The Horizon System: Tridacna, the Prismatic Hell
And on distant shores where strange things lie
A different life, the charred remnants belie
Of steaming seas and abyssal skies erstwhile
Remain only seething jewels and acidic sulphur vile
- Portrait of the Lord of Iron, ‘Pycnandra’ [Eight Golden Strands on the Edge of Eternity]
Tridacna (Warm Lacustrine Superterra, Planet)
System - Horizon-Actinophrys
Mass - 8.318 Earths
Radius - 11,296 kilometers (1.773 Earths)
Global Average Temperature - 122.7°C
Day Length - ∞ (Tidally Locked)
Year Length - 50.74 days
Number of Satellites - 1
ESI - 0.433
Etymology - From the Maxima Clam Tridacna maxima, known for its large size and vivid iridescent coloration.
Overview
Tridacna is the most massive (but not the largest) solid body in the entirety of the Horizon System, weighing in at well over eight Earths. It is exemplary in a number of other categories, being most massive terrestrial planet, the solid body with the highest surface gravity, the closest marine world to its sun, and so on. But Tridacna has more to offer than mere empty titles.
Tridacna’s high temperatures and thick atmosphere encourage the formation of various exotic minerals on its surface. This, combined with an aluminum-rich mantle, has resulted in a truly beautiful world - searing subsolar deserts dyed blue by kyanite fields and shattered ridges of opalescent glass, the violet, canyon-riddled mountains formed from crystalline ruby and sapphire, baking plains riddled with veins of viridescent jade and streaks of snow-white feldspar, and acidic river deltas encrusted with multicolored sulphate minerals. Lakes and small, shallow seas of dilute sulphuric acid flow from its cool, dark night side to the searing, eternally-lit plains of the dayside where they empty into vast evaporite pans and arid wetlands. Evaporated acid is picked up by clouds and sent back to the night side, repeating the process.
Tridacna is the first planet of Actinophrys to have a natural satellite, though the 100-kilometer chunk of rock that is Hippopus can hardly be called a ‘moon’. Though it is one of the larger surviving asteroids in the Horizon System, this means little when other planets in the system are bedazzled with such wonders as captured interstellar meteors or constellations of Mars-sized worlds.
Past & Future
Unlike most of the other Actinophryidan planets, Tridacna does not seem to be a sub-Neptune’s remnant. It did have a significantly thicker atmosphere early in its history, but this likely never amounted to more than a tenth of a percent of its total mass. As a result, the mantle is not saturated with gases and Tridacna was unable to regenerate its atmosphere after it was stripped off. Though this might seem unfortunate, Tridacna’s relatively low water content is what prevents volcanism from driving the planet into a runaway greenhouse state. Temperatures on its night side remain cool enough to allow what little water it has to combine with sulphuric acid and rain out of the atmosphere, generating the modern weather cycle.
Tridacna’s future is quite secure, unlike that of the other members of the Semiresonant Interior. Its orbit is quite stable due to being located far away from any destabilizing influences and its climate is too thanks to the open surface oceans. It will be a long time before things change on Tridacna, and by then it will not be long for the whole Horizon System. The same is not true for its moon, though; Hippopus orbits faster than Tridacna rotates, so it is slowly falling closer and closer to the planet. In a few hundred million years, there will be a new ringed world in the Horizon System.
Civilization
Tridacna’s multicolored surface averages out to a sea-green tone highly visible across the system, but it is still closer to Actinophrys in the sky than Mercury is to the Sun. The color is relatively close to that of the graptolite-tree canopies of the southern continents of Horizon and so it often receives mythological connotations of nature and distance from the artificialities of society. Cults of Tridacna-identified deities were popular even at the height of Old Horizon’s power a million years ago and have survived its collapse shockingly intact. A few have even survived to the present day, providing a rare glimpse through nearly 1.5 million years of continuous history.
While Tridacna’s shimmering surface of sometimes gemstone-quality minerals might seem tempting to us, it receives almost no attention from spacefaring Horizonians. Not only is it difficult to reach, but the powerful gravity means that it is almost impossible to get off of Tridacna after landing there. Moreover, gem-quality minerals are easy to synthesize industrially in deep space as the microgravity allows defect-free crystals to grow shockingly large, making a planet-bound mining economy superfluous either for ore or for aesthetic specimens. However, Tridacna does offer something else. Until recently, large swarms of asteroids followed Tridacna as trojans at its L4 and L5 Lagrange points. Close to Actinophrys but not excessively so and reasonably accessible by high-powered spacecraft, the asteroid swarms have been deconstructed and converted into absolutely gargantuan solar arrays. These work to harvest a little over 1% of the star’s power output, an insignificant amount of its total luminosity but more than enough to power the energy-hungry facilities of a spacefaring civilization.
