A shared science-fiction setting — and the projects built in it.
“…the way of a ship upon the trackless deep, and the way of a lover with the beloved.” — Proverbs 30:18–19
The setting
Thousands of years ago an advanced human civilization settled a planetary system far from Sol. That civilization is gone. The humans who remain have no memory of what came before — they use its names fluently and could not tell you where a single one came from.
Three habitable worlds sit in the goldilocks zone. Around them turns the Dust, an enormous torus of gas and rubble where people scrape out a living beside lifeforms of a wholly different origin — organisms fully adapted to vacuum, neither animal nor plant.
The largest vacuum lifeforms are the sessile Strands — vinelike growths from thirty metres to thousands across, braided bundles of hollow Tubes. Dead inner Tubes carry the tension; the mature middle torus holds breathable air, faint bioluminescence, and people.
Settlements are crazy quilts of yurts, pods and guy-cables anchored to the tubewall in microgravity, lit by small fusion suns hung on the axis. There is no sky, no horizon, and no floor anywhere.
A corrosive contagion eating slowly through the Strands — three centuries to take one Tube. Slower than institutional memory, which is the frightening part. It gives back no reflection: it doesn't read as dark so much as missing.
No day and no night — only the fusion suns brightening and dimming. Waxing is the morning of that cycle; Waning its dusk, warming to orange as the light falls.
Two axes and nothing else. Sunward in toward the axis, wallward out to the crops. Along the Tube: tradeward, toward everybody anyone has ever met — and deepward, where the tubeways narrow and stop being anybody's business.
Trilaterally symmetrical, charcoal-skinned, three bulbous yellow eyes and a three-part beak. Domesticated and ridden — the settlements' hauling and travel through the Dust. They go hand over hand where there is anything to hold, and vent to cross the gaps.
A name that outlived its meaning
Tube names are route codes, not descriptions — the way a transit line's colour is a label on a map and not the colour of the tunnel. The Yellow Tube is not yellow. The Purple Tube is not purple and never was. A colour-coded network implies somebody who surveyed it, and that is exactly the sort of thing this civilization has lost.
Chart
A binary: a yellow primary a little larger than Sol, and a red dwarf companion far out on a slow orbit with a single habitable moon. Habitable-zone edges from the Kopparapu limits, orbital spacing from mutual Hill-radius stability, the binary from Holman & Wiegert — worked out rather than invented, because the settlement is thousands of years old and the terraformers arrived long before that.
The film
An anime-inspired, Ghibli-influenced animated feature. Pelsa, a curious sixteen-year-old, slips into a sealed derelict section of the Purple Tube — and finds the Blight that has been quietly eating through the Strand for decades. Her discovery forces a farming settlement of thirteen thousand people into an evacuation, and into building an ark out of a severed, immature Tube.
The Purple is a route code on a chart. The Amethyst Passage is the settlement's corrupted name for the same dead Tube, three centuries after anyone had reason to go there — a spoken name drifting while the written one stays put, surviving in a song and nowhere else.
Sixteen
Quick, serious, endlessly curious, impatient with the life laid out for her. Silver hair, emerald eyes, homespun orange and a glass lamp clipped to a battered harness.
Her only friend
Content with settlement life, and afraid of trouble. She covers for Pelsa's excursions and makes excuses not to come along.
The case for staying
The council voice against evacuation — the woman who loves the settlement too much to abandon it on a child's testimony. She loses that argument, and carries the evacuation out faithfully anyway.
The case for leaving
He counted the settlement himself last winter — twelve thousand nine hundred and forty, eleven days' work. Everyone else rounds. He knows exactly how many he is leaving behind.
