As the term Jupiter Brain originated primarily as an identifier for a megascale ultraintelligent machine and at the time there was little thought was put into its actual acrchitecture. The first known scientific exploration of the physics of these machines was an essay titled, "The Physics of Information Processing Superobjects: Daily Life Among the Jupiter Brains", written by Anders Sandberg in July 1997. Robert Bradbury presented some ideas on Jupiter Brain structures during his talk, "Paths to Immortality" at the Extropy 3 conference on August 10, 1997. During 1998 and 1999, these ideas were extended by Robert with actual engineering models. Because Jupiter Brain architectures generally fail to make optimal use of the engineering materials and energy resources of solar systems, he invented an alternate architecture - a Matrioshka Brain (MB), after the nesting Russian Matrioska Dolls, to better describe one optimal computing structure. These structures and some of their qualities are discussed in his paper about Matrioshka Brains. These ideas were presented, though not widely viewed, in a poster (Abstract: PS/PDF)at the Bioastronomy 99 conference on August 2 & 3, 1999. During conversations at the Extropy 4 conference, Anders indicated to Robert that his original paper had been updated to include some architectural information and had been submitted for publication in the Journal of Evolution and Technology (see Volume 5).
A JB (the size of Jupiter, in Jupiter's orbit), receives approximately ~1018 Watts of solar energy, enough to power ~1013 Drexler style nanocomputers (~1017 human brain equivalents). At this level, a JB is a Kardashev Type I+ civilization. A MB would consist of ~1021 nanocomputers (~1025 human brain equivalents) and is a Kardashev Type II civilization. MB computational capacity is 100 million times JB thought capacity. A MB represents one logical end point for the evolution of advanced technological species. MBs communicating over long time scales may form a Galaxy Brain, also known as a Kardashev Type III civilization. JBs and MBs are very large scale entities, with volumes ranging from that of a small planet to that of a solar system. Their observational capabilities (~109 telescopes the diameter of the moon); thought capacities (~1042 operations per second); and energy and mass resource management (those of entire solar systems) would allow them to monitor the galaxy, predict potential cataclysms and prevent or avoid the negative impacts of such hazards. Because they can effectivly control their galactic hazard function (as humans do now to a significant degree with their terrestrial hazard function) their longevities are likely to range from tens of billions to trillions of years..
There is some relationship between MB, JB and Dyson spheres/shells and Niven Rings. Some background for these ideas and some comments by H. Keith Henson can be found on pages 210-214 in the Great Mambo Chicken & The Transhuman Condition by Ed. Regis (1990).
Jupiter Brains are also know as Betelgeuse brains, Andromeda brains, megaminds, superintelligences and intelligent superobjects.
Note: as of August 1999, some of the links above may not allow access due to insufficient clarity regarding copyrights on the web. If you have a strong need to access these sources you can contact Robert Bradbury and request access permission.
On December 23, 2003 an email was received from Keith Henson indicating that he believed that the initial exchange regarding computers the size of Jupiter took place on the private Extropians list between Perry E. Metzger and David Kreiger in September of 1991.