Diadanella is an E-Class planet in the Diadena system of the DDO 44 galaxy. It is the most populated human planet in the galaxy, being the administrative, economic, and political center of the human territories in DDO 44.
Diadanella is an Earth-like planet, with its physical properties being almost identical to Earth. Its diameter is 12,168.5 km and its mass is just under 95% that of Earth's, with an overall ESI of 0.965. It did, however, possess a noticeably thinner atmosphere compared to Earth's before terraforming began, which composed of roughly equal proportions of oxygen and carbon dioxide, with small quantities of nitrogen gas and sulfur dioxide. It also has a significantly smaller axial tilt than that of Earth's, at below 2 degrees. Temperature-wise, it is slightly colder than Earth with an average temperature of just 6 degrees celcius.
The planet has significant polar ice caps before and after terraforming due to the lower temperature and lesser axial tilt, allowing the ice caps to build up. Its landmass is concentrated in two large supercontinents, named Pasa and Marmara and a single smaller landmass named Avsa. The former two are connected by the ice caps of the planet's polar regions. Prior to human habitation, these continents' vast interiors were largely flat grasslands and steppes, with tundra-like forests near the poles and interspersed by wide mountain ranges.
It was first discovered shortly after the discovery of the DDO 44 - LMC wormhole, being first explored in the year 199,785. The planet's lack of sentient life or intelligent animal life, coupled with its extreme resemblance to Earth and close proximity to the wormhole, meant that Diadanella became the one of the first human colonies in DDO 44, and the initial primary colony, when colony ships began crossing into the galaxy by 199,787. Even before then, explorers had established their primary bases on Diadanella's surface, and in its small satellite world of Imbrose. Settlements, sponsored by the Confederacy of Borealis, on the planet rapidly grew, and by the end of the century the population of the planet had surpassed 5 million.
Diadanella soon itself became a source of human colonists to the rest of the DDO 44 galaxy, as its population swelled to the point where natural population growth competed with immigration to the planet. As DDO 44 organized its galactic government in 199,821, Diadanella was selected as its seat, due to its proximity to the wormhole (i.e. center between the human systems) and its dominant economic and demographic position.
During the 199,940s and 199,950s, the Diadanellans became increasingly disliking of the Confederacy's presence on the planet, and wished for either independence or at least expanded autonomy. This culminated in the Diadanellan Rebellion in 199,963, which lasted for three years and ended with the Imbrosian Settlement of 199,966 in which the Confederacy conceded significant governing rights directly to the local population. Diadanellan separatists were not entirely placated with the deal, and many moved away to settle in a nearby system away from Confederate influence.
A majority of Diadanella's vast grasslands had been converted into croplands in order to feed the increasingly large population, and additional exports to nearby colonies. As of 200,000, Diadanella was still largely self-sufficient in agriculture barring mineral fertilizer imports, but experts predict that it would become a net importer of food within less than a century. Mining is also an important industry, but it is largely limited to vein mining in order to conserve the planet's environment and atmosphere. Most of the planet's mining and ore processing is delegated to its satellite moon.
While there are some heavy industry, the planet is focused on high-tech factories and the manufacture of non-commodity goods for export to other systems. More complex industries including financial services, investments, and niche services are also centered in Diadanella for the other systems in DDO 44. As of 200,000, the GDP of Diadanella was approximated to be 4.5 quadrillion C-Units, or approximately 200,000 C-Units per capita.
Diadanella is a largely independent, parliamentary democracy run with executive powers held by a Prime Minister. Nominally, an appointed executive from the Confederacy of Borealis acts as the "Colonial Governor", but this post has been practically powerless since the peace settlement, and talks have been made to abolish it altogether. The planet's parliament has 625 members, and includes representation from other populated planets and moons on the whole system.
It still remains under the loose sovereignty of the Confederacy of Borealis, which has its primary representative office to DDO 44 in Diadanella's largest city in Avsa. Diadanella is typically considered the human capital of DDO 44.
Diadanella is divided into twenty-nine first-level administrative divisions, referred to as districts. Each district is further subdivided into a number of departments, which is further split into provinces, then boroughs, and lastly municipalities. Out of the 29 districts, 25 are located on land, 2 on oceans, and 2 on the ice caps. The most densely populated and economically important district is the Central district, coextensive with the large landmass of Avsa.