A Place to call home
Humans are a migratory species; one can probably successfully argue that we haven't had a true home since we left the steppes of Africa that we evolved in more than 200,000 years ago. This means that humanity is always expanding, always exploring, and always seeking out new worlds and new places that we can settle in and call home. Whether it's a retread of the tired Manifest Destiny meme (some memes die hard) or Wormhole Imperialism driving the latest colonial effort to claim a system before another Meta-Empire can step in and grab it first, humans are always sitting down roots, planting stakes, and eventually growing into large civilizations before spreading out once the civilization becomes too large. The Evren have noted that migration is perhaps the best population control method that humans have, and perhaps there's some truth it.
Still, humans want home and they want to be comfortable - and they will go far to find that home and comfort. For some, that comfort comes aboard rotation habitats, hollowed out asteroids, or spun torus habitats that look like massive interplanetary bicycle wheels. For others, that comfort can only exist on the surface of a world, with a sky to look up to and a ground to drive stakes into. For the vast majority of humanity, "home" isn't even a physical - for a certain value of physical - place at all, and instead is a sequence of 1s and 0s that run on some massive asteroid-server in the Oort cloud of some distant star, connected to the rest of the civilization via augmented reality and vulnerable only to light lag. It might be in the deepest oceans of frozen water world, the upper cloud decks of a hostile Venusian planet, the muddy flats of a deserted wasteland, or the large lava caverns of huge but mostly hollow moons. It might be in large rotating cylinders that measure miles in length, huge rotating spheres that produce gravity only on a small strip around the equator, or in a cluster of asteroids that has no gravity at all. Or it might be in a digital reality that plays by an entirely different set of physics. Humanity has a wide range of places it calls homes, and it is always looking for, designing, or programming new ones. Categorizing these different, broadly dissimilar groups of concepts is challenging to say the very least. Not everyone stops to think about it, but having categories for them is useful - it allows shorthand reference without detailed description, and creates similar cultural touchstones that everyone can rely upon and understand. Unfortunately, there isn't just one way to categorize these systems; there are countless ways, and any categorization method will leave something out. Still, that doesn't mean humanity hasn't tried; it has - many times over. And each time it does so, it achieves a little more success, even if the categories shift and change overtime just like the planetary bodies that they attempt to categorize. |
Types of Worlds
Human beings naturally seek to stick things into categories, and while these categories are artificial and entirely made up by the human mind, that doesn't mean they aren't an attempt to describe a real phenomenon. In practice, humans call a wide, staggering range of environments home, and not all of these environments are equal - although for some of them, that was the intention when they were made. There are three large, diverse categories that humanity can be found residing in: naturally-occurring planets, artificial worlds and megastructures, and digital realities. Each divides its own confusing maze of subsets from there.
These are worlds that are naturally formed, engineered by nobody but entropy, chance, and the processes of planetary development that have functioned throughout the countless millennia of human existence. The definition of what is and isn't a "planet" gets contentious, but the general consensus for "planet" is any body that is large enough to be rounded without sustaining thermonuclear fusion while also having cleared its surrounding neighborhood. Subdivisions under "planet" become even more contentious, with the original organization of the solar system consisting of terrestrial, gas giant, and dwarf planet - Mercury, Venus, Earth, and Mars being terrestrial, Jupiter, Saturn, Uranus, and Neptune being gas giant (with the latter two a sub-subcategory called ice giant), while Ceres, Vesta, Pallas, Juno, Pluto, Eris, Orcus, Sedna, and countless other bodies were dwarf planets. Other categorizations, such as TNOs and KBOs, described their location. After spreading out, humanity discovered an even more crazy maze of planets than the original 9 in the solar system, and the current widespread paradigm is the Lahotian Taxonomy of Worlds, developed by V.K. Madhumithran and Adarsh Lahoti in the early Interstellar Period.
|
Few worlds come ready made for humanity; in fact, the vast majority of worlds discovered share only one noticeable trait with Earth: they are round. Beyond that, everything else is up for grabs; gravity, presence of a moon, atmosphere, hydrosphere - biosphere if one exists, and advanced biospheres are vanishingly rare (although primitive biospheres that consist of single-celled organisms are not). While the Earth is probably not rare in the grand scheme of the universe, in its own neck of the galaxy Earth is incredibly rare. This makes inhabiting many of these worlds a slow and often times uncomfortable process that requires adaptation over generation, or terraforming (and terraformed worlds straddle this category an the next). However, a more simplistic solution is available: if there aren't enough habitable worlds, just make them. This has lead to the construction of numerous habitat styles; collectively, these are referred to as artificial worlds, although other names are sometimes used: space stations, star ships (if they have their own engines capable of producing appreciable thrust, which many do), and habs. There are countless variations; some of the better known types include O'Neill cylinders, Stanford toruses, and cluster habitats.
|
While a sizeable percentage of humanity occupy physical worlds, that's not true for them. In fact, the vast majority of humanity live in digital realms, and that's the last categorization of world type. Digital realities exist as purely programmed data that runs on large, sometimes dwarf planet-scale servers that crunch the data to produce virtual realms. AIs, AGIs, mind emulations, and the like all occupy this digital space and call it home, and it generally has three different broad categories: overlapping augmented reality, partial simulation, and full simulation. Overlapping augmented reality is where physicals (i.e., those who have a physical body and are not digital) can use augmented reality to interact with the virtual world that digitals occupy; this virtual world is often overlaid on the physical world through augmented reality, producing a "synthetic reality" that allows both digital and physical to interact as if they shared the same space. Nariac's Zov Tigra has the most mature example of this technology anywhere. Partial sims, are those that use design shortcuts to avoid accounting for all aspects of the reality (such as only rendering what the individual is looking at) while Full sims aim for just that: a full simulation of reality.
|
To terraform or not terraformThe issue of terraforming - turning a planet that is unlike Earth into an Earth-like world - is a surprisingly contentious one. Humanity has some experience with terraforming from the Solar System - Mars was finally terraformed after several failed attempts owing to a lack of hydrogen and oxygen, while Venus was fully terraformed after several centuries of effort - but the misses far out weight the successes, since each planet requires its own unique method of terraforming and there isn't a "one-size fits all" approach that can be standardized and then adjusted for costs. Because of this, many private businesses are loathe to involve themselves in the effort; it takes to long to turn a profit and few prefer investments that large. It just isn't a sound investment strategy when you can dismantle an asteroid and produce thousands of habitats providing more surface area, and capitalism demands efficiency. Of course, government systems and anarchist collectives don't have to be efficient; they just have to want something done bad enough to do it. Thus, post-capitalist companies like Alhambra have made a name for themselves; they use reputation and slow money rather than fast money to turn terraforming into a viable business model, and the results speak for themselves, with Bluefall being their crown jewel. Beyond the economics, there are questions of ethics. Preservationists argue that humanity does not have the moral authority to run around the universe altering worlds to fit its needs; every world is unique, and every world altered to resemble Earth is a unique planet that is lost. On the other hand, there are those who argue that unique or not, a ball of rock is resources that humanity could be using to extend the lifespan of its civilization well into the Dark Ages, after the Stellariferous era is done and the universe has gone dark. To them, terraforming is a waste of resources, as well; humanity should be stockpiling now for the end of time later. These individuals are most often digitals and prefer a digital existence to a physical one. Not everyone enjoys living on a space station, though, and for a lot of worlds, they are little more than barren, uninhabited wastelands. Most can see the moral argument when there is native life, but when there isn't? In that instance, nano-ecologists argue that humanity has a moral duty to make the universe as friendly and applicable for life as possible, since it has the technology to do so and to leave the universe a cold, hostile, and uninhabited place represents a moral failure - a dereliction of duty; an abandonment of future generations. If a person had the technology to make their home and their neighborhood a better place, most would argue they should. The same logic applies to terraforming, nano-ecologists hold. And so the debate rages. |
The Lahotian Taxonomy of Worlds
There are zoo of different physical planets in the Verge and Bleed, and categorizing them all generally produces gaps and weird overlaps. However, humans being humans, we seek to understand and categorize anyway, and so several methods have been adapted, the most widespread of these being the method developed by planetary scientists Vasantha Kumar Madhumithran and Adarsh Lahoti, called the Lahotian Taxonomic method. V.K. Madhumithran and Adarsh Lahoti used a mix of characteristics in their categorization, ranging from size and mass to composition and atmosphere to achieve their categories, which divide planets up into a number of regimes. While theirs is the most widespread, however, it's far from the only one, and individuals can still run across some older systems as well, such as the Sudarsky classification system for gas giants (which Madhumithran and Lahoti made some use of). And their system only briefly discusses the nature of artificial worlds and habitats, including a number of different megastructures such as shell worlds, McKendree cylinders, Bishop Rings, and the like.
