Overheating: A problem everywhere. The logistics of a post-scarcity society may have eliminated most material-supply problems; advanced ergtech may have made energy not a meaningful practical constraint; computer power may be an absolute bargain everywhere; but even with every fancy high-tech possibility up to and including neutrino-catalyzed cooling in play, the requirement for heat dissipation still enforces speed constraints on nanotechnology, density limits on computronium, causes problems for guns firing on full-auto, prevents stealth in space, and requires most heavy industry to be kept at least in orbit even if its customers are downwell. Damn you, thermodynamics!
Unobtainium: Of many kinds. Sophisticated materials science is one of the major areas of advancement in this particular universe. Of particular note: deuterium slush, metastable metallic hydrogen, helium-3 and antimatter (more specifically, antideuterium slush) for power, room-temperature superconductors, sapphiroids (the trade name for the high-grade kind is Adamant™ – not adamantium, because it’s not an element; after all, transparent aluminum has been used, even if accurate), carbon nanotubes, highly refractory cerametals and metallic glasses, muon metals, strangelets, raw tangle – oh, and fun nonbaryonic things like exotic matter (you make stargate frames out of it), gluonic string (held together by the strong force, thus with the best tensile strength available), and so on and so forth. Less elementally, various nanofluids with fascinatingly exotic behavior, nanotech composites, and smart and biomimetic materials (living metal, nanowell-bearing programmable matter, etc.), computronium (okay, that’s not an element either, but…), and again, and so forth.
And medically speaking, of course, immortagens.
Corícal Ailek. It’s not the oldest star system in the Transcend, nor the most central – two gates from Eliéra via Palaxias, one gate from Cinté, and one gate from Tessil – but it may well be the most important; the seething brain of the transcendent overmind itself.
Corícal had five planets once, according to galactographic records, but only the oldest, the indigo-green hydrogen-methane ice giant Saviáná at the far fringes of the system remains, its moons hosting refueling stations (some dating back to the system’s days as a stopover on the Cinté-Tessil route), reception habs for visitors, and the system defense force. The four small rocky planets that once orbited closer in to the primary have long since been dismantled, torn apart for construction materials along with the majority of the system’s asteroids.
After all, it takes a lot of material to build a Dyson swarm. Or even a partial Dyson swarm; the Transcend is yet young, and evidently feels no need to expand Corícal any faster than its processing needs grow, and so the three layers of the Corícal swarm still only fill a fraction of the circumstellar sphere.
The most complete of the three layers is the innermost, orbiting so close to the Corícal sun as to skim its corona. Golden-winged polyhedra soak up light and particles alike, beaming power and fuel to the complexes and terranes further out, and soothing the temperamental star’s emissions.
Further out, AI-hosting complexes, immense fractal chandeliers of organic crystal, orbit; photonic computronium glimmering with information light, communication lasers flashing between them and binding the Transcend’s core mind – for though it is scattered across processors throughout the Imperial worlds, this is the center to which they all answer – into one single whole.
And outermost, within the life zone of the star, orbit the hexterranes; open-topped hexagonal habitat-plates, walled to hold atmosphere, organized into a great free-floating lattice that will one day surround it, with scattered wells to vent the heat from the inner layers. Under the yellow-white light of Corícal, scattered across rainbow skies by the crystal computers of the middle sphere, the hexterranes play host to dozens of environments – oxygen, halogen, ammonia, methane, hydrogen, sulfide – each with its own paradisiacal ecology perfected for the comfort of the sophonts who inhabit it, or who come to visit the cathedrals, loreworks, contemplationaries, and estates of these cities on the edge of the heart of the light.
– Leyness’s Worlds: Guide to the Core Worlds