Manifold Sky
The Manifold Sky, or simply Manifold, is an enclosed universe with an unusual, non-euclidean geometry. The whole Manifold is a penteract - a five-dimensional cube - with all five spacial dimensions measuring roughly 50 miles in length. The Manifold is part of the Celestial System which is, in turn, embedded in the Celestial Realms.
Geography
The space within the Manifold Sky is actually a series of hollow three-dimensional cubes, all of which are situated coterminously with other cubes via the commissures to form tesseracts (four-dimensional cubes these tesseracts are, in turn, coterminous with other tesseracts via the inflection layers to form a penteract (five-dimensional cube). The Manifold contains ten tesseracts subdivided into a total of 40 cubes, with each cube subdivided into two layers, each layer being "adjacent" to a different tesseract while still representing a part of the same cube.
Gravity has a much shorter effective range within Manifold Sky. Within each three-dimensional cube, the direction of gravity points towards the nearest face; in areas close to the junction of two or more faces (i.e. the vertices of the cube), the vector of gravity is the sum of those of the adjacent spaces (i.e. "down" points towards the corner near the vertices), meaning that mountain ridges tend to form along the edges and peaks near the vertices.
In the center of each face of a cube layer, a large fissure in the ground allows access to adjacent cube layers within the same tesseract. These terrain features are known as commissures. Conversely, as a traveler approaches the geometric "center" of a given cube, directly between the layers of the cube, they approach an inflection layer; once crossed, the traveler finds themselves descending into a cube layer within a different tesseract, with the cube layer they just left receding into the "center" of this new cube layer as they travel away from it.
Successfully traversing the Manifold is tricky even with modern dieseltech technology. The Navigator's Guild has achieved near-universal presence in societies under the Manifold Sky by providing the knowledge required to safely travel between tesseracts and by suppressing the development of alternatives to their services. For this reason, many consider the Guild to secretly be the true rulers of the Manifold Sky, though the ruling classes of the many nations who regularly parley with them would never admit that out loud.
Ecosystem
Different cubes withn the Manifold have different environmental conditions as a result of a variety of geological and cosmological factors tied to the tesseract in which they are embedded. Generally, tesseracts on opposite sids of the penterract have environmental conditions that are biased in the opposite direction from one another:
The Medial Tesseract - as well as most cubes - host biochemical systems based on right-handed amino acids, while those of the Distal Tesseract are based on left-handed amino acids. This difference in chirality means that, while wildlife from one region can threaten the other, the food is mutually inedible and things like diseases are not mutually transmissible. The atmospheric chemistry of the Distal Tesseract is also such that much of the visible spectrum of daylight is filtered, meaning that the terrain is lit most strongly in the ultraviolet and infrared rather than in colors that humans can see.
The Western Tesseract is comparatively oceanic, in part, because the reducing environment of the Eastern Tesseract - particularly the Eiquereus Craglands - has scavenged much of the asmospheric moisture from cubes in or near it.
The Rostral Tesseract may be more 'equatorial' in terms of the Manifold's strange orbit around Selevati, making its warmth starkly contrast with the chilly winds and longer nights of the Caudal Tesseract.
The mountainous Ventral Tesseract is highly geologically active in comparison to the flat, geologically stable Dorsal Tesseract.
The Northern Tesseract and Southern Tesseract, though they appear similar in their wide diversity of alien-looking life and relative paucity of sentient habitation, represent opposite poles of the Manifold's magnetic field. They also experience opposite electrostatic charge as a result of Selevatiar radiation, the flux peaking during the solstice 'radiation storm' season.
Ecosystem Cycles
Guild Compass Rose by BCGR_Wurth
Localized Phenomena
Light emerges from every place at once from the hidden additional spatial dimensions, likely an extradimensional star known as Selevati. The directionality of shadows and the intensity of light coming down from the inflection layers is a result of relatively larger volume of space above the ground wherein light can emerge. Light generally does not escape once it emerges, and the question of how the energy provided by this light escapes the Manifold once it has been absorbed by the terrain is an ongoing mystery.
Fauna & Flora
The Manifold plays host to a wide variety of non-sentient life, akin to the biological diversity found in most habitable environments one could concieve. It is unique in that it has four different sentient species who live concurrently with one another, as well as several others who didn't survive to modern times. Living sophonts include the Rostrans, verdials, humans, and ovinex. Extinct sophonts include the lepidosians, feldeans, and perhaps a few more whose legacies have yet to be uncovered by archaeology.
History
Sentient life emerged in the Manifold in several places at once at around 10,000 years ago in an event so curiously simultaneous that it inspired the creation of the Manifold Standard Calendar by which almost all such species now measure time. This emergence seems likely to have been the result of unnatural effects - most likely the intervention of some unknown, external intelligence - given that all these species share a similar mythology concerning what life might have been like before this emergence. All species have vague ancestral recollections of living on spherical worlds before being trapped beneath the Manifold Sky for unspecified 'transgressions.' Whether the so-called Curved Time is an inescapable chapter of a dark past or a quasi-spiritual place that one can aspire to return to is generally considered a matter of religious, rather than scientific, debate.
Maps
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The Manifold At A Glance
This is a generalized map of the Manifold Sky, with cubes and tesseracts shown based on their relative connections to one another. Tesseract labels are based on Navigator's Guild nomenclature. Cube topology and geopolitical boundaries are excluded. Additional layers show various points of interest and the comfortable habitatats of the various sentient species within the Manifold. Note that the compass rose shows the progression of day and night through the tesseracts, as well as the relative position of magnetic north (green arrow).
Alternative Name(s)
Manifold
Type
Multiverse
Location under
Included Locations
Owning Organization
Contested By
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Related Myths
I SWEAR I HAVEN'T!