These pages apply the physics to questions about civilizations, self-replicating machines and software minds. They identify the assumptions behind each proposal and the questions that remain unresolved.
Civilizations are usually ranked by how much power they use. Earth in 2026 is at 0.73 on that scale, the Vigil's first petawatt puts it at 0.9 in 2540, its plan aims for 1.4 in the 2550s, and the whole Milky Way is at 3.2. The Vigil prioritizes finer control of matter and lower energy use per computation before expanding its power supply.
Where should I start?
Start with inward, not outward. It sets two ladders side by side, one counting power and one counting the smallest things a civilization controls, and it is the thesis of the whole site.
Then doubling, the other half of how the Vigil got going. A machine that makes copies of itself turns a 1,000 kg seed into 1 × 1014 kg of radiator in 37 doublings.
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.
Copy, merge, choose your clock examines residents that are programs, the resources they would need and the unresolved questions about identity and consciousness.
The last two look at time. Thinking in a cooling universe follows the cost of a thought as the universe cools, to a floor at 2.2 × 10−30 K. Why they might be asleep asks whether a patient civilization would just wait for the cold, and what that would say about the silence in the sky.
Where does it lead?
Every idea on these pages comes from a number somewhere else. The limits strand holds the floor under the cost of thought, and the heat strand holds the radiators that make the Vigil's size what it is.