Freeman Dyson

Freeman John Dyson FRS was an English-American theoretical physicist and mathematician known for his work in quantum electrodynamics, solid-state physics, astronomy and nuclear engineering. He was professor emeritus in the Institute for Advanced Study in Princeton.

Dyson originated several concepts that bear his name, especially the Dyson sphere, a thought experiment that attempts to explain how a space-faring civilization would meet its energy requirements with a hypothetical megastructure that completely encompasses a star and captures a large percentage of its power output.

He proposed that trans-Neptunian objects, rather than planets, are the major potential habitat of life in space. Several hundred billion to trillion comet-like ice-rich bodies exist outside the orbit of Neptune, in the Kuiper belt and Inner and Outer Oort cloud. These may contain all the ingredients for life (water ice, ammonia, and carbon-rich compounds), including significant amounts of deuterium and helium-3. Colonists could live in the dwarf planet's icy crust or mantle, using fusion or geothermal heat and mining the soft-ice or liquid inner ocean for volatiles and minerals. Colonists of such bodies could also build rotating habitats or live in dug-out spaces and light them with fusion reactors for thousands to millions of years before moving on. Dyson and Carl Sagan envisioned that humanity could migrate to neighbouring star systems, which have similar clouds, by using natural objects as slow interstellar vessels with substantial natural resources; and that such interstellar colonies could also serve as way-stations for faster, smaller interstellar ships.