Scientists Simulate the Climate of Arrakis. It Turns Out Dune is a Pretty Realistic Exoplanet
By Evan Gough
Science fiction author Frank Herbert is renowned for the richly-detailed worlds he created. None of his work is more well-known than “Dune,” which took him six years to complete. Like his other work, Dune is full of detail, including the description of planet Dune, or as the Fremen call it, Arrakis.
Dune is an unforgiving desert world that suffers powerful dust storms and has no rainfall. Scientists who specialize in modelling climates set out to see how realistic Dune is compared to exoplanets. Their conclusion?
Frank Herbert did a great job, considering he created Dune in the 1960s.
In the world of Dune, the planet Arrakis is critically important. It’s the only known source of the resource called spice melange, a psychoactive drug which when used by the space navigators guild allows them to travel between stars. It’s also used by the mentats, intellectual specialists who perform sophisticated calculations. (There are no computers due to a backlash against thinking machines. Mentats take their place.) Dune’s harsh conditions make the spice difficult to harvest. However, it must be produced otherwise the whole interstellar empire would fall.
Dune is a desert world, where it never rains according to Herbert. The climate is so brutally hot that anyone who ventures out into the Sun must wear a stillsuit—which cools the body and recycles the body’s moisture—or face death.
The trio of scientists wanted to examine the fictional Dune to see how realistic it was. To do that, they relied on current climate models. Rather than publish a paper, they presented their results in an article at The Conversation.
“We needed a huge supercomputer to be able to crunch the hundreds of thousands of calculations required to simulate Arrakis.”
From “Dune: we simulated the desert planet of Arrakis to see if humans could survive there.”
A planet can be both habitable and inhospitable, much like extreme environments here on Earth. The Inuit in Canada’s far north adapted to their extreme environment, and so have peoples like the Bedouin in the deserts in Africa. So the idea of a people like the Fremen adapted to an extreme environment like Arrakis is no stretch. But how realistic is Arakis itself?
To answer that question, the authors began with a climate model used here on Earth. Models rely on physical laws at their base. The team used the physical laws here on Earth as their basis, otherwise, it suggests that Dune is a complete fantasy world. With the physical laws understood, the team then consulted the detailed descriptions of Arrakis in Herbert’s six novels and in the Dune Encyclopedia.
Then they input data like the planet’s topography and height of mountains, and the amount of sunlight reaching the surface. They also input Arrakis’ orbit, which is nearly circular much like Earth’s. The authors make special mention of the orbit, which can severely influence climate. “The shape of an orbit can really impact the climate: see the long and irregular winters in Game of Thrones,” they write.
With that data in place, the authors turned to the atmosphere and what it’s made up of. Dune’s atmosphere is similar to Earth’s, except for CO2. It’s at 350 ppm rather than Earth’s, which is currently around 413 ppm. That kind of makes sense, since it was written in the 1960s when CO2 concentrations were lower in our atmosphere.
The ozone is different, too. Earth’s ozone is in the upper atmosphere with very little in the lower atmosphere. Overall, Earth’s atmosphere is only about 0.000001% ozone, while Arrakis’ atmosphere is about 0.5%. This makes sense since ozone is more effective at warming the atmosphere than carbon dioxide is.
With the climate model populated, the team waited for a powerful computer to run it. “Complex models like this take time to run, in this case, more than three weeks. We needed a huge supercomputer to be able to crunch the hundreds of thousands of calculations required to simulate Arrakis.”
As part of their results, the trio of researchers produced a visual climate model of Arrakis.
The results? The team says Arrakis is pretty realistic and habitable, for the most part. “We might need to occasionally suspend disbelief, but much of Arrakis itself would indeed be habitable, albeit inhospitable,” they write.
There are some notable differences between Herbert’s Dune and the modelled Dune, particularly when it comes to cities. The cities of Arrakeen and Carthag are nearer the polar regions, and conditions there should be more hospitable according to the books. But not according to the model.
The model produced highs of about 45 Celsius in the tropics, which is hot but not a deal-breaker. In the coldest months, the tropics didn’t drop below 15 C. Both those conditions are similar to Earth.
The modelled Arrakis produced its most extreme conditions in the mid-latitudes and polar regions. Summer temperatures there reached a bone-scorching 70C in the model, with winter temperatures dropping to -70C in the polar regions and -40C in the mid-latitudes. The lowest temperature recorded on Earth was 89.2C in 1983 at Vostok, Antarctica. Earth’s highest recorded temperature is 56.7C, which was recorded in 1913 at Death Valley in California.
Higher temperatures in the polar regions rather than equatorial regions are counter-intuitive to our experience on Earth. “However, in the model, the polar regions of Arrakis have significantly more atmospheric moisture and high cloud cover which acts to warm the climate since water vapour is a greenhouse gas,” the authors explain.
Herbert created a planet with no rain, but the model didn’t reproduce that. Instead, high-altitude regions in the upper latitudes did receive seasonal rain. But not very much.
Herbert’s Dune also has polar caps, but the model was unable to reproduce those. That difference is the largest one according to the authors. “But this is where the books perhaps differ the most from our model, which suggests summer temperatures would melt any polar ice, and there would be no snowfall to replenish the ice caps in winter,” they write.
So, is the fictional Arrakis actually habitable? Yes, but not in the way the fictional inhabitants live there. Arrakis is a brutal world to survive on, but it’s possible.
In their discussion of habitability, the authors assumed that the fictional humans on Dune and we non-fictional humans on Earth have the same heat tolerance. In that case, the tropics are the most habitable, rather than the polar regions. Humidity is a difference-maker in this case. High humidity makes it harder for humans to shed heat by the evaporation of sweat. “As there is so little humidity there, survivable wet-bulb temperatures – a measure of “habitability” that combines temperature and humidity – are never exceeded,” they explain.
In the books, most people live in the mid-latitudes. But the models say that’s not realistic. The mid-latitudes have monthly-average temperatures that often exceed 50 – 60C in the lowlands, with daily maximums reaching higher than that. Humans can’t withstand that.
Herbert’s Dune has no rainfall and no bodies of water, so something like a stillsuit, which recycles moisture and cools the body, is necessary. Are stillsuits realistic? They seem to combine part science and part magic, but we’ll have to wait for another educated analysis of their realism. In any case, much of Dune is both too hot and too cold for humans to live without technological protection from the extremes.
This work is a good bit of fun, and the authors make it clear that they did this on their own time. They say that for his time, Frank Herbert did a good job of making a reasonably believable planet, without the benefit of the climate science and computers and exoplanets that we have today.
Their final paragraph: “It’s important to remember that Herbert wrote the first Dune novel way back in 1965. This was two years before recent Nobel-winner Syukuro Manabe published his seminal first climate model, and Herbert did not have the advantage of modern supercomputers, or indeed any computer. Given that, the world he created looks remarkably consistent six decades on.”
The three scientists behind this effort are Alex Farnsworth, Michael Farnsworth, and Sebastian Steinig.
More:
- The Conversation: Dune: we simulated the desert planet of Arrakis to see if humans could survive there
- GeekWire: How the ‘Dune’ science-fiction saga parallels the real science of Oregon’s dunes
- Universe Today: An Exoplanet So Hot There Are 7 Different Kinds of Gaseous Metals in its Atmosphere
The post Scientists Simulate the Climate of Arrakis. It Turns Out Dune is a Pretty Realistic Exoplanet appeared first on Universe Today.
November 2, 2021 at 03:29AM
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