Monday, November 26, 2012

On Wet Stars 1; Critique of the Rickety Big House

               On Wet Stars
               and Sustainable Astroengineering

               A blog in five parts:
1. Critique of the Rickety Big House
2. Steppenwolf
3. Wet Star Nemo
4. Conversation between Hellerstein and Nordley
5. Visit to a Wet Star

               1. Critique of the Rickety Big House

               This series of five blogs is a critique of astroengineering as a fantasy of control. This includes Dyson spheres and Ringworlds. This series also suggests an alternative astroengineering project. I call it the “Wet Star”; and I post it here for people to check and critique.

               Consider the Dyson Sphere, of Kardeshev level 2, which captures all the energy output of a star. It could be a “Dyson swarm” of separate habitats, as originally conceived; or it could be a solid shell. Either design choice is troublesome. If a solid shell, then made of what super-material, and how to keep it stable? And what about maintenance?

               Or is the Sphere instead separately orbiting habitats? What a traffic problem! If habitats collide, then they’ll spew debris which will hit and break up other habitats; a cascade! I suspect that, without continuous traffic monitoring, within a mere megayear the habitat fragments will accrete to form planetesimals.

               Niven downscaled the Sphere to the Ringworld. It’s a solid structure, monstrously big, vulnerable to asteroid strikes. Also you need material with the tensile strength of nuclei. Also its orbit is unstable, and it’ll scrape the sun unless you put in attitude jets; and Niven had these kill a billion neighbors every time they fire. So Niven’s Ringworld is naturally a technofascism. Yuck.

               Iain Banks, who is as unrepentantly utopian-socialist as Teapot-Dome-grandheir Niven is cynical-capitalist, downscales the Ringworld even further to his “Culture” star-civilization’s “Orbitals”. An Orbital is a Ringworld-like band, with the radius equal to that of the Earth-Moon system; a Kardeshev-level 1 cinvilizaton. It rotates in one standard day; with the result that it is at one standard gee. No need for shadow squares for a day-night cycle, just tilt the Orbital’s axis of rotation a bit from its orbital axis. Also no sun-scraping or attitude jets; but you still need super-materials. Banks gives each Orbital a “Hub Mind” - that is, a meddling paternalist posthuman AI running everything.

               These three visions have much in common. They are fantasies of control; they are gigantic. They are also... how shall I put this... brittle. Untopological. Slackless. There’s no blob factor allowed. That Orbital has got to spin just right or it’ll fly into pieces; so naturally it needs a busybody in charge. So naturally, the damn thing’s doomed. Ditto with Ringworld and Dyson Sphere.

               All of these systems must be actively maintained, with constant monitoring, adjustment and repair; which implies a living civilization continuously inhabiting the gigastructure. But civilizations rise and fall; they cannot be continuously maintained for longer than mere millennia; far too brief a timescale for astroengineering!

               I propose that astroengineers must design with a timeframe beyond the lifespans of nations, religions, civilizations, languages or even species. Vital systems must be passively self-maintaining over megayears or even gigayears.

               Astro-engineers, take note: the stars are not just big; they are also old.

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