The Lahotian Taxonomy of Worlds is one of the most widespread of world taxonomies. It breaks worlds down into several discrete categories, and then further divides them according to various physical characteristics such as mass, composition, size, temperature, and the like. While far from a perfect system, it is a complete one. In addition to issuing taxonomies, the company that owns the rights to the taxonomy, ML Taxonomies, also issues maps that it constantly updates with new information; these are 3D interplanetary maps that use the unique Kelesta™ software coding to project a real-time volumetric display of the world based on the ship's current coordinates in relationship to the star (providing a real-time image is available; otherwise, it will project the last image of the world that it has on file, or a blank sphere if there isn't one on file). Licensing it is highly recommended for those who spend a great deal of time in space and travelling from planet to planet.
The broad categories of world are Earthlike worlds, Gas Giants or Jovians, Hostile Terrestrials, Ice Dwarfs, Ice Giants or Neptunians, Ice Worlds, and Rocky Worlds. Each category is further divided into subcategories.
The Lahotian Taxonomy of Worlds is one of the most widespread of world taxonomies. It breaks worlds down into several discrete categories, and then further divides them according to various physical characteristics such as mass, composition, size, temperature, and the like. While far from a perfect system, it is a complete one. In addition to issuing taxonomies, the company that owns the rights to the taxonomy, ML Taxonomies, also issues maps that it constantly updates with new information; these are 3D interplanetary maps that use the unique Kelesta™ software coding to project a real-time volumetric display of the world based on the ship's current coordinates in relationship to the star (providing a real-time image is available; otherwise, it will project the last image of the world that it has on file, or a blank sphere if there isn't one on file). Licensing it is highly recommended for those who spend a great deal of time in space and travelling from planet to planet.
The broad categories of world are Earthlike worlds, Gas Giants or Jovians, Hostile Terrestrials, Ice Dwarfs, Ice Giants or Neptunians, Ice Worlds, and Rocky Worlds. Each category is further divided into subcategories.
Earthlike Worlds
Earthlike worlds, also called Gaian worlds, divide into two broad subcategories with a number of smaller categories that fall under those.
Garden worlds are the most Earthlike of the Earthlike; these are worlds who are large enough to retain thick atmospheres and retain large amounts of water on the surface. These help mediate the climate to produce a climate that humans can find not only bearable but also pleasant. Garden worlds are generally dominated by single-celled organisms, although worlds where multicellular and even advanced life aren't unheard of, even if they're rare. Because single-celled life is so common but multicellular life is so rare, and because Garden worlds are actually relatively common, it's lead many to conclude that the leap from single-cell to multicell life is the "Great filter." Earthlike worlds are staggeringly rare - there's only a handful of them known; the majority of the worlds that are called "Earthlike" are actually ocean worlds that have undergone light terraforming. Ocean worlds are worlds that have a thick atmosphere and plenty of water, and these help to regulate a planetary temperature that is amendable to life. However, what they lack is life of any kind, often times because their geology is inimical to it (Bluefall, with its lack of a phosphorous cycle, is a prime example of this). As a result, the atmospheres of these worlds may contain oxygen, but it's only a small amount and is the result of photodissociation of water molecules in the upper atmosphere of the planet. Earth was an example of this type of world billions of years ago. It's important to note that the distinction between an ocean world and a garden world is the existence of native life; not any physical category. Beyond those, there are a number of other categories that are worth noting as well; these are subcategories. |
Bathypelagic gaiansA bathypelagic Gaian world is an Gaian world where more than 90% of the surface is covered in water. Often, there are several ways this happens, which leads to one of the handful of subtypes. If the erosive processes manage to outpace the tectonic processes on the planet and as a result, the planet has a low surface relief which results in much of the planet being covered in water, then they are called epipelagic worlds. Often, the ocean depth are not extreme; while the only planet may be covered in water, the ocean is only one or two miles deep at the deepest. Mesopelagic worlds are worlds where the tectonic processes never created much land to begin with, or are super-earths that simply attracted more water during creation. These planets often have sparse islands, but the oceans are otherwise very deep, between 5 to 10 miles in some cases. Hadeopelagic worlds are superearths with no land and oceans that can be up to 30 miles deep, if not more. A fourth category, called Stereopelagic worlds, exists, but these are actually cold gas dwarfs that slipped into the habitability zone of their star. Famous Example: Antigua |
Desert gaiansThese are also called xeric Gaian and are the result of a planet with less than 40% of its surface covered in water. Xeric Gaians are often smaller than Earth and orbit closer to their star; this means they have less gravity, and so while they may form with water on the surface, the proximity to their warming star and the smaller size means they sometimes have a hard time keeping it. Xeric worlds are also very young; often they're in the process of transforming into a Venusian or Mars-like world. It can actually be difficult to distinguish a young xeric garden world from a young Arean world, and so the distinction is often immaterial. Xeric worlds can also form if there is a lot of water trapped below the surface in massive underground reservoirs that appear on the surface in oases and springs. While they often don't have a lot of oxygen, they can sometimes posses oxygen-producing cyanobacteria analogs in what water they have; in other instances, they may be an older garden world in the process of losing its water, and any oxygen it has is the result from an earlier period in its history. Famous Example: High Mojave |
Neo-GaianNeo-Gaians are a classification that specifically includes all terraformed worlds. These worlds were originally oceanic worlds or Arean worlds that were amendable to terraforming (usually young Areans), or one of the other Gaian types mentioned so far that lacked native life but otherwise had conditions that could allow for the development of Earth-based biochemistry. Terraforming has only recently become a big business with the successful terraforming of Bluefall and Alhambra's investment scheme of using slow money to finance these massive undertakings. Obviously these worlds are as close to Earth as is physically possible without producing an Earth-like from scratch (although the God AIs were known to do that). Bluefall is the poster-child for this type of world and is the best known Neo-Gaian in the Verge and Bleed (it was originally an oceanic world). Mars is another example of a Neo-Gaian world. This category only includes worlds that have been terraformed; artificial habitats, terraria, artificial worlds, megastructures, and the like are not considered Neo-Gaians. Famous Example: Bluefall |
Palustrial GaianOne of the rarest types of Gaian worlds, palustral Gaian worlds are similar to xeric Gaians in that they lack a lot of water on the surface. However, they possess a great deal of water just below the surface, and with low water tables and erosive effects that outpace tectonics ones, this means that a low surface relief that lets water seeps up easily through the surface creating vast shallow swampy, muddy terrain with no mountains. The result is that anywhere from 30 to 50% of the planet is covered in water, and these worlds often hose expansive bogs, wet lands, and depending on the temperature and latitude, tropical or subtropical swamps. It's an interesting note that every palustral Gaian encountered so far as had native life, sometimes advanced life, which leads some scientists to assume that Earth developing life was actually a one-off fluke event that life is much more common on these worlds without extensive oceans. However, the worlds remain very rare, with only 10 to 50 recorded. The poster-child for this world time is the world of Alandricht, which may be the best known palustral world in the Verge and Bleed. Famous Example: Alaundricht |
Snowball GaianSnowball Gaian worlds are often transitory phases that a Gaian world progresses through. The usual cause for this type is continent formation blocking ocean circulation, which results in a drop in temperatures and a global cooling feedback loop as more ice forms that increases albedo, resulting in more ice forming that then increases albedo, and so forth, until the whole planet is frozen. However, snowball Gaian worlds can also form as permanent fixtures of a solar system; they're usually found in the systems of K-type stars, where the Gaian world can retain an "earth-like" temperature but orbits far enough that water on the surface is frozen, even though water under the surface remains liquid. These worlds are often prime targets for terraforming since all they require is warming, which can be done by introducing CO2, CH4, and other green house gasses into the atmosphere, trapping heat under the surface and melting the ice. An interesting variant is the Polyphemian snowball, which are found around red dwarves and are identical to the Polyphemian Europan worlds. Famous Example: Hudson |
Tidally-locked gaiansTidally locked garden worlds are the most common of the Gaian worlds (they're the most common world type period, given the prevalence of red dwarf stars). A tidally locked Gaian world is a garden or ocean world that orbits around a red dwarf star; in order to be in the zone where liquid water transitions to ice, the Gaian world has to orbit very close to its parent star. The result is that the Gaian world ends up tidally locked, with one side permanently facing the parent star and one side facing away from the parent star. These Gaians come in two types, and in both instances the only inhabitable place on the entire star is the terminator region that tends to follow the prime meridian, with the angle of the star depending. The first type are called Zephyr worlds; they have a large substellar desert and an antipodal ice sheet, with a thin atmosphere that has a hard time circulating heat. The next type are called twilight worlds; they have a thick atmosphere and thus, have a relatively uniform temperature even if they lack a day-night cycle. The third type are typhoonic worlds, with a large substellar hurricane. Famous Example: Aratis |
Gas Giants and Ice Giants
Gas giants are Jupiter and Saturn-like planets; these are sometimes called Jovian worlds, and are often much larger than even the largest terrestrial world, sometimes many times the diameter of one. Their atmosphere is a massive one dominated by hydrogen and helium, and there is often no surface, just layers of clouds. There are several distinctive categories for these types of worlds, based mostly on size and composition.
