The Human Metacivilization is the name given to the amalgamation of all Earth-descended life across the Milky Way Galaxy. This includes AIs, uplifted species, genetically engineered life; essentially everything that, without humanity, would not have existed.
The Human Metacivilization is a rough oblate sphere, most thick around the galactic plane and tapering off into nothingness in the galactic halo. With a diameter of forty thousand light years, the metacivilization is expanding constantly into surrounding space.
Structure
The metacivilization is shaped, from an outside perspective, like an onion. Differing layers are placed on top of each other, defined by prominent "exoduses," or times of accelerated colonization. There are three of there layers; the Inner, Middle and Outer Spheres.
Inner Sphere
The Inner Sphere, centred on Earth and the Solar System, is a two thousand light-year wide rough sphere that contains the most prosperous and developed areas of human civilization. This is where the ancient and decadent societies and empires reside, and worlds here are old and well-developed. Living standards are high, and most societies are egalitarian, post-scarcity and highly or entirely automated.
Middle Sphere
The Middle Sphere is a larger, wider sphere layered on top of the Inner Sphere. It stretched approximately eight thousand light years, and houses the newer, developed or developing societies. Towards the inner boundary of the sphere, closer to Earth, the nations mirror those of the Inner Sphere, in structure and economy. However, as you get farther and farther away, things change and new and dynamic things arise. Most of modern astropolitics involves developed and powerful polities across the Middle Sphere asserting their dominance on surrounding nations.
Outer Sphere
The Outer Sphere is the final and badly-defined last sphere of humanity. There is no clear edge of the Outer Sphere, as it fades off to infinity. It isn’t even shaped like a sphere, as by this point the plane of the galaxy has forced it into a dinner-plate shape. The Outer Sphere is a land of contrasts - some areas house vibrant empires, convinced of their own superiority, whilst others host kind and humane outposts, helping weary travelers in their journeys across the stars. The Outer Sphere is akin to the old Wild West - a place of endless opportunity, but with a fair share of danger and adventure.
These three spheres are only rough outlines that help life make sense of what it has created. Many exemptions and exceptions can be find, and nothing said above should be taken as fact, true for everything in their respective spheres.
History
For a history of Humanity, please see History of Humanity.