Strictly speaking, the classic definition of a Dyson sphere is “an artificial shell intended to capture all energy emitted by a star,” and of the known artificial worlds in our galaxy, most are intended just to capture energy. By the time a civilization becomes advanced enough that a Dyson sphere becomes a necessity, it is also advanced enough that it has ways to get around having to live on or in the structure so constructed. Of 87 Dyson spheres and 7 Alderson discs so far known, 70 of the Dyson spheres are the sole province of the AllEnders, who use that truly stunning amount of captured energy to maintain a pocket universe lovingly modified to their specifications and special needs. (60 stars are for the pocket universe maintenance, and ten for the equally mind-shaking amounts of energy needed just for wormholes to pass information between their universe and ours.) While theoretically a Dyson sphere has the potential for the interior surface area equal to roughly a billion Earths, without finicky and energy-hungry gravitic generation to keep people and fixtures with their feet in the right direction, setting up homesteads on the interior surface is problematic. Only two Dyson spheres known rotate to produce enough centrifugal force to simulate Earth-typical gravity, which means their atmospheres coalesce around the spheres’ equators and leave the rest of the spheres in low-gee or zero-gee vacuum. Only one produces an atmosphere safe for oxygen-breathing lifeforms (the other is a toxic smog of nitrogen compounds and methane, used as a reservoir for industry), and its maintenance is an example to the rest of the galaxy on maintaining their own atmospheres.
When creating an Earthlike biosphere within an artificial construct, it’s not enough to build a rock and soil substrate on which to grow plants and their analogues for oxygen production. The obvious issue with that substrate is that wind and precipitation break down rock and move soil, eventually leaving it all in the lowest portions of the sphere’s rotational area. The less obvious issue is that during erosion and deposition, sediments and solutions react with available oxygen, producing carbonates, silicates, and oxides. After enough time, without a way to break these down, any available oxygen finds itself bound within rocks and rust, and the atmosphere thins accordingly. On worlds with tectonic plate subduction or comparable processes, those rocks and rusts are shoved into the mantle of the planet, where they melt and outgas via volcanic outlets. On a world where the available rocks lie on a relatively thin layer of base construction material, those volcanic outlets could never form on their own, so they have to be created.
Dyson Sphere 10 was either abandoned approximately 2 million years ago or never inhabited by its builders in the first place, but it has a habitable zone roughly comparable in surface area to 2 million Earths. Instead of having rivers and oceans carved into the shell, the whole zone is a series of rock flows like glaciers, all gradually sliding via erosion and gravity toward the equator. There, self-repairing machinery gather and grind rock, soil, artifacts, and anything else sliding that far, transport the debris to the edges of the habitable zone, and melt it and extrude it into gigantic piles that repeat the process. The resultant gases are then gradually released into the atmosphere, keeping up a nitrogen/oxygen/carbon dioxide/water cycle that might require an addition of supplemental material to replace that lost into its star or through airlocks…in about 300 million years.
The gas vents and extruders themselves aren’t concealed or hidden in any way: apparently the sphere’s designers preferred to remind all as to the tremendous efforts made to make such a world as gentle as it is. Because of that, and the missing designers, the habitable zone is home to at least 30 sentient species, three of whom only known from this Dyson sphere. While the sphere’s rock reclamation system is nearly foolproof, it requires occasional maintenance, and the efforts by all 30 species to work together to do so is without compare within the known universe.
Dimensions (width/height/depth): 18″ x 24″ x 18″ (45.72 cm x 60.96 cm x 45.72 cm)
Plant: Nepenthes ventricosa x hamata
Construction: Glass enclosure. polystyrene foam, vacuum-formed plastic, found items.
Shirt Price: $250