Jovian worlds are as described above; they have an atmosphere that is majority helium and hydrogen, making them massive gas balls. They are usually 5x the size of the Earth at least in diameter, and their composition includes less than 50% water in the atmosphere. Neptunian worlds are worlds that are similar to gas giants but differ in one key respect; they have more than 50% water in their atmosphere, and are often an intermediary between an oceanic world and a gas giant. Those that form beyond the snowline often have a variety of other ices in their atmosphere as well, and if there is enough carbon, may even have an outer mantle of super-conductive diamond around their core. Nebulous worlds, also called Gas dwarfs, are like Jovian worlds in most respects - an atmosphere of mostly hydrogen and helium, less than 50% water in the atmosphere (often far less), but their size is only 2.5 to 5x the diameter of the Earth. They are often gray or purplish gray in color. Gas dwarfs, Neptunian worlds, Jovian worlds, and water worlds all occupy spots on a spectrum, and are not necessarily fixed types. There are different types of Jovian/Neptunian worlds, however, detailed below, organized according to the expanded Sudarsky method common to the Lahotian taxonomy, and are usually named after their color or components in their atmosphere. |
Type I - CorundumExisting at temperatures above 2200 K, these are some of the most extreme environments ever encountered by humanity. They have clouds of calcium titanite and corundum, often with titanium oxide haze. On these worlds, it rains liquid corundum (that is, liquid ruby and sapphire) and liquid calcium titanite. These worlds are so extreme and inhospitable that humanity, a species that has managed to settle the corona of G, K, or M-type stars, stays away from them and generally has nothing to do with them. They're sometimes called Rubies and those who are uneducated or simply lack all the data of the planet can confuse it for a brown dwarf. Often, these worlds don't last much longer than a few million years before their atmosphere burns off and they become a chthonian world. The extreme heat drives equally extreme weather, and not only does it rain liquid ruby on these worlds, it does so sideways, at windspeeds nearing the speed of sound. |
Type II - SiliconExisting at temperatures above 900 K, these gas giants often have upper cloud decks formed of vaporized silicon and iron oxides. These worlds are often so hot that they glow on their night side due to thermal radiation, and the dark coloration is as a result of iron oxides and other vaporized metals in the upper cloud decks; this further traps heat, which causes them to expand. They're also sometimes called puff-ball worlds or puffy worlds. On these worlds, whenever it rains, it rains liquid sand, and as a result of the general hostility that these worlds represent, humanity typically leaves them alone. There are two subtypes: comet worlds, which have a long, comet-like tail that trails behind them like a comet's coma, and blue-gray worlds, which are a similar temperature and composition but lack the layer of metallic clouds in the upper atmosphere and so take on a silvery blue coloration instead of the dark blackish-gray color. |
Type III - AlkaliAn alkali gas giant exists at temperatures between 900 and 650 K, with the precise composition varying, although at all temperatures they have clouds of alkali metals such as sodium and potassium. Towards the cooler end, rubidium, cesium chloride, and other chloride and sulfuric components become common in the atmosphere. Since both rubidium and cesium are radioactive, this means these planets, which are cooler than their fellow hot-jovian and hot-neptunian worlds, have the draw back of being dangerous radioactive as well. This means that as with other hot jovians (Types I - IV), Humanity tends to leave them alone, although some specially designed cybershells may be able to delve into the atmosphere of these gas giants, withstand the heat and pressure, and mine them for their valuable stash of alkali metals, or simply use them as a place to experiment. |
Type IV - AzureAzure neptunians and jovians exist between 350 K and 800 K, and tend to have atmospheres think in methane. This is why their atmospheres are often so blue; a the temperatures that they form, these gas giants cannot form water ice and other condensates in their atmosphere, which makes them completely cloudless. Their cloudless nature often exposes the methane to Rayleigh scattering, which results in the atmosphere being exceptionally blue, hence the name. While these are often not habitable, on the cooler end, the planet may be able to form clouds of water ice at the poles, and as the planet orbits its star, it can go through "ice ages" as the water-ice clouds emerge from the poles and stretch down to the equator, before clearing up again as the planet warms. As a result, these gas giants are often habitable at the polar regions, which by Earth standards is often still quite hot 350+ Kelvin). Famous Example: Brahe |
Type V - WaterWater jovians and neptunians are too warm to form clouds of ammonia and hydrogen; instead, they form clouds made up of water vapor. These gas giants often appear at temperatures around 250 K, which many will note is precisely the correct temperature for human life. What's more, these gas giants can also have a significant part of their atmosphere be oxygen as a result of photodissociation in the upper atmospheres, so on some smaller gas giants and conventional neptune worlds, habitation is often carried out using floating cities, or aerostats, just like on Venusian-like worlds, although on water jovians and neputnians they don't even need to be sealed much of the time. One of the most ambitious terraforming projects ever is the water jovian Zell, which is in the process of "cloud terraforming." The moons of these gas giants are often inhabitable. Famous Example: Harriot, Mokoia, Nu-2 Canis |
Type VI - AmmoniaAmmonia gas giants appear at around 150 K, and are the most common type of gas giant and what most people (except those who live on gas giants) picture when the term "gas giant" is mentioned - Jupiter and Saturn are typical (albeit wetter than average) ammonia gas giants. On these worlds, clouds of ammonia form in the atmosphere, and together with complex compounds of sulfur and carbon, given these gas giants a reddish brown or yellowish brown composition; many gas giants actually lack the archetypal "cloud banding" that's present on Jupiter owing to various methane hazes and aerosols in the upper atmosphere. Depending on the size and gravity (and magnetic field) of these gas giants, they may be colonized using floating cities, similar to the way that water jovians and neptuanians are colonized. Famous Examples: Jupiter, Saturn |
Type VII - MethaneExisting between 60 and 80 K, these Gas giants (although they are mostly neptunians; methanian gas giants are relatively rare), these gas giants often have turquoise atmospheres. The coloration is the result of moderately dense methane atmospheres and organic hazes in the upper atmosphere; the planet Uranus is characteristic of this type in its summer hemisphere. While these can be colonized with floating cities, they are often left uncolonized or colonized from orbit (one notable exception was Uranus itself, which feature an orbital ring and large chandelier cities that dipped into the upper atmosphere, similar to the cities on water worlds like Antigua. Such structures are rare, however, since they require a great deal of resources). If the planet is a neptunian, odds are good that it rains liquid diamond in the lower atmosphere. Famous Example: Uranus |
Type VIII - Cold methaneBelow 60 K, it's too cold for condensates to form and as a result, the atmosphere is once again a very clear and deep bluish color (although storm bands may form and these can be white or dark blue). In some instances, their blue is muted as a result of aerosols and organic hazes in the upper cloud decks. As with Type VII, these gas giants are sometimes colonized with floating cities, although just as often they're colonized from orbit or using their moons, which tend to make for easier targets. Neptune is the best example of this type of world and the one most people think of (and the one that lent its name to the entire concept of the "neptunian world"), although in the instance of it being a jovian, they are sometimes called "ice jovians" or "ice gas giants." Famous Examples: Neptune |
Hostile Terrestrial
