Aven

Aven is the fourth planet from the Sun. It is the densest and fifth-largest of the eight planets in the Asaran system. It is also the largest of the Asaran system's four terrestrial planets. It is sometimes referred to as the world or the Blue Planet.

Aven is the only celestial body known to accomodate life and supports millions of species, including a world-wide population of humans. This human population is grouped into some 200 nation-states.

Composition
Aven is a terrestrial planet - its surface is rocky. Its shape approximates an oblate spheroid, flattened along the axis from pole to pole and bulging around the equator. The interior is divided into layers by chemical and physical properties: a solid crust underlain by a highly viscous solid mantle above a liquid outer core which lies above a solid inner core.

The rigid outer layers (the crust and the outer mantle) are broken into pieces called tectonic plates. These rigid segments move around the planet, driven by convection patterns inside the mantle. Aven's tectonic patterns are responsible for earthquakes, volcanic activity, mountain-building, oceanic trench formation, and the movement of the continents over the course of history.

The abundance of water on the surface of Aven is a unique feature that distinguishes the "Blue Planet" from others in the Asaran system. Aven's water is believed to be responsible for the origins of life on the planet and also serves to continually change its surface features. Water is present in the form of oceans, seas, lakes, rivers, geysers, and glaciers and is a fundamental part of global weather systems.

Orbit
Aven rotates around its own axis, from west to east, once in about 24 hours with respect to the sun and once every 23 hours 56 minutes and 4 seconds with respect to the stars. This axis is tilted some 23.4 degrees from the orbital perpendicular. This causes seasonal change in climate, with summer occurring when a hemisphere is pointed toward the sun, and winter taking place when pointed away.

Aven orbits Asar at an average distance of 93 million miles away. A complete orbit of Aven around the sun occurs every 365.256363004 days.

Coras
Coras is a relatively large, terrestrial, planet-like satellite, with a diameter about one-quarter of Aven's. The gravitational attraction between Aven and Coras causes tides in Aven's oceans. The same effect has led to Coras' tidal locking: its rotation period is the same as the time it takes to orbit the Earth (27 days 7 hours 43.7 minutes). Because it is tidally locked, Coras always shows the same face to Aven.

Coras is widely accepted to be the result of an impact of a smaller protoplanet with the early Aven. This explains Coras and Aven's crust being of the same composition.

Human Civilization
The last great extinction 66 million years ago cleared the path for mammals to diversify. About seven million years ago an ape-like animal gained the ability to stand upright, and about two million years ago, the Homo genus developed. Humans evolved 400,000 to 250,000 years ago.

Aven reached approximately seven billion human inhabitants in November, 2001. More than 200 independent sovereign nations claim the planet's entire land surface.