- You may be looking for the general concept.
The Expansion was an era of colonisation by humans when Earth was on the brink of a period of five thousand years of inhabitability. (TV: The Ark in Space) Though in the following millennia nobody came to Earth and far from the freight routes, humanity thrived throughout its many colonies. (TV: The Sontaran Experiment)
It was around this time that the first star-pioneers reached Andromeda. Eventually that whole galaxy became dominated by humans. [source needed] Another particularly successful colony was GalSec, which in ten thousand years carved out an empire with bases throughout Mutter's Spiral. (TV: The Sontaran Experiment) The time was marked by war between GalSec and the Wirrn. (AUDIO: Wirrn Dawn)