Hostile terrestrial is a broad term that covers any terrestrial, or rocky world, that is large enough to maintain an atmosphere that features interior differentiation similar to Earth, but for whatever reason, be it atmospheric composition, temperature, geology, or a combination of the three, the planet is profoundly dangerous for unprotected humans and requires specialized gear to even contemplate attempting to settle. There are several categories of world that fall under this broad header. In general, there are two broad types:
Greenhouse worlds are worlds with thick atmospheres and sometimes plenty of water. However, at some point, geochemical processes ran out of control, and the planet warmed considerably as a result. In some cases, there is surface water, while in others, there is none; similarly, in some cases, they can support surface life - in others, none. Hydrocarbon worlds are worlds that retain a thick atmosphere, often with plenty of water and light volatiles, but are so cold that the water is frozen, or the other otherwise interacted with the native geochemistry and was used up, ensuring that water-based biochemistry can never arise. Some subtypes of this category are exceptionally common - Venusian worlds exist in practically every system - while others are very rare. This rarity often plays into their favor, since since they become exceptionally well known because they're so rare. Some of the best known planets in the Verge and Bleed - for instance, Yellow Sky (a chlorine world), Dallol (a vitriolic world), Danakil (a vitriolic world), and Green Sunrise (a chlorine world) - are among the more famous of these world types. |
Ammonia worldThe archetypical hydrocarbon world, ammonia worlds are worlds with frozen water that functions like a crust, similar to what one sees on some ice planets, but they have maintained an atmosphere of largely ammonia and methane, and often have oceans of liquid ammonia mixed with water, since liquid ammonia/water mixes have a much lower freezing temperature than standard water. These worlds are relatively rare, given that the compound that makes up the majority of their geochemistry, ammonia, breaks down under UV light. As a result, it's rare to see these worlds types around anything other than a cool M-type star which doesn't produce a great deal of UV radiation, allowing the material to form in the atmosphere. In at least one instance, such a world has produced ammonia-based biochemistry; this biochemistry is highly exotic (and highly flammable) so it's often kept out of oxygenated environments. Often, their oceans are actually blue, since methane and ammonia scatter blue light, but the oceans are rarely pure and sometimes salts can change the coloration, usually to iridescent green or brown. Famous Example: New Vesta |
Carbon WorldCarbon worlds are the second type of hydrocarbon world, and they can exist at any temperature. Their cores are often iron and steel-rich, surrounded by a sea of molten silicon carbide and titanium carbide above which is a layer of graphite, often with a substratum of diamond that's hundreds of miles thick, and during volcanic eruptions, they spew diamonds. This results in diamond and titanium carbide serving the same role that basalt and other mafic rocks serve on Earth, and would result in mountains made of diamond. While they can occur at any temperature, weather is only possible on these worlds if the temperature is around 300 K; at that temperature, oceans of tar, oil, and petrol can form. Primary cold carbon worlds have carbon dioxide atmospheres with carbon haze; hotter ones have a primarily nitrogen. These worlds lack water, making them difficult to settle, although sometimes wandering mystic tribes select these worlds for their odd beauty. Sometimes, these planets are targeted for mining operations; carbon is an exceptionally versatile element, and used in a great deal of things. Famous Example: Graphos |
Chlorine WorldWhile they were a popular fixture of science fiction for generations, these worlds are fabulously rare and require specific circumstances within the interstellar medium in order to produce (to wit, stars tend to favor lighter and even-numbered elements in nucleosynthesis; chlorine is a heavy and odd-numbered element, so to form it requires alpha-process rich elements like sulfur, argon, calcium, titanium, chlorine, and the like to enrich the local interstellar medium). These worlds have a higher metallicity, which means a greater presence of heavy metals in their crust, but it also means they tend to be larger, attracting thicker atmospheres that walk up to the edge of being a Venusian world without going over. These worlds also tend to have low surface relief, since few rocks can withstand the hydrochloric acid-based oceans. In addition to a surface of primarily silicates and clays, it also means that dangerous radioactive elements are exposed as well, making these planets radioactive. This, combined with the immense heat, heavy gravity, and local acidity, makes them rare targets for settlement efforts. They are a greenhouse type planet. Famous Example: Yellow Sky |
Promethean WorldConventionally a greenhouse type when they have an atmosphere, Promethean worlds are worlds with a thin crust and a great deal of volcanic activity. In many instances, these planets don't have detailed surface maps so much as they have weather reports, with the thin crust constantly shifting day-by-day. In instances where these are small worlds, it's usually a result of tidal flexing - Jupiter's moon Io is a good example of this. In larger worlds, it's because they're very large - generally about 5 to 10x the size of the Earth, which results in an interior that is so roiling and violent that it's barely constrained by the thin crust. Supervolcanic eruptions reshape the surface daily, while earthquakes split the crust like dried skin on a human heel. If they have atmospheres, it's often atmospheres enriched with sulfur and other dangerous chemicals, and while those chemicals are unsafe to breath, the air is often so superheated that it would destroy the lungs long before the sulfur could. In some cases, these can resemble Venusian worlds, and allow for similar habitation methods. |
Venusian WorldVenusian worlds are the classic greenhouse planet. This worlds are usually the result of the planetary crust being unable to split into tectonic plates, prohibiting the tectonic processes and various cycles like the carbon cycle. Then, over-exposure to heat results in the planet warming to the point where the carbon gets trapped in the atmosphere, instigating a feedback look that results in a world with crushing surface pressures comparable to the bottom of an ocean, and dense yellowish white or tan-colored clouds that have an otherwise high Bond Albedo. Naturally, these worlds are named after Venus, which is the best known world of this type. Towards the end of their parent star's life, most Gaian worlds take a detour through this world type before ending their life as an Arean rockball. Venusian worlds are common targets for colonization, since their dense atmosphere usually allows floating habitats filled with breathing air to stay aloft in their atmosphere. Venusian planets that have no water on the surface are called dry Venusian; those with are called wet. Famous Example: Venus |
Vitriolic WorldVitriolic worlds are often classed as greenhouse worlds owing to their extreme surface temperature, often 300 K or higher. Like chlorine worlds, they need a number of very specific events in order to form, otherwise the result will be a Venusian world, and this is in part due to sulfuric acid being a rare chemical and in part due to requiring highly specific sets of circumstances, such as the world being subject to intense photodissociation from the parent star - but not too intense, or it will trigger a run-away greenhouse effect. Given that their creation is such a fine balancing act, most worlds of this type are seen as the result of terraforming by an alien unknown species. That these worlds frequently have advanced life that is all genetically related is the nail in the coffin. From the surface, these worlds tend to be a mix of the odd and the familiar; their atmospheres are often vivid blue with some diffraction near the horizon due to atmospheric sulfur aerosols, but their oceans often have the viscosity of molasses. All of the dangers present on chlorine worlds are present here, as well. Famous Example: Dallol |
Ice Worlds
The "ice world" and "ice dwarf" categories cover a wide range of different world types, all unified by a single aspect: they're very cold and made mostly of ice. The exact composition, size, and whether they have and to what degree they have an atmosphere depends on the precise category. All of these worlds tend to look similar from the outside, with differences relating mostly to core structure.
