Shirus

Image of Shirus

Shirus is a habitable terrestrial planet and the first fully uninhabitable planet to be terraformed by the Terallan species. As such, it has a very high population and is also a major world of the Verdan Federation. It is the third major moon of Jevethra and has the second thickest atmosphere out of them.

## Physical Characteristics

Shirus is a large moon of ~0.9 Terrestrial Masses. It has less water coverage than Teralla, and so has slightly more desert regions. Otherwise, it is the most Teralla-like planet known and a perfect example of the success of terraforming. It has a relatively small iron core relative to its total radius, and as such has a lower gravity than one would expect.

Before terraforming, Shirus was a desolate hellscape. It had a thin, almost nonexistent atmosphere covering endless, bone-dry rocky fields. However, the first missions appeared to confirm the existence of dry river valleys and hydrological erosion patterns, suggesting that the world was naturally habitable long ago. It almost certainly did not evolve multicellular life at this point, however.

## Atmosphere

Shirus' atmosphere is a mixture of Oxygen, Nitrogen, Carbon Dioxide, Argon, Neon, water vapor, Krypton, Xenon, and various trace gases with a density roughly 1.6x that of Teralla itself. Due to the terraforming process, Shirus is perfectly habitable for Terallans and a number of other Verdan Federation species.

## Climate

Shirus' climate is primarily driven by its landmasses and tidal forces from Jevethra. Similar to Teralla, Shirus' continents drive weather patterns, but due to higher ocean cover the weather is more predictable.

Shirus' relationship to Jevethra also helps to control its climate. Tidal lock to its parent planet means that Shirus has far longer days than a freely orbiting planet likely would. Longer days means that there is a larger temperature differential between the day and night side, inducing very strong winds.

Unlike Teralla, Shirus has little to no axial tilt, rendering seasons nearly nonexistent. Thus, a mostly uniform latitudinal temperature gradient exists from the equator to the poles.

## Orbit and Rotation

Shirus orbits Jevethra once every 27.50298833 days, and rotates in the same amount of time, because it is tidally locked. Because of this, it's aforementioned strong storms are partially dampened by its slow rotation. It's orbit is inclined by 4.913º and has a low eccentricity of 0.05.

## Life

Because of Shirus's large similarities with Teralla, life found here is largely similar. Due to Shirus' thick oxygenated atmosphere and lower gravity, life here is better able to fly, making avians a much larger group of species than on Teralla itself. The majority of the continents are covered in dense jungles, with trees many times larger than trees on Teralla. Shirus' predominantly wet climate and lack of large mountain ranges makes rainshadows nonexistent, which means that deserts are rare on the planet.

Ocean life consists of predominantly vertebrate fishlike creatures using anguilloform, subcarangiform and carangiform propulsion, alongside enormous amounts of static life-forms such as limpets and razor-sharp mussels. One of the most biodiverse regions in the oceans of Shirus is the great kelp reefs, which dominate the shallows near the continents. Many Shirusite plants and animals use bioluminescence for various purposes as well, and the oceans are lit up at night by bioluminescent plankton.