Definition
Dyson Sphere is a hypothetical megastructure that completely surrounds a star to capture its entire energy output.
Why It Matters
It represents the theoretical limit of energy capture for Type II civilizations on the Kardashev scale.
Core Concepts
- Dyson Shell (Rigid): A monolithic shell. Extremely difficult to build; requires materials stronger than any known substance to resist gravity/buckling.
- How to read: “The value is approximately zero point seven seven grams per square meter.”
- Meaning: At this areal density, solar radiation pressure can balance gravity—a reflective sheet hovers stationary relative to the Sun instead of orbiting.
- O’Neill Cylinders: Rotating habitats inside or outside the sphere that provide artificial gravity and Earth-like ecosystems for biological humans.