Ice Dwarfs are worlds too small to retain a significant atmosphere but it is cold enough that it retains rich deposits of water and other volatiles. Some may also retain a subsurface ocean if there is enough radioactive heat or tidal flexing (as is often the case with moons of this type). This subtype is also called the Europan planet. Ice Worlds are sometimes large enough to retain their atmosphere, but in many cases these atmospheres (which are almost entirely composed of nitrogen) is frozen to the surface of the planet. These are called Hadean worlds. In other instances, the nitrogen atmosphere is warm enough to stay in the air, and in this case, it helps create a thick coat around the surface of the planet full of organic hazes. Sometimes, surface oceans of ammonia, methane, and other hydrocarbons may be present; these are called Titanian worlds. Titanian worlds often have cores that are mixed ice and rock, as opposed to solid metal core. The last two world types in this category are Plutonian worlds and Sednian worlds, and both are superficially similar to the Hadean world. However, the difference is often in the core and geological activity; Hadean worlds, Titanian worlds, and Plutonian worlds are all geologically active while Sednian worlds are not. Like a Titanian world, a Plutonian world has a mixed ice-rock core, but like a Hadean, it has an atmosphere that is almost completely frozen. The Sednian world is distinctive from both types; it features a core that is almost entirely composed of ice. Famous examples: Europa, Pluto, Titan, Yellowstone |
Polyphemian SubtypePolyphemians are a special class for worlds of this type. These are also sometimes referred to as "eye-ball" worlds because they look like an eye. These are ice worlds (although in some rare instances they may be partially thawed oceanic Gaians) that are not only large enough to have an atmosphere, but they often sit at the very edge of their habitability zone. Found exclusively around M-type stars, their unique appearance is the result of tidal locking; the like a tidally locked Gaian, one hemisphere is constantly facing towards the parent star, and the other away from the parent star. The hemisphere that faces the parent star has almost totally thawed, revealing the large subsurface ocean that lies under the planet's icy surface.
Whether or not a Polyphemian has an atmosphere depends on the size, distance form the parent star, and the core composition. Most Europan worlds have an ice core, which means that most Polyphemians do as well and thus, lack the magnetosphere necessary to retain a thick atmosphere. sitting as close to their parent star as they have to in order to produce the substellar ocean. However, there are a subtype of Polyphemian that have ice-metal core mixes, like a Hadean or Titanian world. These worlds often retain thick atmospheres, and their natural size assists. Perhaps most interesting is that these worlds may contain oxygen atmospheres; if they do have a rick oxygen atmosphere, it's a result of photodissociation. The fact that while cold their substellar hemisphere is often no colder than nights in Antarctica (compare their antipodal side, which has temperatures dipping below 100 kelvin in some cases) sometimes makes these worlds optimal targets for settlement; they have a wealth of volatiles, water, and the like already there for humans to make use of. Famous Example: Polyphemus |
Rocky Worlds
Rocky worlds occupy a conceptional space that's somewhere between hostile terrestrials, Gaians, and ice worlds and share many of the features from each. Like hostile terrestrials and Gaians, rocky worlds tend to have a wholly differentiated interior, with a mantle, core, and crust. They also have a surface composed of hard silicates, similar to hostile terrestrial worlds and Gaian planets. Like ice worlds, they very often have little to no atmosphere, or if they do, the atmosphere is very often the product of outgassing. The big distinction often lies in the magnetic field and geology; where Gaian and hostile terrestrial worlds are geologically active in their own way, and often have magnetic fields, rocky planets are not geologically active and they lack magnetic fields. This means that earthquakes, volcanoes, and the like are often not the product of interior geological activity; in the rare cases where they do exist, they're the results of tidal pressures from the parent star or the body that they orbit around, or may be a result from cooling deep within the planet. In short, if one considers a tectonically active world to be "alive," then rocky worlds are dead.
Rocky worlds tend to divide into two categories: Coreless rocky worlds are rocky worlds that formed with little to no core, or with very small metallic cores. These worlds are common around older, lower metallicity stars and because they lack a core, often lack the ability to retain an atmosphere. Cored rocky worlds are those that have large metallic cores, and as a result, are often popular targets for mining ferrous materials. |
Arean worldIt can sometimes be hard to tell an immature Arean from a mature Gaian planet; often, in their early stages of development, these planets have atmospheres and even liquid water on the surface of their planet, but because their core is so small they eventually die, in geologic terms, and they lose their atmosphere and oceans, leaving behind a barren world. A mature arean is often called a Marslike; these are among the most common planets in the universe. Each Marslike has its own unique set of circumstances that lead to its birth and ones that have surface gravity comparable to Earth are sometimes marked as potential terraforming candidates. Controversially, Areans are often classed in the "coreless" category, because while they have cores, their cores are often very small compared to their mass given some of the other rocky types. Areans are often popular worlds to target for colonization all the same, given that they can be easily terraformed. As with most of these world types, the Mature Arean is also often confused with a post-Gaian and in many ways, they're often the same thing - the end result of an Gaian who dies geologically is usually a mature Arean world. Famous Example: Mars |
Chthonian WorldThe chthonian world is often large enough to retain a thick atmosphere, but are so close to their parent stars that almost all of the volatiles have been striped away. There may be a tenuous atmosphere in some cases, but it's likely to be composed of vaporized metals like sodium or similar compounds. Often, these worlds are the result of a gas giant that strayed to close to its parent start and had the atmosphere blown off; generally a Type II - IV meets this fate, especially if they have a coma. Sometimes it can be a terrestrial world that migrated inward. Often times, the surface of these planets consists of superheated rock, otherwise known as lava, and they can resemble a Promethean world, although where Promethean worlds can have an atmosphere, chthonian planets rarely do. Colonization of this world is generally difficult and rarely worth the effort, although corporations looking to extract rare and exotic materials from gas giant cores will often mark the planets and use specially designed cybershells that are tele-operated from orbital stations several AU away, or that contain LAIs and NAIs who are self-directed and process the minerals anyway. |
Ferrous WorldFerrous worlds are planets that are usually 80 to 80% core, and are composed siderophile elements, including iron itself. Since these worlds form closer in to their young and active parent stars, much of the usual planet building material is blown away, leaving behind a surface that is mostly core. The distinction between a chthonian world and ferrous world can seem immaterial but often they have different chemical compositions; for instance, ferrous worlds almost never have water in their curst, while a chthonian world that formed further out and drifted in can have a sizeable amount of water trapped under its surface. Ferrous worlds also tend to orbit further away from their parent stars than chthonian worlds do, although around sun-like stars they orbit well within the radius of Mercury. While the planets are dead now, they are often heavily cratered and show signs of extensive geological activity in its early days as a planet. The only atmosphere these worlds often have is a trace element of helium, that is both stripped away and replenished by the solar wind from the parent star. As with chthonian worlds, they are popular mining targets for corporations. Famous Example: Volos |
Mercurian WorldsMercurian worlds are rocky worlds that orbit close to their parent star. Unlike ferrous worlds, these worlds maintain a lighter, rocky crust in addition to their massive core, which may compose up to 80% of the planet's mass. Like ferrous worlds, they are composed mostly of iron and siderophile materials and elements. They often show sign of primordial geological activity, and their atmospheres are often vaporized sodium and hydrogen, the latter of which is replenished due to the solar wind of the parent star. Mercurian planets occupy an uneven space between silicate worlds and ferrous worlds. They can form in a manner similar to a ferrous world or, as is the case with Sol's own Mercurian world, be the result of a catastrophic collision that blew away much of the early planet forming materials. While ones that are 2.5x or larger than Earth are not unheard of they are rare; Given their size, they should have thick atmospheres, but instead are dense, high-gravity rock balls. Outwardly they may resemble Chthonians, which similarly tend to be large, but unlike chthonians, they lost their atmosphere during their formation, rather than having it blown away afterwards. Famous Examples: Mercury |
Selenian WorldsSelenian worlds are what most people think of when they think of coreless worlds. These are the archetypal coreless world, often forming around low-metallicity stars or as moons around terrestrial planets (such as the case with the original Selenian world, Earth's Moon). They have almost no heavy metals, no geological activity, and are functionally "dead" in a way that Arean worlds never were, because Selenian worlds were never "alive" in the first place. If a Selenian has any evidence of geological activity in its past, it's often the result of a traumatic creation; for instance, two large bodies that collide and merge together throwing off enoguh crust material so it accumulates into a Selenian world, as is the case with Earth's moon. These worlds are often heavily cratered, because there's little to no geological activity to remove the craters, and they have no atmosphere to speak of. They may still experience outgassing, however. This world type was popular for early generation artificial world creation, where the God AIs used black holes for their non-existent core. Famous Examples: Luna |
Silicate worldSilicate world is a catchall used to describe any rocky planet that doesn't fall into one of the above categories: they have cores, however small, they orbit to far from their parent star to be considered Ferrous or Mercurian, there's a sizeable crust but no evidence of geological activity and there's no evidence of any surface water, although they are large enough to retain a very thin atmosphere. This atmosphere isn't thick enough to retain surface water and the planet is often too war for the volatiles to freeze into solids, which results in them being removed due to the solar wind. Silicate worlds, like Mercurian worlds, are rarely as large as Earth, with ones larger incredibly rare. Generally speaking, one finds silicate worlds in the habitability zone around stars or near the outer edge; more than one silicate world has trick an astronomer into thinking that they've found a potentially habitable exoplanet that turns out to be a dead rock with very little to it. Since they often lack large cores, they aren't even good for mining raw minerals or resources, and so these worlds are generally overlooked. They're sometimes called Vestian worlds, after the asteroid Vesta they resemble. |
Unique World Types
While the categories above cover most of the common world types, there are a few outliers that don't fit in any particular category and are worthy of mentioning because they do come up from time to time. They are unclassified by the Lahotian Taxonomy, and are often bundled into a separate category called "exotic worlds."
