Erdath

Erdath is the third planet of the Holias System in the Vernarca Nebula, of the Ervo Sector of the Silky Way galaxy. It is a temperate, if cool, world with life covering much of its surface. In the distant past, it was little more than a colony of the robotic Edrons before their destruction in war, but today it serves as the homeworld of the Lrenn, capital of the Erdathian Federal Republic, and a major world of the Vernarcan Federation.

Erdath was named so by the ancient Lrenn, after the god of the dust then believed to rule all. Its surface is teeming with life of all sizes, from bacteria to great whales, from the depths of the ocean to the most dizzying of mountain peaks. As the homeworld of the Lrenn, it has served a vitally important role in the history of the Vernarcan Federation, as the capital of the Erdathian Federal Republic, one of its founding members.

History

Formation

Erdath formed over five billion years ago, in the nascent Holias System in an ancient seed cluster which has since ceased to function as such. The planet was created from a synestia, which formed from the impacts of multiple protoplanets which orbited between 0.6 and 1.5 AU from Holias. This process concentrated the mass in this area within the new planet Erdath's sphere of influence, and created an impressive debris disk even after the planet coalesced properly.

From this debris disk, multiple large moons were created of various sizes. The largest of these initial moons is believed to have been Verto, with the others either being ejected from the system, crashing into each other to create Lirtso, or being torn apart into the Erdathian ring system. Other impacts would occur, bringing volatile compounds from the outer solar system including the water that now fills its oceans.

Evolution of Life

Edronian Era

Rise of the Lrenn

Colonization of Space

Erdathian Domain

Glorious Revolution and the Federal Republic

Federation Era

Modern Times and the War of the Broken Bow

Physical Characteristics

Erdath is among the largest worlds to support sapient life within the Ervo Sector. With a mass of almost three standard terrestrial masses, its surface gravity is high enough to make living there uncomfortable for many species of the Vernarcan Federation. Its high mass leads to a substantial amount of active volcanism across its surface, as well as highly active plate tectonics. Within the Holias System, Erdath is the largest terrestrial planet by far, with both Lovos and Eloraz being less massive than Teralla.

Like most terrestrial worlds, Erdath's surface is made up of silicate compounds, around 40 kilometers thick on average. Most of its surface at over two thirds is covered in ocean water, and in the distant past it may have completely submerged the planet. A great number of freshwater lake and river systems exist as well, hydrologically separated from the salty oceans.

By Terallan standards, Erdath is deep in a seemingly permanent ice age, with nearly a fifth of the planet covered by its polar caps. This causes grievous erosive processes to take place over its non-equatorial landmasses.

Erdath's interior structure is defined by several layers, separated by differences in chemical or physical makeup. The outermost layer is made up of a silicate crust, broken into plates and floating about over the viscous but technically liquid mantle. Beneath this can be found a large iron-nickel core, with a large molten outer layer which generates the planet's magnetic field surrounding a pressure-solidified center heated to temperature hotter than the surface of the sun. The magnetic field the core generates is among the most powerful in the system, only matched by the gas giants whose fields are generated by metallic hydrogen, and protects the entire Erdathian moon system from Holias' solar wind.

Orbit and Rotation

Erdath orbits its host star, Holias, with an orbital period of 383 days and an orbital radius of around 1.06 AU within its star's habitable zone. This makes Erdath the third planet within the Holias System, orbiting well beyond Lovos and beneath the orbit of the Senith Belt near Vulus. The planet's lagrange points are occupied by the Tavi Group of asteroids, which together made up the first colonies of the Lrenn beyond the planet's sphere of influence.

Erdath rotates once every 1.25 days, with a minimal axial tilt of just 2.35º. This means that Erdath has functionally no seasons, with its "arctic circle" being almost right on top of the poles.

Atmosphere

The only world in the Holias System to possess an oxygenated and hydrated atmosphere with no artificial intervention, Erdath is a very special place. At sea level, Erdath's atmospheric pressure is approximately 3.84 atm or 389.09 kpa, with a scale height of just over five kilometers. This atmosphere like most terrestrial worlds is composed primarily of nitrogen, oxygen, and argon, with half a percent worth of carbon dioxide throwing a wrench in the works. Water vapor's fractional presence is highly variable, creating cloud coverage over around 1/3 of Erdath's surface.

Like most worlds with any semblance of life, this life has greatly affected Erdath's atmosphere. Photosynthesis' introduction led to the disappearance of the primordial volcanic atmosphere, replacing it with the modern oxygen/nitrogen mix, which allowed aerobic organisms to come into being. This also resulted in the creation of the ozone layer, which blocks Holias' ultraviolet radiation from hitting the surface and killing everyone.

The enormous amount of carbon dioxide in the Erdathian atmosphere also creates a substantial greenhouse effect, raising the average temperature to just above freezing by preventing infrared emissions from the surface from escaping into space. The planet's equilibrium temperature without this effect would have been -30º C, which would complex life massively harder than it already is.

