 The Dyson Sphere was constructed over a million years ago by an unknown race, and abandoned several thousand years ago, presumably due to instability in the central star. The carbon-neutronium shell is approximately 2500 metres thick, and is presumed to contain circulation equipment for the Class-M environmental systems as well as artificial gravity and power generators, but this is an as-yet untested hypothesis, since only limited access has been gained and sensors are unable to penetrate the material. The upper atmosphere polarises to provide an artificial day/night cycle of 15.4 hours of light and 10.2 hours of darkness.
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