User blog comment:GrandMethuselah67/Lore Sheet: The People's Imperium of Neohumanity/@comment-4867780-20150810003841/@comment-4867780-20150810211341

Galaxies like the universe at large are "made" of almost empty spaces for the overwhelming majority of their "territory" (how many light-years between each star ?). So while I agree there are huge quantities of materials available from a smaller perspective (enough for the U.R.H to thrive once they master transmutation), encompassing the the Milky Way in a galaxy-wide Dyson Sphere (do you realize the sheer scope of the task ? ^ ^; ) would require exponentially more materials than its empty territory seems to hold.