Impendia is a small carbon planet, the fourth from its star, Xollum, in the Xollum-Xolrut System. Due to an active geology, the planet has formed a dense cloud layer of hydrocarbons, above which is an atmosphere of oxygen and carbon dioxide, with microscopic particles of ferrous carbonate, giving the planet its pale yellow-pink color. The surface of the planet is largely uninhabitable, with the exception of stratospheric plateaus, which reach a high enough elevation that they breach the hydrocarbon layer.
Although microbes in the atmosphere consume the ferrous carbonate dust circulating in its cloud layers, these particles are toxic to life and so helicitodrones must constantly keep clouds at a distance from open-air colonies. Fierce lightning storms also occur inside of these layers and high winds circle the planet at various latitudes. Temperatures and pressures on the planet's surface are similar to those of the Venusian surface, and those in the planet's upper atmosphere are similar to those of Earth at sea level.
Within the hydrocarbon troposphere, there are active volcanoes which erupt molten calcium carbide and boron carbide and leave vast diamond fields and hills. In addition to the volcanoes, taller graphitic prominences spew pure graphite and diamond, and it is theorized that some of these prominences could be composed entirely of diamonds.
The interior of Impendia is probably consisted of an iron-rich core, surrounded by layers of molten carbides, above which is likely a mantle of mostly graphite with vast deposits of diamond. The molten interaction with the solid core would be responsible for Impendia's significant magnetic field, slightly stronger than that of Earth, which is theorized to be the reason for the extraordinarily-close orbit of Umud, given its vast deposits of Sublimium and the known effects of Sublimium-quantum Resonance with the planet's magnetic field.
The surface of Impendia, its crust, has only been infrequently surveyed by ground researchers, but has been found to contain a majority of calcium carbide and boron carbide, with some excavations uncovering lesser deposits of silicon carbide and titanium carbide. There are believed to be vast oil lakes and tar fields as well, though no research expedition has ever found them.
The stratospheric plateaus (called 'strateaus'), are consisted mostly of calcium carbide with various other elements.
Impendia has numerous native lifeforms which call its clouds and stratospheric plateaus home. All Impendian life has 5 base pairs in its genetic material, and can be classified as one of the following:
These are organisms which have a metabolism very much like Earth life, with analogous cellular structures. They take in mineral resources from the calcium or boron carbide surface and other lifeforms, and produce oxygen.
The haze-archaeids mostly reside in the upper haze layers of the atmosphere, and synthesize carbon dioxide. Many species glow and 'bloom' at various times of cycle.
Structids are colonies of organisms that can in some cases grow to the extent of whole cities. These are analogous to plants in terms of Earth life, but are very precisely symbiotic with the lifeforms around them with respect to structure and function.
This branch of life is perhaps the most evolved on Impendia, with a very different biology to that of Earth life. Members of this branch evolved from some unknown boron carbide-based origin and have almost impermeable armor for an outer structure.
Colonization of Impendia began around 3810 E.I., or CS 22416 (see Measurements of Time).