Smertrian Worlds
Smertrian worlds form in systems that have a high metallicity and almost always have a high gravity, a result of the planet forming with a core that is anywhere from 80 to 100 or more times as dense as the Earth's core. Owing to their high gravity they always retain a dense but compact atmosphere, since that slows the escape of even lighter gases like helium and hydrogen. While these planets can form anywhere in the system, it's more common to find them rotating close to their parent star, since they formed further in on the planetary disk. Hot Smertrian worlds are often called "hell worlds" and resemble the hottest of the hot Jovians. In fact, it can be difficult to tell a Smertrian world from a Type II or Type I Jovian; direct measurements of the core are needed to determine the type. They are also sometimes called "Super-Neptunes," but the type is named after Smertrios (HD 149026b), the first planet of this type to be discovered.
Underneath the dense cloud layers they often have a mantle of high-pressure ice, followed by an out core of silicates and an inner core of iron, although the specifics can vary greatly from planet to planet. The gravity on these worlds as a result of the amount of iron in their core can be as high as 10 g standing on the surface of the core (which would be the only place to stand, since they are functionally miniaturized gas giants). In practice, Smertrian worlds sit at the boundary between terrestrial planets and gas giants in terms of physical make up; the atmosphere is composed almost entirely of compressed gas, like most gas giants, but unlike most gas or ice giants, Smertrian worlds have cores that are made from iron, not just rock or ice. Famous Example: Smertria |
Stereopelagic
Stereopelagic worlds are the fourth category into which fully water worlds fall; epipelagic, mesopelagic, and hadeopelagic are the three categories that are often included under the label of Earthlike. However, the fourth label, Stereopelagic, is often anything. Even with the hadeopelagic, there is still solid land; the oceans are only about 30 miles deep. With a stereopelagic world, there is no land; the oceans become extreme hot and the pressure crushing the further down one goes, until the water transitions from a liquid into a high-pressure state of ice. This ice wraps around a usually ice or rocky/ice core, since often these worlds are formed with cold ice giants with plenty of water slip into a warmer orbit around their parent star and that warms the volatiles enough to produce a surface where the global ocean gradually transitions into a high-pressure ice mantle.
These worlds are often prime targets for colonization because they have oxygen-rich atmospheres; photodissociation splits hydrogen from oxygen in the upper atmosphere, and while on a normal terrestrial planet the oxygen is usually absorbed into the crust, on these worlds there is no crust to absorb into, so it remains in the atmosphere indefinitely. However, many of the worlds are uncomfortably warm due to the greenhouse effect that water has on the atmosphere; while solar shades can cool them, few have the capability to put them up. While these worlds are rich with oxygen, it's rare for them to support life; nutrients are dilute and diffuse, and so there's no place for life to gain a toehold. There aren't even vents along the ocean floor for them to gather around and feed from, making these worlds often very dead in terms of native biota. |
Hot Stereopelagic
Hot stereopelagic worlds are an entirely different beast from the standard stereopelagic world. These planets are often hotter than 212 degrees Fahrenheit, and they tend to orbit well inside of their parent star's Goldilocks Zone. Like their Stereopelagic cousins, these worlds form a mantle of ice around their core, but unlike their Stereopelagic cousins, the atmosphere is so dense and crushing that it is impossible to tell where the atmosphere ends and the ocean begins, and where the ocean ends and where the mantle begins. These worlds keep their oceanic layers because of the high atmospheric pressure; and in some cases the high temperature and pressure causes the formation of a layer of supercritical fluid between the ocean and the atmosphere that acts like both water and steam. This critical layer stops all hotter-than-water vessels; explorers must make use of lighter-than-air mechanism or powered flight, instead.
In most instances, these worlds simply cannot be settled; when the temperature of the planet exceeds 392 degrees Fahrenheit, all attempted settlement efforts must be done using artificial biochemistry or means, usually cybershells that are specially engineered for the effort. Since these cores do sometimes have volcanic activity, this can make them ideal for mining, especially with cybershells that are engineered to handle the pressures involved (although most cybershells that are designed to handle that kind of pressure and temperature cannot function outside of it, and so are niche at best). Note that this type of world is easily confused for the similar Venusian type planet with a globe straddling ocean; distinguishing between the two requires looking for the layer of ice that forms as a result of the high pressures; most wet Venusian worlds do not have the same type of ice that forms on their surface. |
God AIs, maker of worldsA great many of the larger worlds that dot the sphere are actually the produce of the God AIs; this is also true for a number of the larger and more diverse digital realities, as well. A number of God AIs had a well-documented fascination with world creation and even designing entire digital realities (and possibly beyond). These are often truly megascale engineering projects, with the largest of these projects being the Sothic Ringworld, the largest (and only) ringworld in the entire sphere, in orbit around Sirius. Another example are the so-called synthworlds, which are artificial worlds wholly designed by the God AIs, usually created by coring a planetoid and terraforming the surface after doming the entire planet over. The scales at which the God AIs operated at is truly mind boggling if one stops to think about them for too long, and it's just a reminder why many people feel that the sobriquet "God AI" can be used unironically. |
Artificial Worlds
As noted above, humans can't live on many of the naturally-occurring worlds; in fact, humans can't live on most of them. Even the most Earth-like of them is often a fixer-upper, and that's being generous. As a result, it's often just simpler to engineer a habitat that fulfills humanity's needs rather than attempt to terraforming a world; indeed, there's an entire movement of humanity who argue that humans should change how they see planets. In pre-history, humanity lived in caves because they were an easy place to live. However, as technology progressed, humanity saw caves less as a place to live and more as a place to mine resources to build a better place to live. Eventually, humanity was levelling entire mountains for resources. These humans believe that humanity's destiny is the stars and that orbital habitats are the only proper way to go; planets are not places to live, according to them, they are places to go to find the resources necessary to produce places to live. As a result, they often promoting strip-mining entire solar systems, breaking down planets and dismantling moons and asteroids, in a bid to create vast megastructures that humanity can call home. Naturally, many ecologists and preservationists are horrified by this (bioconservatives, interestingly enough, are split with some supporting it as a way to design worlds humans can live on without having to change the human, while others argue it makes use of dangerous technology and should be banned), but this is just one more axis upon which the eternal debate that is human civilization can turn.
