little atmospheric moisture that can be recovered.
The planet is also very cold outside the tropics, with winter temperatures that would also be uninhabitable without technology. Cities like Arrakeen and Carthage will suffer from both heat and cold, like a more extreme version of parts of Siberia on Earth, which can be both unpleasantly hot summers and severely cold winters.
It is important to remember that Herbert wrote the first Dunes novel back in 1965. It was two years before the recent Nobel laureate Shukuro Manabe published his groundbreaking first climate model, and Herbert lacked the advantages of modern supercomputers, or indeed any computer.
With that in mind, the world he created looks remarkably stable six decades later.
The authors modified a widely used climate model for exoplanet research and applied it to the planet at Dune. The work was carried out in free time and is intended as a suitable information material to demonstrate how climatological scientists use mathematical models to better understand our world and exoplanets. It will be used in future scientific publications on desert worlds and exoplanets.
Alex Farnsworth, Senior Fellow, Meteorology, University of Bristol; Michael Farnsworth, Lead Research Center for Electrical Machines of the Future, University of Sheffield; and Sebastian Steinig, Research Assistant for Paleoclimate Modeling, University of Bristol.
This article is reprinted from The Conversation under a Creative Commons license. Read the original article.