Asgard

Asgard from the L2 point

Astudillo and smaller Asgardian satellites

**Asgard**, officially designated **Luyten b** or **Gliese 273b**, is a terrestrial planet orbiting the red dwarf star Luyten's Star. One of the most Earth-like planets ever settled, it lies just 12 light-years from Earth. It has two major moons, Astudillo and Defru, the former of which is larger than Mercury in the Sol System, and a number of minor moons. Asgard serves as the federal world of the United Colonies and home to the General Assembly.

Discovered alongside its sister worlds in the 2010s, Asgard was one of the first targets for colonisation thanks to its Earth-like conditions. Widely considered a "second Earth", Asgard quickly became the most populous of the colonies, its power and influence second only to Earth. After the terror attack known as the Lesson devastated Earth, the U.C. General Assembly was forced to relocate to the nearest stronghold system, that being the Luyten system; Asgard thus became the capital of the United Colonies throughout the Great Galactic War, a title it retained post-war when it became clear that Earth could not be repaired. In the decades since, Asgard has become humanity's "second homeworld" and wields power and influence second to none in the Settled Systems.

## History

Luyten's Star b was discovered in the 2010s using ground-based telescopes operated by the World Initiative for Space. Subsequent observations determined it was a super-Earth well within its star's habitable zone, though its composition and atmosphere remained a mystery until deep space telescopes were launched. By the end of the 21st century, Luyten b was determined to have an Earth-like atmosphere with stronger gravity and multiple moons.

Luyten b was one of the first extrasolar worlds to be colonised during the interstellar phase of the Great Migration; its close proximity to Earth and comfortable conditions quickly established it as a powerful colony. It remained loyal to Earth during the Herschel Wars and joined the United Colonies after the Collective's collapse. The decisive Battle of Asgard in 2241 eliminated any U.C. hopes of reclaiming the rebellious Herschel Nations. Despite the damage it sustained, Asgard emerged as second most powerful world in the Settled Systems, second only to Earth itself.

Construction of Asgard's capital, Arcadia, began soon after its colonisation; the planet's status as a local hub, one located in a resource-rich system around a calm star, allowed Arcadia to grow much larger than other extrasolar cities.

## Overview

### Orbit & Rotation

Asgard orbits close to its host star: one full revolution around Luyten's Star takes about 18.6 Earth-days at an average distance of 0.091 AU, much closer in than Mercury, which has a year of 88 days and an orbital radius of 0.387 AU. However, because the host star is so dim, Asgard falls right within the system's habitable zone and only receives 6% more starlight than Earth. While most planets this close to their parent star are tidally locked, Asgard has a moderately high orbital eccentricity of 0.10 ± 0.08; as a result, Asgard spins once on its axis in 16.5 Earth-days, meaning its day is almost as long as its year.

### Atmosphere & Climate

Asgard's atmosphere is remarkably similar to Earth's; it is primarily composed of nitrogen and oxygen with trace amounts of carbon dioxide and other greenhouse gases, producing an average atmospheric temperature of 19°C. Asgard's thick atmosphere is able to evenly distribute this heat across the planet, warming the night side during its long rotations.The oxygen content is higher compared to Earth, at around 22%, as is that of greenhouse gases; this present oxygen content was brought down from the original 23% via terraforming when the planet became widely settled.

Asgard's axial tilt of 30.49221° produces much more extreme seasons than Earth; summers are hotter and winters are colder than the human homeworld. The subtropical zone is thinner compared to Earth, while the polar circles cover a larger area of the planet's northern and southern expanses. These temperature differences make farming Earth crops difficult; native crops have been cultivated and genetically engineered for human consumption.

Like Earth during the height of industry, Asgard has undergone climate change in the centuries since humans arrived. Due to circumstances including its more extreme axial tilt, smaller subtropical zone and comparatively weaker biodiversity, extreme weather events are relatively common and have only been made more intense by anthropogenic changes.

## Moons

Asgard has seven moons, of which only two, Astudillo and Defru, have enough gravity to become spherical. The remaining five minor moons have long been stripped of their resources.

### Major Moons

Astudillo and Defru are among the largest moons in the Luyten System; only Yggdrasil's are larger. Astudillo, the larger of the two moons, has a diameter of 5,090 kilometres, slightly smaller than Titan in the Sol System; Defru is just over 3550 kilometres, slightly smaller than Io.

