Assessment of the planet Arrakis (Canopus III; “Dune”) in 10,191 AG

The planet Arrakis is the source of the most important resource in the entire galaxy: the spice melange. The spice extends life and expands consciousness, permitting the folding of space by Guild Navigators and grating prescient powers to the Sisterhood of the Bene Gesserit. The spice binds the Imperium together. This makes Arrakis (colloquially “Dune”) the most vital and strategically important planet in the Imperium.

Arrakis Latitude

A map of the northern polar region of Arrakis. Please click for a larger version.

Arrakis is the third planet of the star Canopus, located 313.74 ly from the Imperial Capital on Kaitain (310 ly from Old Earth). Canopus is an ancient star, a white giant, having already completed its hydrogen burning phase. It is possible to likely that Canopus once had more than the planets currently visible, but the rest were swallowed up by the star’s previous expansion phases and effectively destroyed. Arrakis may have been a satellite of a larger body before being catapulted into its current orbit by the same expansion event.

Arrakis is an unusually small planet, matching almost exactly in size the dimensions of Old Earth’s moon, Luna (diameter: 3,474.2 km, circumference: 10,921 km). The planet’s density is considerable, however, meaning that its mass is greater than is normal for a body of its size, giving it a gravitational field only slightly weaker than Galactic Standard at 0.9g.



Arrakis is mostly covered in desert terrain similar to the Sahara of Old Earth. The open, flat desert, known as the Great Flat, runs from approx. 60°N to 70°S and consists almost entirely of sand dunes, with very rare rock outcroppings. The sand dunes are about 100m thick, sitting on the bedrock beneath (known as the Great Bled, which forms “sea level” on Arrakis). The Great Flat is scoured by the massive coriolis storms which rage across the open desert. These storms can engulf huge parts of the planet for days or weeks at a time, making any suborbital travel impossible.

The planet’s polar regions are considered habitable. A vast rock formation (varying from 4,500m to 4,600m in height, apart from the Rimwall region which rises to 6,240m) known as the “Shield Wall” wraps itself around the northern polar region. The rock itself and the basins in its surface are densely populated with towns and villages, including the only two cities on Arrakis: Carthag (seat of the Harkonnen government for the past eighty years) and Arrakeen (the more traditional, long-term seat of planetary government).

The highest point on Arrakis is Observatory Mount, located in the Broken Land of the Shield Wall. Observatory Mount is 8,110m (26,607.61 feet tall). The Prime Meridian of Arrakis (0° longitude) passes through Observatory Mount, as per ancient tradition. The lowest region is the northern polar sink, which drops to 500m below the Bled level.

Other regions of interest include the rock formations known as the False Walls, which are located close to the Shield Wall and have been known to confuse travellers; the Sihaya and Habbanaya ridges, the Cielago Depression (200m below Bled level), and the Minor Erg, a small region of open desert locked between the Shield Wall and eastern and southern False Walls. Also of note are the Hagga and Imperial basins, the most heavily-populated parts of the planet.

The southern polar region is less well-charted than the northern. There are few corresponding rock regions which are open to habitation. Some believe smugglers may use what rock formations there are in the south to land goods away from imperial sensors before sneaking them in under the orbital trackers.



The sand temperature on Arrakis is 345° to 350°K (72-77°C), dropping by 25° above the sand ground level and by 55° underground. Shade reduces the temperature by approximately 18°. Survival on the surface of Arrakis is borderline impossible on the open desert without the use of a stillsuit, a special survival mechanism which reduces body temperature to survivable levels and includes a near-perfect water recycling system.

Finding food in the open desert is highly improbable, but there is some extremely isolated tuber growth in cooler crevasses and canyons outside of the direct sunlight. There are also some native lifeforms, such as the kangaroo mouse, desert bat and other animals which are edible if they can be hunted, which is not an easy task.

Even for a human well-supplied with food and a well-maintained stillsuit, travelling between the 60°N and 70°S line is ill-advised for the violence of the coriolis storms, vast storm systems which build up across thousands of kilometres of open desert and can cover entire hemispheres for weeks at a time. The Shield Wall and other features of the northern desert help break up the storms in inhabited regions, but on the open desert they are lethal, with winds so fast throwing up sand particles to such velocity they can shed skin from bone.



