B) Earth and Luna

The Earth that the human race abandoned was subject to a "moist greenhouse effect", largely due to instabilities in the sun. Scorched by the sun for nearly a century, wracked by unbelievably intense storms, the Earth is now largely lifeless. Most of the planet’s oceans boiled into the atmosphere and then off into space, heating up the surface, leading to a nearly endless cycle of storms beyond imagination. Eventually the oceans will completely escape the atmosphere, leaving Earth dry and uninhabitable. For now, the Earth is both extremely hot and unbelievably humid, as most of Earth's water is now water vapor in the atmosphere. Most of earth is covered with steaming mud, itself filled with countless industrial toxins from the ruins of human civilization. The combination of heat and humidity killed off much of Earth's biosphere, leaving it wide open to heat-tolerant fungi and other micro-organisms. As a result, unprotected humans that are exposed to the environment will often develop fatal skin and respiratory infections within days. Dry deserts are found only along the equators and the continental interiors, which are now inconceivably barren and lifeless. The oceans of the world are much reduced and unrecognizable, existing only as shallow, silty seas in the trenches and basins of the former ocean floors. Little life remains in these seas, which are often choked with extremophile bacteria and a few very hardy invertebrates. Higher lifeforms can only be found in the North polar regions, where the ambient temperature remains hot but tolerable.

Most signs of human civilization have been eroded into oblivion, and the air is so hot (170* F at the equator) that life is only possible near the polar regions. Humans are known to exist around the muddy seas of the Arctic Basin, but they maintain no contact with the rest of the solar system. It is uncertain what sort of hellish existence the humans dwelling there must live; food and clean water are scarce, and they appear to have no technology visible from orbit. No settlements large enough to be called "towns" exist, and the total population is probably less than a few thousand. Antarctica is now a dry, lifeless plateau. Its isolation and climate make it an ideal location for Novy Vostok, a research station maintained by the Free Luna Soviet. Novy Vostok houses about 500 scientists and staff who monitor Earth using remote drones and local instruments. They are especially interested in Earth's radically changed but still extant biosphere. The Free Luna Soviet periodically toys with the idea of "re-terraforming" Earth, now that the sun is known to be relatively stable. It is unlikely that anything will come of the idea, which would require the combined efforts of the rest of the solar system to achieve.

Luna and the Free Luna Soviet

Earth's moon (Luna) was initially settled in the 2040's, and over following decades played a huge part in the colonization of the solar system, and later the construction of the Exodus Fleet. Towards the end of the 21st Century, the colonies were stripped of all usable materials and equipment, and the very last crew evacuated in 2098. Luna lay empty, a cold memorial to the human race, that would orbit a dead Earth until consumed by the sun.

Over a century later, humans returned to Luna. Political dissidents from the Saturn Federation arrived on Luna in 2200 and set about building clusters of underground habitats on Luna. Where possible, they rehabilitated the old existing colony complexes. Over the next twenty years, a stream of immigrants left Saturn's intensely hierarchical and regimented society, and resettled on Luna. The tiny colony became a safety valve for the Saturn Federation, and by 2300 had reached a population of about a million people. Luna developed a simple mining economy, trading resources with Mars in exchange for foodstuffs until self-sufficiency could be obtained. Furthermore, occasional sorties were made to Earth to acquire water, organic materials, and a few valuable bits of abandoned technology.

By 2500, Luna has developed into a relatively prosperous colony, with a population of about eight million people scattered between a dozen cities. All of these cities are members of the Free Luna Soviet, a relatively free socialist society of the sort common to 20th century Europe. Society retains the four grade system, but is more meritocratic. They have embraced democracy, but remain more paternalistic than 20th Century Americans would tolerate - a product of the extensive social safety net and the general tone of society. The Free Luna Soviet has a relatively limited military, preferring to shelter behind the mass-drivers and lasers of its lift industry; industrial facilities that also serve as fearsome weapons. Despite being the one of the smaller planetary states, the Free Luna Soviet maintains outposts on Earth, Mercury, Venus, and unofficially lays claim to the entire inner system. This is a serious point of contention for Saturn, which sees itself as the true inheritor of the Solar System. The Free Luna Soviet maintains reasonable relations with Mars and the Belt Cities, but has a kind of "cold war" going with the Saturn Federation, who would love to gain control of the inner solar system.