Classification of civilization types according to energy usage.
Type I civilizations control all available energy on a single planet.
Type II civilizations control all available energy in a solar system (for example, using Dyson spheres).
Type III civilizations control use all available energy in an entire galaxy.
Type IV civilization controls all available energy in the entire universe. The Terragen bubble is currently moving towards a Type III civilization, but this will not be achieved for at least another 100,000 years.