In 1997, Robert J. Bradbury proposed the matrioshka brain — a hypothetical megastructure of "immense computational capacity powered by a Dyson sphere." The name comes from matryoshka nesting dolls. The idea: wrap a star in multiple concentric Dyson spheres, each one computing with the waste heat of the sphere inside it.
The innermost shell runs at nearly the temperature of the star itself, processing at enormous speeds and radiating waste heat outward. The next shell captures that heat and computes with it, radiating its own waste heat to the shell beyond. Each layer runs cooler than the last, until the outermost shell operates near the temperature of interstellar space.
More shells means less wasted energy. Bradbury published the concept in the anthology Year Million: Science at the Far Edge of Knowledge. A related concept, the Jupiter brain, trades raw capacity for speed — it's planet-sized rather than star-sized, optimized for minimal signal delay rather than maximum energy capture.
Charles Stross used a matrioshka brain in his 2005 novel Accelerando to run simulated uploads of human minds. In the TV series Pantheon, an uploaded intelligence spends 16,807 years building one, then simulates billions of parallel universes over 101,000 years to resurrect her dead family.
Previously:
