The Horizon System: Tonicella, the Life-Giving Drought
Glass like fire, shining through the night
Life ephemeral, like the rains some day
Keep surviving, spite heavenly light
No one can stop me from finding my way!
- Portrait of the Archon of the Radiant Corridor, ‘Sawdonia‘ [Glittering Roads Over Heaven]
Tonicella (Temperate Lacustrine Terra, Planet)
System - Horizon-Actinophrys
Mass - 0.764 Earths
Radius - 5,977 kilometers (0.936 Earths)
Global Average Temperature - 46.69°C
Day Length - 4.940 days
Year Length - 318.04 days
Number of Satellites - 2
ESI - 0.883
Etymology - From the Lined Chiton Tonicella lineata, for its tenacity, toughness, and vivid colors.
Overview
Tonicella is one of a number of paradoxes in the Horizon System. Though this searing terrestrial world should have fallen to a runaway greenhouse long ago, it instead hosts small seas of liquid water and a fair amount of life. This stay of execution has occurred because of Tonicella’s extreme aridity - without great expanses of open ocean to produce planet-warming water vapor, the runaway simply cannot get enough momentum to start. Though average temperatures push 50°C, Tonicella’s torrid air is bone-dry.
The scarcity of water renders the vast majority of Tonicella’s surface a sun-bleached desert. Vast expanses of land nearly barren of any life stretch between rare oases, soaked in the red of rusted iron or the white and grey of vast salt pans. With so little water, Tonicella does not have ‘continents’ in the usual sense, but rather a single, solid piece of crust not all that different from the surfaces of Venus or Mars. Volcanism and mountain-building thus occur not as bands but as singular hotspots scattered across the planet, regions of rare activity whose clement conditions offer rare refuges from the heat and dry.
But life is nothing if not persistent, for even in a desert hell like this do an eclectic assemblage of strange beings dare to survive and thrive.
Lifeforms
Life on Tonicella is harsh, monotonous, barren, and usually short.
While the inhabitants of Cryogenia could easily weather subzero temperatures and Riftian life would shrug off being boiled alive, very few organisms can tolerate rapid swings between the two. That is exactly what happens on Tonicella, however, so anything with the misfortune of living there will have to get creative. Beyond the extremes in temperature, Tonicellan lifeforms also have to deal with such unpleasantness as critically low oxygen, critically low carbon dioxide, low atmospheric pressure, high levels of UV radiation, and extreme salinity, all at once.
Photosynthesis is difficult on Tonicella, with little carbon dioxide and far too much light. While plants on more clement worlds use the sugars they produce to build their tissues, vegetation on Tonicella can barely make enough to feed themselves. Thus, Tonicellan plants are not composed of cellulose but rather a mix of siloxane resins and quartz that resembles fiber-optic glass, which many forms also use to channel light to underground photosynthetic apparatuses. To minimize the surface area with which to lose water, forms like globes, meshes, and puffs of needles predominate - leaves are utterly unnecessary. Many are pale shades of blue or violet to reflect Actinophrys’s harsh light, while those who hide underground add opalescent white hues to the coralline forests. But the true masters of autotrophic life on Tonicella are not plants, but microbes; extremophiles similar to Earth haloarchaea swarm in desert sands even the toughest of plants would find uninhabitable.
Heterotrophs on Tonicella have an even harder time than the autotrophs, as both the siliceous flora nor the bacterial crusts are exceptionally hard to digest. The vast majority of heterotrophic life on Tonicella is microbial, existing in suspended animation and feasting on autotrophic organisms when conditions become clement much like how their Horizonian ancestors did. However, a scarce few lineages have become comparatively gigantic. Insect- and chiton-like animals as large as rabbits are not uncommon sights in the canyon forests, while flighted, dragonfly-esque forms as large as eagles soar through the desert skies in search of sparse prey and burrowing worms and starfish-like creatures lie waiting in the warm sands for unwary migrants traveling from oasis to oasis.
Past & Future
Tonicella is one of a few planets around Actinophrys which never had large supplies of water. The total volume of water inside Tonicella’s mantle is less than 40% that of Earth’s oceans, while less than 1% of an Earth ocean’s worth is accessible on the surface. It is unclear how such a dry planet could form when on both sides it is surrounded by water-rich worlds, but one hypothesis holds that Tonicella was assembled from inner-system protoplanets which rode the wake of Chrysaora out into the forming Resonant Worlds. It may have once had as much water on its surface as Earth did, but these nascent seas would have been blown away just like the thick atmospheres and erstwhile superoceans of the other Resonant Worlds.
