Our galaxy, named "Altaleana", is a spiral galaxy with two spiral arms and a large central oval in the centre. It is about 110 000 light-years in diameter and 1150 light-years tall. It contains roughly 200 billion stars. Of those, we estimate 30 million - or 3 in 20000 - are inhabited with intelligent life. Planets inhabited by intelligent life are referred to as worlds. These worlds are spread out across the galaxy, though neither the two spiral arms nor the central oval bulge of the galaxy contains many of them, as these areas are generally too volatile. Even with this clustering, there are still pretty vast distances between these worlds. The average distance between a world is around 68.5 light-years. Fortunately, we have technology available that allows us to cross these distances, even if it can easily take several months to get from one world to another.
History and Naming
The galaxy has been around far longer than any of the worlds inside it. In fact, some of the stars in the galaxy are estimated to be almost as old as the larger universe. The larger universe is estimated to be more than ten billion years old, which is estimated based on primarily how fast distant galaxies seem to be moving away.
This presents an interesting discrepancy with the concept of Average Convergent Time , which, from research done in that area so far, suggests that most convergent worlds have seen their cultures evolve for almost 8500 years, a significant shorter time span than the age of the universe, or even of most worlds that are inhabited by these cultures. It is unclear what exactly causes this discrepancy, current Convergence theory holds that 8500 years ago the convergent force became active.
One thing that is easier to trace is the naming of the galaxy and some of its parts. The name "Altaleana" is based on an ancient language spoken by members of The Collective before they became a space-faring society. It roughly translates to "The Gaze of the Great Serpent", which is an allusion to how the galaxy looks from their home world.
This name, along with several similar names for other features of the galaxy in the same language, was carried with the members of the Collective when they started spreading their interstellar travel technology to other worlds. Many of those worlds have their own name for these things, yet like many other things related to interstellar travel, everyone learned the Collective's names for these things in addition to their own, so when contact happened between interstellar worlds, they inevitably used the Collective's names for these things.
Astrography
The galaxy is a so-called "barred spiral galaxy" with two spiral arms. One spiral arm is called the Yasar Arm and the other is called the Hakun Arm. The Yasar arm has two spurs, the Coreward Yasar Spur and the Rimward Yasar Spur. The Hakun arm has a single spur called the Hakun Spur. The galaxy contains a single large ellipsoid shape at the centre called Shalsuba, which forms the bar of the barred spiral. At the centre of the bar, and the centre of the entire galaxy, is the supermassive black hole called Madkas.
Most worlds are actually located outside of the spiral arms and the bar, as those areas feature a lot of star birth and death, which makes them too volatile for planets with life to survive a long time. These worlds are located in four main areas, the Coreward Worlds, Hakun Worlds, Yasar Worlds and the Trailing Worlds. These are still areas of a very large volume of star systems, even if they are not as dense as the arms.
The Coreward Worlds
The Coreward worlds is a volume of space in between the Hakun Spur and Shalsuba. It is a volume of roughly 345 billion cubic lightyear, encompassing around 2.2 million worlds, according to current estimates of world density in the galaxy.
The Hakun Worlds
The Hakun Worlds is a volume of space between the Hakun Spur and the Hakun Arm, bordered off by Shalsuba on the spinward side and running until roughly the start of the Hakun Spur on the trailing side. It is a volume of roughly 580 billion cubic lightyear, encompassing around 3.7 million worlds.
The Yasar Worlds
The Yasar Worlds is a volume of space between the Coreward Yasar Spur and the Rimward Yasar Arm, bordered off by Shalsuba on the spinward side and running until roughly the start of the Hakun Arm on the trailing side. It is a volume of roughly 590 billion cubic lightyear, encompassing around 3.8 million worlds.
The Trailing Worlds
The Trailing Worlds is a volume of space at the end of the Rimward Yasar Spur, in between the Hakun Arm and the trailing end of the Yasar Arm. On the trailing side it ends where the Yasar Arm ends. It is a volume of roughly 170 billion cubic lightyear, encompassing around 1.1 million worlds.
Planets and Worlds
Most of the stars in the galaxy have planets surrounding them. In fact, our current estimate is that each star has on average five planets orbiting it. Most of these planets can be separated into two types, those with a gaseous core or those with a rocky core.
The gaseous planets tend to be larger than the rocky planets, in fact they are often referred to as "gas giants". They can be useful sources of various resources for those with the capabilities to harvest them, but are otherwise mostly uninteresting. Many gas giants will have a number of moons surrounding them.
Rocky planets can be barren and without atmosphere, with a thick, toxic layer of gases as atmosphere or anything in between. Some of the rocky planets exist in an area not too close to the main star but also not too far away, the so-called habitable zone. These, if they have the right atmosphere, can actually have life on them. And some of these planets with life will have the convergent force acting on them, turning them into worlds.