It is an example of a Class B stellar engine, employing the entire energy output of a star to drive computer systems. The concept of a Matrioshka brain comes from the idea of using Dyson spheres to power an enormous, star-sized computer. The term originates from matryoshka dolls, which are wooden Russian nesting dolls. Matrioshka brains are composed of several Dyson spheres nested inside one another, the same way that matryoshka dolls are composed of multiple nested doll components. The innermost Dyson sphere of the Matrioshka brain would draw energy directly from the star it surrounds and give off large amounts of waste heat while computing at a high temperature. The next surrounding Dyson sphere would absorb this waste heat and use it for its computational purposes, all while giving off waste heat of its own. This heat would be absorbed by the next sphere, and so on, with each sphere giving off less heat than the one before it. For this reason, Matrioshka brains with more nested Dyson spheres would tend to be more efficient, as they would waste less heat energy. The inner shells could run at nearly the same temperature as the star itself, while the outer ones would be close to the temperature of interstellar space.
The engineering requirements and resources needed for this would be enormous. This could be used to simulate various cosmological structures:
|A brain||Asteroid brain. Based upon a computational substrate comparable in mass and size to an asteroid. Smaller than a moon brain.|
|M brain||Moon brain. Based upon a computational substrate comparable in mass and size to a small moon or rocky core of a planet.|
|P brain||Planetary brain. Based upon a computational substrate comparable in mass and size to a rocky planet.|
|J brain||Jovian brain. Based upon a computational substrate comparable in mass and size to a gas giant planet. A Betelgeuse brain is a Jupiter brain so large that it has to be supported by its own radiation pressure to avoid collapsing.|
|N brain||Neutron brain. Based upon a computational substrate comparable in mass, size, and density to a neutron star.|
|S brain||Star brain or Godstar. Based upon a computational substrate comparable in mass and size to the most massive stars, at minimum 10 solar masses. Matrioshka Brains are typically deployed around stars and are therefore S-brains. Cluster brains consist of many Star brains and/or Matrioshka nodes linked together by wormholes. The creation of a cluster is done with grazers and large mass sources such as large stars, nebulae, and brown dwarf bodies.|
|W brain||Wormhole brain. Based upon a computational substrate consisting of large numbers of entangled wormholes.|
|B brain||Black hole brain. Based upon a computational substrate composed of the Cauchy horizon of a black hole.|
|G brain||Galaxy brain. A hypothetical entity able to draw upon the processing power of an entire galaxy's mass.|
|U brain||Universe brain. A hypothetical entity capable of creating whole worlds. It's theorized that our universe is just the creation of a U brain.|
Matrioshka brains are way beyond yottascale computing:
- 1.12×1036 FLOPS is its estimated computational power, assuming 1.87×1026 Watt power (possibly solar) and 6 GFLOPS/Watt efficiency. This is for Type I prototypes.
- 4×1048 FLOPS is its estimated computational power where the power source is the Sun, with the ideal thermodynamic efficiency of a Carnot engine. This is for Type II.
- 5×1058 FLOPS is the estimated power of a galaxy used by Matrioshka brains. This is for Type III.