Quint said:
... and things like arcologies, beanstalks, space habitats, etc. exist at the various appropriate TLs.
Here is a bit of fiction I wrote for a Milieu 0 campaign, and the Mega-Structures that kept the population alive... for a while.
Knash
2216 B8A6000-7 Ba 023 M0 V
Tragically Knash is typical of the worlds whose populations did not survive the Long Night. Once a beacon of Vilani technology, it now stands in ruin.
Knash itself is a very geologically active world, with thousands of volcanoes spewing millions of tons of carbon dioxide into the atmosphere. As a Solomani crew once put it...
"Atmosphere is 71 percent nitrogen, 21 percent oxygen, traces of argon gas."
"Just like home."
"Only if you're breathing through an exhaust pipe. CO2 is over 3 percent. Two minutes without a suit, you're dead."
Actually the weather is quite mild, everything considering, so a full environment suit is not necessary. But the use of oxygen tanks are.
The red dwarf star the planet orbits around is cool enough that a runaway greenhouse effect has not occurred, but the atmosphere is tainted enough to keep the temperature quite comfortable for humans. Sea-life is abundant, enjoying a very diverse eco-system. But, so far, plant life is only now making a significant hold on land. Scientists think this should occur naturally in the next one to two million years, with amphibians crawling out of the seas soon afterwards.
Red dwarfs commonly cause intense solar-flare activity and high ultra-violet radiation output. However, this particular red dwarf seems to be old enough that such activity has mitigated somewhat for the last half-billion-years or so, long enough for life to take hold.
During the height of Ziru Sirka, (the First Imperium,) the Valini built a dozen massive Plexiglas domes to protect a population of six million people scattered across the "eastern" hemisphere -- the side of the planet tidally locked towards the sun. But as the Long Night descended, and interstellar trade ceased, the population no longer had the technology to maintain the domes that protected their continued existence. One by one, over the course of six centuries, each eventually cracked, and failed. Massive graves have been found underneath each of the cities, with the remains of hundreds of thousands of people huddled together in sub-terrainian caves they tried to seal off from the encroaching, poisonous atmosphere.
Situated equally between Sylea and Zimiin, the two "core" worlds the Sylean Federation have been jointly trying to repair the smallest of these massive domes in order to begin recolonization of the planet, but it's been slow going. While they have established an underground "B" class starport in order to facilitate operations, they have only been able to bring Knash's industry to a Tech Level of 7, which is far insufficient to repair the damage to the domes built so long ago.
The domes, measuring kilometres across, obviously cannot be built off-world and transported to the planet.
The Sylean Federation, and now the nascent Third Imperium, maintain a presence in the system in the form of two or three patrol craft to chase off anyone who might wish to interfere with recolonization efforts, or somehow lay claim to the system themselves.
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... so as to harness all of the energy radiating away from that white dwarf.
). The difference is that natural environments are capable of "self-healing" through natural processes ... while ringworlds are not. As engineered arcologies, ringworlds require active MAINTENANCE measures in order to be sustainable ... unlike planets.
