Places
Five bands of machinery, each placed by the one physical reason it cannot go anywhere else.
How big is the swarm, and where is everything?
The swarm is machinery spread over the space around Vesper. Its First Light radiator-material target is 1.1 × 1014 kg in 2540, built by 37 doublings from a one-tonne seed fiction challenge. The plan's goal is 1.1 × 1019 kg, reached in 2553 at the same pace simulation challenge. The zones run from the hole out to 12 AU:
The film mass and replication target use the assumed 0.01 kg/m² cold-film density. This is an unsourced engineering target challenge; Cooling is the economy separates that assumption from the physical area law.
| Zone | Distance (AU) | Holds |
|---|---|---|
| A, the Engine | to 0.05 | feed streams and the minidisk |
| B | 0.05 to 0.1 | light collectors, facing Ember |
| C | 0.1 to 0.4 | computing nodes |
| D | 0.2 to 0.6 | radiator films and heat engines |
| E, the Ashfall | 4 to 12 | mining and yards |
Why does each band sit where it does?
A is where the matter goes in. B is right outside it. Its collectors face Ember, not the disk: at First Light the disk's whole petawatt is a millionth of a watt on each square metre there, and Ember's light is 99 W/m². The petawatt takes 8.9 × 107 dishes and the goal takes 8.9 × 1012 design. The disk's own light goes to a small ring of dishes much closer in, in zone A, the Engine.
C holds the computers, and light time sets its size. A signal from Vesper to zone C takes 50 to 200 seconds, and a signal across the zone takes 6.7 minutes, which gives a round trip of 13 minutes physics. A mind spread across the zone cannot synchronize a thought faster than that, which is the argument of Big minds are slow minds.
D is where the heat leaves. One petawatt of heat at 30 K needs 43 Earths of radiating surface. The films glow from both faces, so they cover 21 Earths, and they take the most room. A film facing Ember would take in 99 W/m², 2,152 times what it sheds, so every film is turned edge-on. A tilt of 0.46 milliradians is enough to let in as much starlight as the film sheds physics. At the plan's goal of 1 × 1020 W the films would cover 2.2 × 1021 m², which is a closed shell of radius 0.088 AU simulation.
The outer edge of D is the one tight constraint. Orbits around Vesper are stable out to 0.66 AU, and D reaches 0.90 of that, because Ember's pull wins beyond it physics. This bound is a fit extrapolated below the range it was fitted in, with an error of up to 11 percent; direct integration of this system put it at 1.01 times the fit design.
E, the Ashfall, sits outside the unstable region for orbits around the pair, which reaches 2.9 AU by direct integration physics. It is the only band that circles both bodies instead of one.
What does it teach?
The stable-orbit sums are in Where you can live around a hole and a star. The reason the films dwarf every other band is in Cooling is the economy. How the whole machine doubled to its size is in Doubling. The computing nodes in C, where residents run, are on their own page.