Chthonian type world; joint NoCoZo and Metasoft sovereignty

Sisyphosian Hills
Image from Musicphreak
Sunrise on Sisyphos: this planet is less than three million kilometers from its star (the world is tidally locked, so such sunrises occur only on the terminator and occur due to libration effects)

Sisyphos - Data Panel

System:HIP 63469
Primary:HIP 63469
Class:G5 V
Luminosity: 1.5 x Sol
Region:Low Middle Regions, Constellation Hydra; Distance from Sol 260 ly
Class :Chthonian type - a former gas giant which has lost nearly all its atmosphere by evaporation after orbiting too close to its local sun.
Diameter :25300km
Density :7017 kg/m3
Surface Gravity :2.53 gee
Escape velocity :25 km/s
Temperature :Day side 2000 Celsius
Night side 500 Celsius
Orbital period :0.96 standard days
Semimajor axis :0.02 AU

Physical Characteristics

The world of HIP 63469b, known as Sisyphos, was discovered in 2084 c.e. by interferometry satellite and identified as one of the rare class of evaporated gas giants known as Chthonian worlds.

Three billion years ago this world formed in the thick solar nebula around the young star HIP 63469; originally a gas giant 300 times the mass of the Earth, it possessed a dense core of iron, overlain by a mantle of aluminium and silicon, a thin crust of diamond, an ocean of metallic hydrogen and a massive envelope of hydrogen, helium and methane. Many other chthonian worlds are known to exist; some formed by accretion around a massive solid core, and are generally dense, very high gravity worlds like Sisyphos; others formed as disk instabilities and have smaller, lighter cores.

Due to friction with the dense solar nebula, this giant world migrated inwards, expelling several other large worlds and countless smaller bodies from the infant solar system. When HIP 63469 became active enough to expel the remnants of the nebula, Sisyphos was in a very close orbit, no more than three million kilometers from the star's hot surface and orbiting once every 0.96 standard days.

The effect of the incredible influx of solar energy on this giant was profound; the atmosphere was heated to more than 2000 Celsius, and expanded until the giant was bloated and superheated; under the pressure of the light and the solar wind the top layers of the atmosphere were stripped away into a comet-like tail which streamed out into the largely empty outer solar system.

Eventually the atmosphere was almost completely lost; the little that remains cycles around the equator in red hot winds to the dark side, and then cools and returns over the poles in a skewed rotational pattern. Because of the gravity this atmosphere thins quickly and barely reaches to the tops of the highest diamond and basalt mountain ranges. Hot clouds of silicates form in these asymmetric winds and rain molten silica or jewel-like snow onto the highlands.

Image from Steve Bowers
Sisyphos retains a relatively thin, compact atmosphere, mostly nitrogen, CO2 and SO2


When the Hydra Outreach, an exploration franchise allied with the NoCoZo reached Sisyphos in 3321 the world was confirmed as uninhabitable; despite this the Outreach hyperturings desired to tap the vast flux of energy passing through the atmosphere and body of this hot world. To best achieve this goal they invited their robotic allies from the Version Tree to assist in the construction of high temperature energy collection arrays, both on the surface of Sisyphos and in orbit around HIP 63469.

For many centuries specialised moravec robots had been used by the Metasoft Version Tree to develop and dismantle hot planets; using diamondoid, corundumoid and other materials resistant to high temperatures these hot worlds could be shaped and exploited. The commander of the Sisyphos vecs, Xor Thyratron, was a gifted and famous transapient individual.

Xor Thyratron was a distributed entity, who used several specialised crab-like robot bodies at any one time; eir specialisation in mineralogy and wide range of detection equipment led em to develop a novel aesthetic sensitivity. Thyratron ensured that all eir subordinates in the Version Tree were programmed with this new aesthetic; over time the vecs of Sisyphos became enamoured of their world and the beautiful interactions of polarised and unpolarised light in the diamond and other mineral breccia, and the jewelled rain falling from the sky.

In a communal decision the vecs determined to defer the disassembly of their beautiful planet; they were willing to supply the Hydra Outreach hyperturings with an ample power supply, more than enough to develop the thousands of smaller bodes in the outer system; but the creation of a power swarm from the mass of Sisyphos would not be an option for the foreseeable future.

Through a remarkable feat of negotiation Thyratron came to an arrangement with the disappointed NoCoZo representatives. The broad expanse of the surface of this giant planet could accommodate many refrigerated colonies, which could accommodate millions or even billions of humans adapted to the high gravity. These colonies were located on the dark side, but energy collection systems on the sunlit side were sufficient to supply the requirements of a comfortable hi-tech society and allow the export of energy and other products to the outer worlds.

The Outreach hyperturings were impressed with Thyratron's vision of a society of humans and vecs in harmony on this unusual world and agreed to this arrangement.

Image from Steve Bowers
The dark side of Sisyphos glows with excess heat

The Kobolds

A new (tweaked) clade of humanity was developed for this high gee world; a metre tall and the same broad, they became known as Kobolds to the rest of the Terragen sphere; despite their short stature, they were strong and hardy and capable of great feats of strength in Earth-like gravity regimes.

Their warrens were generally spacious enough to accommodate a two metre human from the outside worlds, but such visitors generally relied on powered exoskeletons or mobile chairs for support. With a lining of diamond sheeting and cooled to 25 Celsius the warrens were continually being extended by the benevolent white crabvecs, who educated the humans in their mineralogical aesthetic. After a thousand years of expansion and development the warrens covered a tenth of the dayside and a quarter of the night side, more than a billion Kobolds accommodated in spacious luxury.

Many Kobolds became skilled in jewellery and the play of light through crystals; their halls glittered and shone, sometimes with subtle radiance, sometimes in overwhelming brilliance. The greatest jewelmaster of them all was Wallid eh-Nah, who also successfully promoted his work and that of other Sisyphos craftsmen throughout the Known Net; he became fabulously wealthy but was seemingly never content. By 8942 he was importing hi-tech hedonic gear into the warrens, together with sport weapons and hobby equipment from the most depraved sectors of the NoCoZo.

Ellalla oh-Reh was at that time the most powerful Kobold politician and figurehead, the Regnant; she found the corruption brought by eh-Nah's excesses repugnant, and attempted to suppress them. Over a period of time the warrens erupted into chaos as the power struggle changed into warfare. In general the White crabvecs did not intervene, but when they did they seemed to enrage many humans on both sides.

Eventually one of the bodies of Thyratron emself was destroyed by the indomitable Kobolds of e-Nah's personal guard. Thyratron was forced to act, and expelled eh-Nah and his jeweller warriors from the world of Sisyphos; as the crabvecs maintained their artificial environment the rebels had no choice but to depart. The loyalists and the Regnant were allowed to remain, but many of her faction also migrated off-world over the next few centuries.
Today the warrens are once again becoming a lively and interesting place to live or visit; but many of the crystal tunnels are still deserted - mysterious places to explore for those who can withstand the crushing gravity.

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Development Notes
Text by Steve Bowers
Initially published on 05 May 2004.