This category contains the known cosmology concerning the plane on which Austraeoh takes place.
Origin of the WorldEdit
The world as ponies know it is actually the broken segment of a ring which was part of a large superstructure called Urohringr, which was itself an inner ring forming part of an even larger cosmic structure. It was inhabited by ancient pegasi, as well as "guests" from other words (these are implied to be wyverns, harpies, and seaponies). Both sides of the structure were designed to be habitable.
Following the Sundering, the segments of Urohringr drifted in chaotic space for an unknown amount of time, during which the pegasi built structures to attempt to observe and communicate with their separated brethren in the cosmos. Eventually, they were discovered by the Alicorns who were traveling from the Plains of Harmony to foster and to protect life in the cosmos. According to Chrysalis, this group numbered in the thousands. They decided to create the Sun and Moon to regulate life, and establish the Firmaments to separate the world from the cosmic chaos. Essentially, the world is in a little "bubble" that is protected from the chaos. This cosmological model is likely to be shared with that of Background Pony, in which the physical world is separated from the universe by a firmament of oblivion and nothingness which cancels out energies from either side.
Because the alicorns did not possess enough energy to lighten both halves of the world, they decided to divide the world into a light side and a dark side - one to be blessed by their sun and moon, the other to remain exposed to chaos and darkness, "...separated merely by the corners of the earth, where they pierce the fabric of the firmaments.” This was deemed necessary in order for the world to survive. The Sun and Moon are nothing more than "...bodies of luminous mana that the alicorns brought to this plane."
The Light Side Edit
What we call the "light side" of the earth is really just the convex side of the broken ring segment. This side was favored by the lost pegasi because it allowed a wider view of the cosmic expanse, as they tried desperately to regain contact with their lost brethren. The alicorns also seemed to favor this side because it simulated the curve of a globe. It contains natural topography and looks just about how you'd expect the world to look.
These are ancient machines buried deep underground, apparently only accessible to specially chosen pegasi. These machines control the features on the surface (Darkstinian obelisk, Blue Shelf terraforming as examples).
It is unknown whether one can travel between the light and dark side via the machine layer, partially because it is not understood how gravity is generated.
The Dark SideEdit
It is apparent from the symbol given in Urohringr that in addition to the 12 segments of the ring, there were also 12 (or possibly more) "Sentinels". Queen Chrysalis says that Stratopolis is one of these stations. Their exact purpose is unknown, but they are assumed to be some sort of control system.