The most famous feature of Arrakis, apart from the spice, is the native lifeform known as the sandworms, also Shai-hulud or “Maker”. Sandworms are immense worm-like creatures with no eyes but keen movement-sensing organs. They travel under the sand, between the surface and the Great Bled, but can be drawn to the surface by rhythmic movements, such as footsteps, explosions, mining equipment or the use of special devices such as “thumpers”. The Holtzmann field generated by shields sends them into a special frenzy, and they will attack any site protected by a Holtzmann field immediately.

Sandworms are immense in size; the specimens observed in the northern mining fields range from 50m to 200m in length, but even larger monsters exceeding 400m in length have been seen in the deep desert. Destroying or even injuring a sandworm is regarded as impossible with anything less than field atomics, so instead people are directed to avoid them at all costs.

Arrakis Planet

Arrakis as seen from space, art by Christopher Doll.


The long-term history of Arrakis is unclear; Canopus is an ancient star which has already undergone its yellow dwarf and red giant stages and is now burning helium in a white giant phase, as well as being an active source of x-rays. It is currently radiating at 10,000 standard solar luminii and is expected to dissipate over the next several tens of millions of years into a planetary nebula, leaving behind a smaller white dwarf (Canopus has insufficient mass to ever go supernova). At present, Canopus is the brightest star in the core of Imperial space.

Because of the challenging nature of the Canopus system, Arrakis is extremely fortunate to remain habitable. Theories have ranged from Arrakis being a satellite ejected from further in towards the star before its expansion stages, to it being captured from the so-called “Canopus B”, a star estimated to have made a close pass of the Canopus system several tens of millions of years ago and may now be gravitationally trapped by the core star at a distance of 6.2 light-years. Either way, the planet is fortunate to have found itself in Canopus’s new “life zone” and flourished…relatively. It is known that Arrakis was once much wetter than it is now, with samples taken from the Great Bled (underneath the sand) suggesting that Arrakis’ surface temperature was, for a very long time, in the absolute range of 254-332°K (-19° to 59°C) with a growing season of around 284-302°K (11-29°C), and the desertification of Arrakis is a relatively recent phenomenon, perhaps only on the order of twenty to fifty thousand years. The reasons for the desertification remain unclear, although some ecologists have tied the phenomenon to the presence of the sandworms.

It is also unknown when Arrakis was discovered. Eleven thousand years – one hundred and ten centuries – passed between the first fumbling attempts towards the stars by humanity and the chaotic insanity of the Great Revolt (the Butlerian Jihad), the inter-religious war raged between disparate branches of humanity over the use of AI, “thinking machines”. At the end of the war, which lasted ninety-three years, the machine-worshipping cults of humanity had been purged and the old religions of faith and spiritualism (in some cases allied with the always-resilient forces of secularism) had prevailed. These forces came together in the Commission of Ecumenical Translators to create the Orange Catholic Bible, which became the new religious textbook for the spiritual enlightenment of humankind. The work permeated through the 13,333 worlds of the Landsraad League, the body which for two thousand years had united the disparate worlds of humanity in a very loose confederation of trade and diplomacy. Several decades later, the Spacing Guild was founded as we know it, bridging the worlds by folding space, allowing ships to travel from one world to another instantly rather than taking the weeks or months required by standard FTL drive. This was done through the use of the spice melange, which is native only to Arrakis.

Thus the discovery of melange must predate the founding of the Guild, 10,191 years ago. As the brightest star in that original cluster of worlds within 500 light-years of Old Earth, Canopus must have been a target for interstellar exploration, but perhaps a low-priority one, for its hostile environment would have made it a poor candidate to harbour inhabitable worlds. Nevertheless, Arrakis was discovered and explored early enough for the melange to be discovered and then exploited by the nascent pre-Guild organisation in the century or so leading up to their official founding.

