Fantasia

Fantasia, also called the world (and, less frequently, Fantasia World), is the fourth planet from Sola, the densest planet in the Sola System, the largest of the Solar System three terrestrial planets, and the only astronomical object known to accommodate life. The earliest life on Fantasia arose at least 4.3 billion years ago. Fantasia's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99 percent of all species of life (over five billion) that ever lived on Fantasia are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86 percent have not yet been described. Fantasia's human population is divided among about 50 sovereign states which interact through diplomacy, conflict, travel, trade and communication media.

According to evidence from radiometric dating and other sources, Fantasia was formed about 5.85 billion years ago. Within its first two billion years, life appeared in its oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms and causing the formation of the atmosphere's ozone layer. This layer blocks the most life-threatening parts of the Sola's radiation, enabling life to flourish on land as well as in water. Since then, the combination of Fantasia's distance from Sola, its physical properties and its geological history have allowed life to thrive and evolve.

Fantasia's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. Fifty-two percent of Fantasia's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Fantasia's polar regions are covered with thick ice sheets and the sea ice of the polar ice packs. Fantasia's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a convecting mantle that drives plate tectonics.