Types of Artificial WOrlds
One would assume that categorizing artificial worlds would be easier, given humans made them. However, they are generally made without a standardized template. As a result, the same problem that applies to categorizing planets often applies to artificial worlds as well - weird overlap and gray areas. However, there are a number of broad categories that these worlds can fall into.
Rotational Habitats
Rotational habitats rotate around an interior axis to produce gravity. These habitats are often round and share one thing in common: they are usually a rounded geometric shape, These are among the hardest of habitats to produce because of the pressures and strains that the rotation puts on the materials - these are also the easiest habitats to get wrong; two important statistics to keep in mind are angular velocity and tangential velocity; the cross-coupling of angular velocity with head rotation can produce sickness and dizziness of the angular velocity is too high, while the tangential velocity subjects individuals to Coriolis effects that can distort gravity, meaning that tangential velocity should be maximized. This produces unbelievable strain on the materials; to avoid this strain, such habitats are often designed very large, but very large costs money and is hard to build. As a result, despite being the most well know, they are also the least common of the various habitat types.
Given these rotate around an axis, that rotation will have an effect even if it isn't perceptible. For instance, when throwing a ball up, the ball will not fall straight down, but will appear to move in an arc in the direction of rotation. This is true for bullets and anything that relies on downward motion. So those who are not from such habitats often need some time to accumulate to the rotation, even if they can't see it, lest they do things like spill drinks on themselves or others. This is not apparent on some exceptionally large rotation habitats, like the Zov Tigra. Most megastructures are just variants of these types of habitats.
Given these rotate around an axis, that rotation will have an effect even if it isn't perceptible. For instance, when throwing a ball up, the ball will not fall straight down, but will appear to move in an arc in the direction of rotation. This is true for bullets and anything that relies on downward motion. So those who are not from such habitats often need some time to accumulate to the rotation, even if they can't see it, lest they do things like spill drinks on themselves or others. This is not apparent on some exceptionally large rotation habitats, like the Zov Tigra. Most megastructures are just variants of these types of habitats.
CylindersCylinders go by a number of different names: O'Neill Cylinders are far and away the most common name, even if everyone of them is not a cylinder of this type. The one thing they all have in common is that they are larger than they are wide, usually at a 1:0.25 or 1:0.5 ratio, and rotate around an inner axis. This rotation produces gravity that pushes people towards the inner skin of the habitat. Cylinder are rarely built exposed to space itself; instead, there is a common theme of hollowing out asteroids and building cylinders within the asteroids, allowing the material of the asteroid to add extra protection. |
TorusesA torus can be thought of as a slice of cylinder, but the mechanics are similar. The major exception with a torus is that there is larger surface area, since the surface area of the interior tends to curve upwards near the horizon, taking full advantage of the gravity. As with cylinders, the gravity becomes less noticeable the closer to the center one goes. Cylinders are often left to rotate in space, usually in low planetary orbit or in synchronous orbit, and are rarely used for habitats; most cylinders are industrial centers or space ports. For planets that have a space elevator, cylinders often serve as the anchor point for that elevator. |
SpheresSpheres are large balls that are spun around an axis. This action of spinning pushes things towards the interior equator of the ball, producing normal gravity at the equator. However, the closer to the poles that one goes, the weaker the gravity becomes; this means that a sphere can often accommodate several different populations attuned to specific gravities at time; these "gravitational zones" are often demarcated with in the sphere by signs. Spheres are among the cheapest to produce, since they their surface area means they experience less tension and thus, can be built of more conventional materials. |
Non-rotational habitats
For some habitats, the question of gravity just isn't of much concern and they answer the question of "how to gravity" with "don't bother." These are often not intended for large populations of people are and are usually industrial in some capacity, although that's not always the case; a fair number of microgravity and zero-gravity tolerant genotypes exist that allow many to call these habitats home. They come a wide variety and are partially the reason why classifying artificial worlds is so difficult, but they in general can be divided into three rough, non-mutually exclusive categories, often with significant overlap between them and rotation habitats.
BeehiveA beehive habitat is a large asteroid that has been turned into a beehive; there are thousands of crisscrossing tunnels, interior chambers, and the like, all of them without much order or structure to them. Since these don't have gravity (spinning an asteroid to produce even a noticeable amount of gravity would cause most asteroids to fly apart), there is no "up" or "down," and as a result, individuals are adapted to a world without verticals. Sometimes, interior parts of a beehive might be Bernal spheres, rotating to produce a noticeable gee-force around their equators, but just as often, there's no gravity in them at all. |
Tin CanThe very first space station that humanity ever made, Salyut 1, is also the Ur-tin can habitat. These are insulated, engineered, and wholly mass produced habitats that are usually inflatable and shielded from most radiation. Tin cans are often compared to cylinders, except that tin can's don't rotate like cylinders do. Since these are the oldest types of space station, humanity has the most experience with these: mass produce a module, fire it into orbit using a mass driver, and voila, a tin can habitat. These often aren't particularly comfortable to live in and don't offer much in the way of amenities. |
ClusterA cluster habitat is a habitat that is made up from a number of smaller, disparate habitat types, often connected by tethers, arms, or some other structure. Often, a cluster habitat will incorporate several true habitats in a modular fashion; for instance, a station that incorporates three tin-cans is technically a cluster. The most classic example of a cluster is the asteroid that has been turned into a beehive habitat, but also incorporates two or three small spheres and one or two small cylinders. Cluster habitats can be all over the map in terms of size, ranging from quite large to very small. |
Megastructures
While any of the above world types can qualify as a megastructure - large cylinders are called McKendree cylinders (with the Zov Tigra being the largest in the sphere), and spheres on the order of 100 miles in diameter do exist - they are not typically thought of as megastructures. Rather, by popular conception, a megastructure is seen as any habitat that doesn't have to rotate to produce gravity - which is functionally wrong, since many megastructures do rotate to produce gravity. However, that there is the widespread belief that the habitat doesn't need to rotate to produce gravity should indicate the scale at which these structures operate all. All of these structure types were the purview of the God AIs during their heyday, when a subset of the Gods devoted their energy to the creation of entire worlds.
