The universe of the Silky Way is broadly a grounded science fiction universe, but there are some terms introduced in the scope's content which need definition. This page is where those definitions can be found, and will be linked to wherever relevant.
Seed Cluster
A Seed Cluster, not to be confused with a more generic star cluster, is a structure in which the vast majority of life in the universe will arise. It generally comes in the form of a star cluster, often with an associated nebula, although the nebula will have dissipated in older seed clusters. Seed Clusters vary widely in size, with the smallest recorded being under fifteen light-years in radius, and the largest topping out at almost a thousand.
Within a seed cluster, life abounds, with the Vernarca Nebula alone home to almost thirty sapient species. Beyond it, however, habitable planets are rare to nonexistent, with the voyage of the FSS Kareland uncovering only a few, hundreds of light-years apart. The space beyond seed clusters is also generally extremely resource-poor, with low-metallicity stars being the norm and multiple-planet systems being almost as rare as habitable worlds. Seed Clusters are thus the site of virtually all civilization in the known universe.