## Life

Asgard is home to a diverse native biosphere that evolved around 3.75 billion years ago, about fifty million years before life first appeared on Earth. Asgardian life is carbon-based and found in all the planet's biomes, from the poles to the deserts, to the depths of the sea. In accordance with Interstellar Taxonomy Society guidelines, the taxonomic classification and naming sytems for alien life, including Asgardian, are the same as those for Earth life.

Like Earth, Asgardian life belongs in one of three domains: archaea, bacteria and eukarya. Asgardian prokaryotes (archaea and bacteria) are remarkably similar to Earth's, while eukaryotic life possesses major differences. In many ways, Asgardian eukaryotes are comparable to Earth during the Mesozoic era, the time of the dinosaurs: reptilian organisms are the dominant animals, aside from humans; mammalian analogues are small and reside primarily underground; the oceans are inhabited by titanic fish-like creatures; and the skys are ruled by flying reptiles.

### Plants

Asgardian plants use carbon dioxide to photosynthesize and release oxygen as a waste product, just like on Earth. The dominant land plant species are gymnosperms, vascular, cone-bearing, non-flowering plants that produce seeds without a coating; this contrasts with Earth's flora, in which the dominant land plants are angiosperms, and is very similiar to prehistoric Earth. Flowering plants are mainly restricted to the tropics due to the large polar and smaller subtropical areas of the planet.

Under the red light of Luyten's Star, Asgardian plants appear light blue to the human eye; instead of chlorophyll, which reflects green light, Asgardian plants utilize phycocyanin, a protein that absorbs orange and red light to produce a light green-blue colour.

### Animals

Asgard is dominated by "xenoarchosaurs", dinosaur-like reptilian organisms that range from a few inches long to more than 30 metres. Asgard is not the only planet home to xenoarchosaurs but it displays comparatively more morphologic diversity, even more so than the archosaurs of Earth's past. Aside from xenoarchosaurs, there are xenoinsects, xenofish and a variety of xenoreptilians.

   Oxygen transport in animals is carried out by hemerythrin instead of hemoglobin; while less efficient, Asgard's oxygen-rich atmosphere enables animals to respire at rates comparable to Earth life.

Despite its high gravity, Asgard is home to some of the largest animals in the Settled Systems, namely *Astrotitan*, a sauropod-like xenoarchosaur that roams the plains and forests of both Vaalbara and Chilenia; with maximum confirmed lengths of 33 metres (108 ft), *Astrotitan* is the largest land animal yet discovered. Its only natural predator was the gigantic Asgardian Terror Worm, a subterranean annelid that reached lengths of 28 metres and was hunted to extinction due to the threat it posed to human settlements. With the Terror Worm gone, the planet's current largest predator is *Ursasuchus*, a bear-like xenocrocodilian that prowls the deserts of Chilenia hunting sandhorns.

## Human Geography

Home to more than 15 billion people, Asgard is the most populous planet in the Settled Systems and the most populated planet in human history; at its peak, Earth's population only reached just over 12 billion. Thanks to its slightly larger size, Asgard's sustainable population is 13 billion compared to Earth's 8 billion; therefore, without resources brought in from the rest of the Luyten system, such as crops on Yggdrasil's moon Hvergelmir, Asgard's current population would be unsustainable.

Distribution and density of human population varies greatly around Asgard, though the majority live in the northern hemisphere on the supercontinent Vaalbara, with around 35% living on the smaller continent Chilenia in the southern hemisphere. The supercity of Arcadia houses 70% of Vaalbara's population and covers more than half its land area; Chilenia, considered a nature reserve, is dotted with frontier towns, outposts and scientific facilities. A fraction of Asgard's population lives on Astudillo and Defru though the latter is only occupied by SPACECOM, which maintains a listening station and railgun on the moon's far side.

Asgard is divided into four countries, all loyal to the U.C.: the Supercity of Arcadia, the Cook Republic, the Low Countries and the semi-autonomous Dolorian Republic. Arcadia is a federal city directly governed by the United Colonies, while the Dolorian Republic is governed by the Dolorian Church, the largest Dolorianist institution in the Settled Systems.