Geography

Erdath's surface, with an average temperature just two degrees above freezing, is dominated by fjords, tundras, ragged mountains, and vast ice fields covering much of the seas. Due to Erdath's size, the planet has a highly active plate tectonics system, with plates smashing into each other and later pulling apart at such momentums as to push up vast mountains even under the planet's higher gravity. Over Erdath's five billion year history, most of the planet's land area has thus been affected, creating a very mountainous surface.

Erdath's surface is dominated by a single large supercontinent, Drovala, with the rest of the planet's land area broken up into a large number of subcontinents and island arcs. The poles are largely iced over, with permanent ice caps forming over 14% of the planet.

Climate

Erdath's climate is, as a rule, cold. While calling it "marginally habitable" is a bit of a stretch, it certainly isn't as superhabitable as a world like Teralla. With Holias' light adding up to 1310 W/m² of irradiance on average, its equatorial regions possess climates analogous to the boreal or subarctic regions found on Teralla.

The planet's strong greenhouse effect and thick atmosphere also means that its average temperature is more uniform, with temperature dropping off much more slowly as latitude increases. However, it still does decrease, and the far north and south are in a permanent deep freeze with large-scale ice caps, very little precipitation, and frozen oceans.

Surroundings

Due to its size, Erdath's sphere of influence is filled to the bring with a massive and great variety of objects, ranging from its twin large moons of Verto and Lirtso to the innumerable rocks making up the Erdathian ring system, to the few outer captured asteroids, to the vast number of artificial habitat stations which exist in its orbit. From afar, its ring system is the most visually striking set of objects within Erdath's sphere of influence, but its two moons add up to more mass in total.

Verto

The first of the major moons, Verto is a barren moon predominantly covered by craters with little geologic activity. Its ancient rocky surface is covered by a massive ecumenopolis, with a great population of almost a trillion people. Verto orbits Erdath once around every five days, which marks the length of an ancient Erdathian week.

Verto's massive colonization by the Lrenn early in the history of its space travel has vastly changed its surface, from a barren rock face to a massive globe-spanning city. This city is partially covered beneath an impressive set of domes, holding the artificial atmosphere in over the urban areas. Other parts of the city are situated entirely underground, dating back to the ancient subsurface colonies using the lunar regolith as radiation shielding.

Lirtso

The largest and outermost of the twin major moons of Erdath, Lirtso is a barren moon with a pale, dusty and cratered surface and seemingly little to recommend it from afar. Unlike Verto, it has a thin atmosphere, which does very little to warm its cold surface, and indeed parts of it are even covered in ice. However, beneath the surface can be found a cornucopia of resources, valuable to the early Lrenn and necessary to expand beyond their supermassive homeworld. While most of the easily accessible resources have been thoroughly exhausted in the modern day, the moon remains useful in another way as a great population center, similar to its smaller companion Verto.

Ring System

Erdath's space is visually dominated by a vast, dramatic ring system circling the planet, formed when the mysterious third moon of Erdath crossed beneath the roche limit due to gravitational interactions from Verto and Lirtso. After this, it was quickly torn to pieces, forming the majestic rings seen today. Due to their position within the Holias System, the rings are composed primarily of silicates and iron, which are unevenly distributed throughout the system and give it its variations in color.

Countless small outposts were established in and around various ring objects, with the largest functioning as states in their own right with unique cultures and laws dating back before cheap space travel.

Shepherd Moons

The rings wouldn't look nearly as interesting if they didn't have any gaps in them. While some of them, particularly the enormous Rlan Division between the A and B rings, were created by resonant interactions with Verto and Lirtso, the majority of the gaps within the ring structure were formed by miniscule asteroids known as "shepherd moons". These moons were created from the same ring material as the rest of the rings, and barely have enough material to hold together by tensile strength.

The largest shepherd moons are host to embedded habitats containing millions of people, and were some of the earliest mining targets in the early history of the Lrenn. The resources found here were vital to allow Lrenn civilization to expand beyond Erdath's own sphere of influence.

Civilization

Urban Areas

Lrenn Effect on Erdath

The expansion of the early Lrenn across the planet resulted in the death of many of the contemporary species of megafauna. Agricultural civilization and the proliferation of farming also resulted in the destruction of many of the planet's old-growth forests, but all this paled in comparison to the ways the Lrenn affected their planet after industrialization.

During the industrial age and the rise of mechanized civilization, Erdath's natural environment was positively brutalized. Ocean acidification, the collapse of the temperature circulation due to global warming, plastic everywhere, and even several nuclear craters left behind by a particularly devastating world war are all on the list. Strip-mining of entire mountains devastated the landscape all for comparatively minuscule amounts of resources.

However, all was not lost, as the introduction of renewable energy enabled the Lrenn to begin to fix the damage their ancestors had wrought. The engineering of plastic-eating bacteria, pulling excess CO2 out of the atmosphere, careful recooling of the planet through the earliest Holias System megastructures, and the deep burial of nuclear waste in salt mines all went towards this end. The highest rate of extinction was still in the very recent past, and so most extinct species were able to be revived including some of the early megafauna. Reforestation was also well underway before the temporary pause in those activities with the conquest of the world's nations by the Erdathian Domain.