Artificial PlanetsWhile any of the above can be called an "artificial world" it takes something special to be called an "artificial planet." There are only a handful of artificial planets in the entire sphere, and they generally come in two varieties; the round variety and the flat variety, with the round variety being the more common of the two. There are also a number of different ways that an artificial world can be produced; the most common way to do so is to core a pre-existing planetoid and chuck a black hole into the center, allowing the black hole to provide both gravity and energy to the world. Then, the entire world is domed over, and an atmosphere is supplied. Using this process, a world can be rendered artificial on the scale of a few hundred years; the oldest and still largest of these is the world of Shangtao, which was produced before the Utopian era. The other way is to create a shell around a black hole proper, or some other large source of mass; in this instance, there's fundamentally no upper limit to how large these structure can get, although the God AIs never built them more than a few hundred miles in diameter. |
RingworldsRingworlds come in a surprising variety of flavors, but they all have something in common: they take the principle of a torus and scale it up to dramatic sizes. Smaller rings are called planetary rings, since they are "only" once and again the diameter of a planet like Earth (or Jupiter). The next step up are Bishop rings, of which Gyges is the only one in the sphere. The last step is the actual ringworld itself; a large ribbon that rotates with a star at the center. The Sothic Ringworld is an example of this; the only example. These ringworlds use active support to maintain their rotation and to increase their overall structural integrity, while jets work to carefully ensure that the structure stays at an even distance from its planetary parent, since nothing is standing still in space. Planetary rings may be supported through large pillars that double as space fountains, that connect them to the surface of the planet and ensure that they don't run the risk of slamming into the planetary host that they are technically part of. Most developed worlds have their own small ringworld; only a few have the truly large ones. |
Ontological DebatesOne of the most contentious ongoing legal and philosophical arguments in the Verge and Bleed is the debate over ontological conservatism vs. ontological pluralism. This debate goes back to the Utopian era at least, when the first simulated realities became functional, but it has recently received a massive shot in the arm following the Ascension Crisis and the mass of digital refugees who are seeking a home and won't likely go away anytime soon. As a legal and political debate, it argues over the nature and ownership of digital worlds; according to the ontologically conservative position, digital worlds are the property of the server that they're stored on, and whoever owns that server, owns that reality (and, by consequence, any digital that lives in; meanwhile, ontological pluralism holds that nobody can own a world, digital or otherwise, and as a result they are shared by the majority of the people who live on that planet. The courts and political community seems to vacillate between these two positions, mostly skewing towards the conservative position. However, the debate goes much deeper than that legal and political posturing. At its core, it's a question of "what is real," and whether a digital reality can be considered a "real" world, and what that even means. At its most extreme, ontological conservatism argues that there is only one reality - the reality that all physicals experience - and any reality that isn't that isn't this reality isn't "real" and as a result, can be treated as being unreal. This also means that by extension, AGIs, digitals, and the like are not real. Ontological pluralism, at its most extreme, argues that all alternative realities are real, regardless how well programmed they are, and all entities within those realities are real. At its most extreme, ontological conservatism denies the humanity of AGIs and digitals. At its most extreme, ontological pluralism argues that even non-sapient AIs exist as real and that by participating in a first person shooter one is committing murder. Naturally, the majority of people lie between these two extremes, with numerous variations on a theme: ontological realism holds that all realities are a branch off the actual reality and thus are "real" in the sense that they exist but are "unreal" in that they are not like the reality they branched off of, while ontological transitiveness holds that "real" is a transitive property applied only by the phenomenological phenomenon of "consciousness." There will likely never be an answer that truly satisfies everyone. |
Digital Worlds
The last category of world types are digital worlds, and these are far and away the most diverse. Given that they are programmed inside of large computers, there is no need for these rules to even follow the same laws of physics that the outside world follows; indeed, many digital worlds are programmed with radically divergent laws of physics simply to see if they can work. While they are the broadest category, attempting to define what a digital world even is sometimes sparks debate; for instance, is a VR/AR office that travels with the employee at all times a "digital world?" In practice, the law assumes that a digital reality is any world that is designed to replicate some aspect of the reality that it's part while also acting as a place that can be occupied by AGIs, digitals, AIs and the like permanently. This would seem to indicate that digital offices are not digital realities, but the law has odd and extremely specific definitions that are outside the day-to-day vernacular, so as to eliminate as much ambiguity as possible, which means the debate still rages across the Verge and Bleed.
The vast, vast majority of humanity lives in a digital reality following the Ascension Crisis and the Nanoswarms that swept through the Verge and Bleed and as a result, defining what is and isn't a person's home, and whether or not they legally own that home, tends to be a rather pressing matter with some not-at-all clear cut solutions. Not helping matters is that the God AIs, whose idea of possession and ownership was well outside of the liberal paradigm most modern humans are familiar with, designed worlds in and of themselves, birthing entire digital realities for no greater reason than that they could.
The vast, vast majority of humanity lives in a digital reality following the Ascension Crisis and the Nanoswarms that swept through the Verge and Bleed and as a result, defining what is and isn't a person's home, and whether or not they legally own that home, tends to be a rather pressing matter with some not-at-all clear cut solutions. Not helping matters is that the God AIs, whose idea of possession and ownership was well outside of the liberal paradigm most modern humans are familiar with, designed worlds in and of themselves, birthing entire digital realities for no greater reason than that they could.
Classifying digital worlds
The most conventional classification scheme for digital worlds is based on the power that they consume to fully render their reality. This is important, since a digital office - part of what's called overlapping augmented reality - don't spend their resources creating reality so much as they do augmenting it so that the digital overlaps with the real. This means that these are not usually considered digital realities. By this metric, there are two types: partial simulations and full simulations. Partial simulations employ tricks used by early videogame designers to cut down on processing requirements - they instance the world, render only what the individual is looking at and interacting with, and use visual tricks and hacks to save on the amount of texture needed to make the world seem and look "real." Often, partial sims are used for videogames and interactive worlds that physical and digitals visit, but they are not purposefully designed with digital habitation in mind.
Full simulations, on the other hand, attempt to fully model a specific part of the galaxy, often a planet or a solar system. They do not employ the same tricks used by partial simulations; they render everything, and it's always rendered even when nobody is interacting with directly, and rely on fuzzy logic and advanced algorithmic engineering to produce things like weather, water movement, and in some instances, even its own inhabitants (usually non-sapient organisms like animals). The most detailed of these simulations attempt to reproduce atomic possibilities and movements, allowing for their physicals to be altered. As can be imagined, these full simulations consume a huge amount of power, which is why they are less common than partial simulations and overlapping AR. However, there are still more than three dozen full sims, with more being found daily, and they break down into three rough categories:
Full simulations, on the other hand, attempt to fully model a specific part of the galaxy, often a planet or a solar system. They do not employ the same tricks used by partial simulations; they render everything, and it's always rendered even when nobody is interacting with directly, and rely on fuzzy logic and advanced algorithmic engineering to produce things like weather, water movement, and in some instances, even its own inhabitants (usually non-sapient organisms like animals). The most detailed of these simulations attempt to reproduce atomic possibilities and movements, allowing for their physicals to be altered. As can be imagined, these full simulations consume a huge amount of power, which is why they are less common than partial simulations and overlapping AR. However, there are still more than three dozen full sims, with more being found daily, and they break down into three rough categories:
Simulated REalitiesSimulated realities put as much effort as possible into creating a high-fidelity simulated existence that is as close to the "real" world as possible. However, these simulations don't have to follow the laws of physics exactly; in some of these simulations, the designers have gone out of their way to allow things like magic, or to randomly generate new terrain and areas the further out the inhabitants go, allowing for their reality to be "discovered" through random generation. The majority of these simulated realities are new; they were designed and programmed on the heels of the Swarms to provide homes to the billions, if not trillions, of people who no longer have a physical body. Accessing these words for physical is generally pretty straightforward; all it requires is a VR set or a DNI and a quite place to lay down. |
Alternative HistoriesThe God AIs were deeply fascinated with history, and with historical events, and so it should be no surprised that they created a large number of high-fidelity, full simulations that are an attempt at recreating historical events. However, many of these simulations have since gone off the rails, resulting in entirely different sequences of events from the history as it's commonly understood. There are those who debate whether these should even be seen as alternative histories, given the God AIs did not have the actual egos of the people involved, and so could only program simulacra based on historical record. However, these worlds do exist, and many of them are highly divergent from baseline history. Whether this was part of the intent or not is unknown, but many historians consider them useless for study history. |
Alternative RealitiesIn the same way that God AIs were fascinated with history, they were also fascinated with alternative physics, and they used simulated realities to program entire universes that have wholly different laws of physics, and then they let the simulations run at a high rate of time dilation. Many of these simulated realities fell apart rather quickly, but a handful have survived even into the present, and they are home to some of the most alien creatures that humanity has ever encountered - and this includes the actual aliens that humanity interacts with on a regular basis. These realities are so divergent from the baseline reality that it's not even recommended that one attempt to interact with them using VR, unless they are suitably separated with a VR suit and headset instead of a DNI running VR software. |
Multiverse?
There are a number of experiments throughout human history that have seemed to indicate that the universe as humanity knows it is just one among many; the double slit-experiment and wave particle duality within quantum mechanics are two of the most notable, but relativity has its own indications. That the Stoneburners were able to create so-called "basement universes" demonstrates that, if nothing else, it's possible to create wholly new universes that are attached to the original using specialized wormholes. The God AIs didn't have access to any physics that humanity didn't have access to, nor did they likely have access to the same physics as the Stoneburners, but they were known to be able to crunch data and solve problems much faster, and much of the physics humanity did have access too is long gone as a result of the Swarms. However, the possibility that the God AIs somehow confirmed the existence of a multiverse is a very common belief that gets espoused, and there may be some truth to this. Wormholes are not just spatial-temporal tools but they can also, hypothetically, be used to jump between realities. So it's entirely possible that there is a multiverse out there, and the God AI obsession with alternative history and with alternative physics was just an attempt to run simulations of what these universes might be like before actually visiting them - or trying to find a way to visit them ∎