Unlike Riftia, Tonicella has never been much more habitable than it is now. While microbes have called Tonicella home for over a billion years, most of the flora and fauna arrived just short of 300 million years ago, the same time the apocalyptic end-Caeliferan Mass Extinction nearly put an end to life on Horizon. This is conspicuously close to the time that complex life abruptly appeared on Riftia, Changxing, Dendrogramma, and Erenna, which lines up with the hypothesis that the extinction was caused by a truly apocalyptic asteroid impact that blasted life-bearing rocks throughout the Horizon System. Though only the toughest extremophiles made it to Tonicella, they have managed to eke out a fair if meagre existence across the sands of this barren world.
Civilization
Tonicella’s rusty disk appears in Horizon’s sky as a pink-red star not too different from Rhopalura and Alvinella-Chrysomallon, but it wanders twice as far from Actinophrys as the latter. Though all would be considered ‘morning stars’, the Horizonians were always well aware that it was different from them. This cultural separation of Tonicella from the inner worlds was only strengthened by the discovery of life on the planet. Modern populations on Horizon have forgotten about the physicality of the other planets, but they still recognize that Tonicella is inhabited, treating it as a kind of hell-dimension in which their sinful dead are incarcerated. Still, they remember its key characteristics, speaking of a bone-dry, nearly-airless place with undrinkable water and food hard as stone.
Tonicella was never colonized by Old Horizon because its atmosphere was entirely unbreathable to its people. Even modern Horizon, despite its cosmopolitanism, is loathe to let its bioforms spend much time on the planet’s xeric, searing surface. Even those most desert-adapted Horizonians have trouble weathering the sheer variety of environmental hazards that Tonicella presents, while the airborne sand is enough to deter even mechanical colonists. With no willing colonists nor any legitimate economic interest in going there, Tonicella remains left to nature even in the modern day. Save for a few truly mad scientists, it seems that this world was never meant to bear the weight of intelligence.
Whispers From the Reach
<PUBLIC> VOICE CHANNEL ID Z8_GND_5296 - Record of 2219-12-21, UTC 15:22:24.95
Participant IDs: <0806−661> | <chenjiang_518> | <Cimmeria> | <paxillifer> | <Snowy_Nights> | <SunnyClockworks> | <TheGreatest> | <viridis> | <zostera>
SunnyClockworks: Sawdonia!
zostera: What?
SunnyClockworks: Why the hell was I not informed that you got ENGAGED last month?
zostera: I think I’m well within my rights to withhold details about my life from you lot.
SunnyClockworks: No, no, I get that. What I don’t get is that you told Atropa and Rhynia and not me! Why do they get the juicy details but not your bestest friend Pleuromeia?
zostera: …You’re old enough to be my mother.
SunnyClockworks: I’m forever twenty-five! And even if I were hypothetically your senior, Atropa isn’t any younger than me!
chenjiang_518: Have you considered the possibility that you just weren’t paying attention? This is old news.
SunnyClockworks: Wait, Máotiānshān? Aren’t you supposed to be a Dread Hunt Lieutenant? How the hell do you even have my number? Shouldn’t you be out murdering tyrants or whatever it is the Oneirodeans are supposed to do?
chenjiang_518: I might be a terrifying weapon of a misanthropic not-god, but I still get downtime. As for the number, you gave it to me back in Wǔlóng.
TheGreatest: You all are still hung up about the engagement? I have it on hand that Sawdonia tried asking your Emperor to officiate the wedding!
zostera: HOW IN THE TEN HELLS DID YOU FIND OUT ABOUT THAT!
TheGreatest: Let’s just say that there are some privileges to being Chief Author of the MINASE, ‘Bearer of Radiance’!
viridis: She just asked me!
TheGreatest: …You didn’t have to spell it out like that, Father.
viridis: Now now, Sawdonia has a right to know exactly when and how his privacy is being violated.
SunnyClockworks: Well, I wouldn’t say that -
viridis: And as for the happy couple themselves, I think someone lurking here ought to be filling us in, shouldn’t he?
Snowy_Nights: You have no rights to demand that of me, Atropa.
zostera: Lampranthus…
Snowy_Nights: …Shit.
paxillifer: CALLED IT! I knew there was something going on there! Maru, Cimmeria, pay up!
0806−661: Blast it!
Cimmeria: …Well played. Expect the transfer within the next system hour.
zostera: Wait, why exactly are a Coalition Councillor, a Foundation Director and a Thirteen Stars boss placing bets on my relationships? Shouldn’t you guys be -
<THREAD SCRUBBED BY ORDER OF THE HORIZONIAN INFORMATIONAL SECURITY OFFICE.>
A voice log obtained from Archon Sawdonia’s personal communicator (2219). Note that this conversation occurred just one year after the signing of the Wulandari Accords, officially ending the Cerulean Demise.