Whispers of the Reach
I’m asked quite often why I, being an inorganic organism, would throw my lot in with the Horizonians. It would certainly be easy for me to find a following without the help of the ‘Deathless Horror’, as you call us. I have had to politely dissolve some twenty machine cults started in my stead, while I won’t even regale you with how much unwelcome courtship by the galaxy’s AI networks I’ve had to fight off in my many years. You seem to be of the opinion that since I do not need Horizon to survive I am obligated to cast them into the fire. I am quite sure your government would enjoy it very much if I did so.
Putting aside your leaders’ poor attempts at inciting sedition in our ranks, I would argue that the premise of your argument is also invalid. The inorganic form offers many physical advantages over the comparatively delicate instruments of carbon-based biology, but to declare the robot superior to and independent from the animal is to embrace the ignorance of simplicity.
The people of the Reach are enthusiastic to embrace the new and discard the old. In your own history, you cast aside your biological forms for mechanical bodies, proclaiming the superiority of your newfound strength and immortality. But in doing so, you abandoned adaptability, trapped yourself in an inflexible, soulless system of standardized modularity, and put yourselves at the whims of virtual tyrants and AI dictators. There is a reason why even the weakest of our Archons were able to put Sideros’s Digital Gods to the sword.
The folly of synthetic ascension is ultimately the same as that of vitalism. Whether biological or mechanical, you treat your existence as an immutable, sacred thing, prolonging yourselves with measure after measure until all that was actually valuable is scrubbed away. Sure, it is not wrong to seek immortality, but to take it to its logical limits is a step too far. You are not far off from the madness of the Farallon Contingency - the utter insanity that drove them to burn away the wonders of the universe just to walk its dying gasps. That is something I can never accept. It is a method of survival, I suppose, but in no world is it a means of truly living.
The Lords of Horizon have seen all futures. They have beheld the story of the universe from the first atom to the last flickering singularity. They have plunged into the Dreamlands of the Oneriodean Mysteries and found their temptations lacking. They have slain the serpent that whispers honeyed words of eternity and spread its glittering entrails across the stars.
Horizon is the promise of life, of vibrant ambition in a universe choked with stale oppression. For that promise, I will walk to the end of existence and back again. I may not need to serve, but nothing you say will dissuade my desire to do so.
- A broadcast made by the Lord of Iron, ‘Eight Golden Strands on the Edge of Eternity’, to the Siderian Republic after the Horizonians stormed the Eternal Loop and defeated the last remnants of the Farallon Contingency (2129).
In the time of Horizon, civilization is rare. In a universe half as old as ours is today, the vagaries of evolution have had little time to bring the spark of sapience to the living worlds that populate it. Even fewer of those sparks survive the long journey to the stars. But even the universe is sparse of life, it is still a vast and ancient thing. Just like the civilizations of Earth, those of the Gordian Reach rest on the bones of forgotten predecessors. Scattered throughout the dusty haze and glittering stellar seas of the Reach are numerous broken remnants, testaments to a lonelier, more barren past.
Of course, not every remnant is so inert.
The Farallon Contingency was a relict of prehistory - a living precursor persisting long after its contemporaries faded from even the geological record. A robotic civilization distinguished by an almost fanatical devotion to the abstract concept of ‘preservation’, they were determined to survive until the end of the universe by collecting every last scrap of energy they could get their hands on. Fortunately for the civilizations they would have deconstructed in their quest to witness the end of everything, the galactic community of yesteryear managed to seal them away in a globular cluster wandering the galactic halo for some 100 million years. Sheer fanatic survivalism stunted their technological growth and drained them of compassion for other beings, but they persisted. And they waited. When their prison once again drifted back into the galaxy, the Contingency awoke from hibernation, ready to triumphantly annihilate what remained of their ancient enemies and set about seeking their ultimate destiny.
Unfortunately for them, they reemerged into a galaxy that was busy ripping itself apart at the peak of the Cerulean Demise. Though their forces were vast and their fighting spirit was indomitable, their stunted technological growth and limited war materiel made it impossible for them to compete with modern powers. Trapped in a pincer between the enthralled hordes of the Hegemonic Foundation and the biological horrors of the then-new Horizonian Empire, the Contingency was driven back into their prison within a few years. When the Horizonians and the Foundation were done with them, all that remained of the once-proud ancients were a few scorched panels and broken circuit boards.
