Matrioshka Brain Home Page

Robert J. Bradbury

A Matrioshka Brain is a megascale structure constructed at atomic scale limits.  It is essentially a Dyson Shell supercomputer, that uses all of the energy a star produces and all of the material in a solar system for "computronium".  Because of their size, immense observational and computational abilities, Matrioshka Brains should have longevities at least as long as those of stars (~1014 years for smaller stars).

Whether or not Matrioshka Brains or similar structures exist in our galaxy currently is presently unknown.  As discussed in the papers below, the astronomical evidence lies someplace between provocative and suggestive.  Even should they not currently exist, they are worthy of further study because it is likely that humans will possess the technological capability of building one in our solar system or around nearby stars within the next century.

Some may ask how does a Matrioshka Brain differ from a Dyson Shell?  The answer is that the original concept, as envisioned by Freeman Dyson, was a single layer of habitats for human beings orbiting the Sun between the orbits of Mars and Jupiter.  Given the material requirements of "habitats" it is possible that a civilization may be required to construct them in such a way that the star they surround would remain visible.  (This may be why anthropocentric SETI searches for Dyson Shells point their telescopes and radio receivers at visible stars.  Alternatively this may just be a problem that insufficient thought has been devoted to the evolution of technological civilizations.)  A Matrioshka Brain, in contrast to a Dyson Shell, is a set of nested shells (like the nested Russian Matryoshka Dolls) that surrounds a star most likely from orbits that would range from inside Mercury's to outside Neptune's in our solar system.  The material requirements of its computronium are sufficiently low that there is nothing to prevent the civilization from completely harvesting all of the more useful energy produced by the star resulting in it being essentially invisible at visible wavelengths.  The computronium would support advanced technological civilizations whose thought architectures and capabilities go far [really far(!)] beyond those found in  human brains and humanity as they currently exist.

One way to think about Matrioshka Brains is to ask the question, "What is the highest capacity thought machine (computer) that can be constructed using the smallest scale technology (e.g. molecular nanotechnology) within a solar system?"  The basis for discussing Matrioshka Brains is to adhere to generally accepted laws of physics and forego the invention of new laws (something that is required for some lines of thought in Science Fiction).

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Created: Circa 1998
Last Modified: August 16, 2004
Author: Robert J. Bradbury