You know, I've never really thought about those big planets being brains of some sorts. This is really not my expertize, but a reason that these civilizations might have went with this design is that, due to the light cone, it was the best mechanism to maintain conscious coherence. Perhaps there are some cooling issues here, to. Spin the brain so that only part of it is actually soaking up sunlight and storing it, while the other part is pointed into space. Just some thoughts.
>"Robert J. Bradbury" <bradbury@www.aeiveos.com> writes:
>
>> While I've devoted some thought to whether the observed "planets"
>> could be supercomputers (like the old Jupiter Brians idea), I
>> can't come up with a good reason why a civilization would waste
>> most of the energy the star generates. At the Extro4 conference,
>> Anders indicated that he has an updated version of his J-Brain
>> paper that adds some additional classifications & structures for
>> the supercomputers/SIs, but I don't think these help much.
>
>The only reason I can think of would be that they don't care - you
>build computing structures out of all the available matter, and the
>energy requirements tturn out to be less than the entire stellar
>output. Might happen if people settle for my 'Zeus' model of
>megastructures (cold diamondoid planet-sized system), but I better do
>some calculations on how to maximize the information
>content/production in the entire system.
>
>
>> During a coffee break, I overheard two young scientists from NASA Ames &
>> The SETI Inst. discussing "I don't understand the comment about
dismantling
>> Mercury...". So I stopped and did a brief explanation about molecular
>> disassembly, exponetial growth, etc. When I got through, they had no
>> "scientific" objections as far as I could determine. At least one
however
>> seemed very concerned that the astrologers would never allow me to
>> dismantle Mercury since it would cause a signficant amount of disruption
>> to their frame of reference.
>
>Hurray! Hmm, maybe we should as posthumans just rearrange the solar
>system to "improve" on astrology? :-)
>
>-----------------------------------------------------------------------
>Anders Sandberg Towards Ascension!
>asa@nada.kth.se http://www.nada.kth.se/~asa/
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>