By Gregg Giles
In the same manner in which areas of a large body of water may swirl in a circle when one passes their hand through it, so too can gravity be made to swirl into a circle. Upon looking at the entire galaxy, one must visualize that it all moves in the same direction. By suddenly moving something through that galaxy (such as another galaxy) it is possible to cause part of that initial galaxy to change directions. The result is an “eddy” of gravity, or something similar to a “gravity well”. The gravity eddy in turn pulls worlds and star away from the other systems and brings them into its own formations (binary and trinary star systems are perfect examples, but not all, of course, were created this way – some systems developed with two or more stars).
In theory, this is how a star cluster is formed. Over the course of time, the various arms of the galaxy have pulled upon each other, and cuased many of these star clusters to form. Such examples include the Regina star cluster in the Spinward Marches, and the Shtievdriadr and New Chronor clusters in the Fronzhatlivr regions.
Star clusters become more common coreward due to radically shifting gravity fields. In addition, the star clusters coreward tend to host a vast number of worlds rich in natural and radioactive elements.
The Rifts and Arms
Rifts are areas of space that are close to being completely absent of any stars, at least when comparing them to the arms of the galaxy, which are full of stars. Rifts are often composed of many lesser rifts, and may even contain many small islands of stars, referred to as “groups”. One such group is along the expedition corridor in the Third Rift. Arms are composed mainly of stars with a relatively close proximity to one another, and can also contain lesser rifts, as in the case of the Windhorn Rift in the Vargr Extents.
The Great Rift and the Lesser Rift, which seem vast to sophonts, are merely lesser rifts in the overall picture of the galaxy. Routes across most rifts to exist.