New Aedun is the capitol world of the Imperium of Sidhae. One of the most populous of the Imperium's core worlds, it is home to over 100 billion residents, most of them crowded in massive clusters of hive-cities whose spires reach well into stratosphere.
Settled around 2083, New Aedun was colonized and built up for the purpose of relocating the Imperial capital and bureaucracy from it's original seat on the tropical world of Aedun. Not wanting to destroy the pristine native environment of Aedun that had proved the saving grace of their race, Sidhae would relocate their capital to the arid New Aedun, declaring old Aedun a wildlife reserve and a historical monument off-limits to most visitation and development. New Aedun was picked for having an atmosphere, surface gravity and temperature roughly equivalent to that of Terra, but fairly little native life, the arid wastelands of Aedun's continents consequently made for a perfect settlement site.
New Aedun was developed very rapidly in the following century, the population skyrocketing as the progenitories worked in overdrive to populate the planet and swarms of robots worked to prepare living space for them.
It was during this time that the colossal 30-kilometer Imperial Spire was constructed. A massive arcology complex - a "hive" - designed expressly to house the Imperial government and massive bureaucracy, this elaborate complex is still the envy of other galactic powers. The Imperial Spire is the tallest structure on planet, the numerous space elevators leading to New Aedun's massive orbital rings excluded, and is easily visible from space. The top of the Spire houses the Empress's personal quarters, numberless other prominent officials residing in the lower levels. It is also here that the General Assembly meets regularly to discuss political matters and pass legislation, the Assembly Hall being larger than most sports stadiums and capable of accomodating over 100 thousand attendants. Similar to other hive-cities, the Imperial Spire's subterranean levels likewise reach many miles deep, almost to the bottom of the planetary crust, and house the hive-city's industries, utilities and power sources.
Due to it's central location and heavy defenses, New Aedun has never suffered extensive military action or abandonment like many other Imperial worlds. Even during the Second Pilgrimage, New Aedun wasn't completely evacuated, and was quickly resettled when it became clear that neither the humans nor the Skargh would push further into the abandoned realms of the Old Imperium, believing them to be completely abandoned and expecting to find nothing more than ruins (along with being pre-occupied with fighting each other). The only major military action that New Aedun has seen was the Seven-day Siege during the Sidh Civil war, when the Traitor Clan fleets besieged the capitol world and very nearly succeeded in their assault on the Spire, but were successfuly repelled when several Imperial Guard legions and their battlefleets arrived to relieve the beleaguered world. Damage to the planet and its infrastructure was minimal, since both the Traitors and the Loyalists intended to use it as their power base and hence made every effort to minimize collateral damage.
Because of this long history of uninterrupted habitation and minimal war damage, New Aedun is consequently more heavily built up and developed than most other Imperial worlds, even by core world standards. Effectively an ecumenopolis, nearly every suitable area on New Aedun's surface is urbanized, covered in strata of urban development that are sometimes many miles thick. Hundreds of massive hive clusters dot the landscape, with much of the surface in between covered with less massive urban areas. City-scapes extend many miles below the surface and beneath New Aedun's oceans as well. For a lack of space, many areas even have "floating hives", massive urban blocks the size of small cities held perpetually aloft by powerful grav repulsors, these technological marvels being bound to leave a profound impression to any foreign visitor. Consequently, most residents of New Aedun (or any other hive world) can live out their entire lives without ever seeing the sky of their homeworld or touching it's actual surface.
Although Sidhae make every effort to keep their worlds self-sufficient, massive multi-story hydro-farms and biotech plants spanning country-sized stretches of land growing food for billions, New Aedun is still dependent strongly on imports for subsistence. Being the Imperium's center of commerce and finance, this isn't much of a problem for the time being.
One of New Aedun's main industries is shipbuilding, as is reflected by it's two massive orbital rings gradually built up over the centuries by connecting orbital facilities. Owing to a very dense and mineral-rich asteroid belt within the system, New Aedunites would take to asteroid mining early on, saving them the expense and difficulty of extracting materials from the planet and raising them to orbit. As mining ships towed metal-rich asteroids into orbit for easy extraction, the depleted rock husks and the facilities based around them accumulated over time, eventually being connected into a single uninterrupted ring that serves as a massive orbital habitat housing docks, shipyards, warehouses, mineral refineries and everything else typically found in major spaceports. Significant portions of the rings are dedicated to housing and maintaining the Imperial Guard's vast naval armadas, and New Aedun shipyards are one of the few sites in the Imperium capable of constructing and maintaining dreadnought-class vessels. Over 50 thousand vessels dock in the New Aedun rings every day, shipping materials and goods from all over the Imperium.
Because of this massive population and industrial development, pollution is rife on New Aedun, but is rarely noticed due to the self-contained nature of hive-cities. Although the authorities are doing their best to clean up the environment, with such build-up whose complexity goes beyond the capacity of organic mind, keeping track of every toxic spill and sewage leak is next to impossible, many areas especially in the lower hives and outside them consequently ending up badly contaminated.
New Aedun's only moon, Chronos, is essentially a miniature forge-world by virtue of being very rich in metal ores, and serves as one of the primary sources of metals to supply New Aedun's shipyards and industries. The areas of Chronos not being actively mined house massive foundries and factory complexes. A significant portion of these are dedicated to supplying the Imperial Guard with armaments. Chronos also houses colossal planetary defense batteries meant to augment New Aedun's own formidable defenses that include a recently-installed prototype planetary shield theoretically capable of shielding the entire world even against dreadnought-class weaponry. Despite being smaller than Earth's Moon by a considerable margin, Chronos is considerably denser because of it's great metal content, it's surface gravity approaching that of Mars. The tidal forces on New Aedun aren't significantly greater than on Earth though, mainly because of the greater orbital distance of Chronos.