The Record
Why the Vigil's heat needs dozens of Earths of radiating surface, and what that makes of its rank on the Kardashev scale.
Why is the biggest part of the swarm the one you cannot see?
Computing makes heat, and in space heat can only leave as light. The Vigil's films are the surfaces that do it. Each one is about a kilometre across and black in visible light, so Ember's glare passes into it and nothing comes back design. Their own glow is at 30 K, which is far into the infrared, so in the sim's visible mode the corridor between them reads as black faces with one bright line at each edge.
The films are held edge-on to Ember for a reason. At Vesper's distance Ember's light delivers 2,152 times what a 30 K film emits, so a film that faced the star would heat up instead of cooling. Tilted by more than 0.46 milliradians, a film takes in as much starlight as it sheds physics. Every film therefore points its edge at Ember, and the sim shows that by flying down a corridor of them.
One petawatt of heat at that temperature needs 43 Earths of radiating surface physics. Power is cheap, because a trickle of matter into a black hole makes a petawatt, but cooling is the economy. That is the chapter's second beat, an infrared view that shows the films' own glow.
The chapter then runs ahead of the Record. At the plan's goal of 1 × 1020 W, reached in 2553, the radiating surface would cover about 4,300,000 Earths simulation. A civilization's rank on the Kardashev scale follows its power. The swarm in 2540 sits at 0.9, and the plan's goal is 1.4. At the goal the films would close into a shell with a radius of about 0.088 AU simulation. The last beat zooms out from one node to the swarm, the local stars and the galaxy, labelling the power at each level. The chapter's argument is that radiators, not power plants, set a civilization's level, and its two toys let the visitor tilt a film against Ember and trade a radiator's temperature against its area.
Which numbers does this chapter rest on?
| What | Value | Basis |
|---|---|---|
| Film temperature | 30 K | design |
| Ember's flux at Vesper over a cold film's emission | 2,152 | physics |
| Tilt at which starlight in equals heat out | 0.46 mrad | physics |
| Radiating surface for one petawatt | 43 Earths | physics |
| Power at First Light | 1 × 1015 W, 0.9 on the Kardashev scale | fiction |
| Plan's goal | 1 × 1020 W, 1.4 on the Kardashev scale | simulation |
| Radiating surface at the goal | 4,300,000 Earths | simulation |
The reasoning behind the emission area and the cold temperature is in Cooling is the economy. The outer edge of the radiator band is the one tight constraint on the layout, and Where you can live around a hole and a star shows where it comes from. Why a civilization is better ranked by what it controls at small scales than by the power it burns is in Inward, not outward.
Play it, or go there
Play this chapter 1:45, narrated, with the same numbers as this page.