The initial exploration and settling of Arrakis was likely done by hardy explorers and hardy miners, working the wastes to find enough of the spice to satisfy the needs of the Guild Navigators. The Navigators are known to have discovered the ability of the spice to fold space and extend prescience, but how far they let this knowledge develop is unclear; the Bene Gesserit instead used various elixirs and poisons to achieve much the same effects until the more potent properties of melange were discovered; it is also known that the ability of the spice to retard the ageing process in normal humans was not discovered until the reign of Shakkad Corrino, “the Wise”, through the research of the Imperial Chemist, Yanshup Ashkoko. Both of these events may have been some time after the formation of the Guild. As such, the importance of the spice on Arrakis may have been relatively unknown for several millennia.

What is known is that the large-scale settlement of Arrakis did not begin until the Zensunni settled there. Religious exiles and wanderers from Old Earth, the Zensunni were forced to make six migrations to other worlds. Their first stop was Poritrin, followed by Salusa Secundus (where tradition holds that they were slaves for nine generations), Bela Tegeuse, Rossak, Thurgrod and Harmonthep, in the Delta Pavonis system. The destruction of Harmonthep (by means unknown, save it had no effect on neighbouring Caladan, already then the primary Atreides stronghold) saw the Zensunni flee en masse to Arrakis. Here, on a small, dry and arid world with a valuable resource but little appetite among the Great Houses for its conquest, they found a ready home. Some of their descendants went into the basins and founded villages and towns, becoming the ancestors of the pyons class, but others went into the deep deserts, to the remote ridges and rock formations and there founded secret strongholds, sietches, and from there they took a new name, the Free Men of Arrakis, or Fremen. Over millennia, the Fremen have become legends, their numbers and strongholds unknown.

In 10,111 the rule of Arrakis was given as a fief to House Harkonnen by the Emperor. House Harkonnen’s rule of Arrakis was efficient but brutal, seeing the planet’s workforce worked almost to death in the production of spice. Due to the political manoeuvrings of the Landsraad, the Harkonnens have been stripped of their claim to Arrakis. Instead, their fiercest enemies, the Atreides of Caladan, have been given ownership of the planet on a new contract to mine spice more efficiently.


Notes on the map

The size of Arrakis is not given in any of the six canonical Dune novels written by Frank Herbert. The Dune Encyclopedia suggests that Arrakis is slightly smaller than Earth, but no evidence is presented to support this and Frank Herbert himself regarded The Dune Encyclopedia as a fun book but effectively non-canon. In lieu of other data, Dune fans in the 1990s seemed to settle on the idea of Arrakis being about the size of Mars, perhaps based on the superficial visual similarity of the two planets.

However, it is possible to work out the size of Arrakis from information provided in the original Dune novel by itself. This is because we are given one key distance in the book – the distance between the cities of Carthag and Arrakeen, which is fixed at 200 kilometres – and the provided map gives us longitude and latitude information, most importantly establishing the 60°N line on Arrakis. Using the established scale, we can measure the diameter of the 60°N line (through the north pole) at 1,800 km.

We can compare this diameter to the similar dimensions of the same latitude line on Earth, Mars and the Moon, which give us respective figures of 6,693 km, 3,551 km and 1,820 km respectively. Thus we can establish that Arrakis is the same size – perhaps even a tad smaller – than Earth’s moon.

Although helpful from some perspectives, such as the speed with which large land armies such as those of the Fremen seem to zip around on Arrakis, this does seem a tad implausible, as small, low-mass planets will have considerably weaker gravity than on Earth and this makes it less likely that the planet will have retained its atmosphere. However, it is possible that Arrakis is rich in dense metals, which in turn have made the planet considerably heavier than is normal for its size and given it a gravitational field of 0.9G, as noted in the novel.

The small size of Arrakis is supported by a discussion between Thufir Hawat and Paul Atreides early in the novel, when Thufir says the coriolis storms build up over “six or seven thousand kilometres” of the equatorial circumference band, which is actually smaller than our Moon (where the equatorial circumference extends for just over 10,000 km) but vastly smaller than Mars (20,000 km) or Earth (40,000 km).


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