An interesting note  on /. this morning  citing an actual web site  about the Nemesis theory  started me thinking about whether or not Nemesis could be a Matrioshka Brain .<br><br>If so, that opens a whole range of possible thought paths regarding the superintelligent design and/or management of our solar system...
<br><br>Is there any hard evidence *against* Nemesis other than the fact that we haven't located it? True, we haven't discovered it using past surveys, the best of which, at least for IR, was probably IRAS, but its frequency detection was not that far into the IR and its resolution certainly wasn't very high. But if we are *still* discovering nearby planetary bodies,
e.g. Sedna, 2003UB313, etc. then we cannot have done very robust surveys. The initial Nemesis proposal (according to Wikipedia) seems to be for a Mag. 7-12 red dwarf most likely at 1000+AU(?) -- but those calculations would have a much wider range if one was dealing with a "dark" object such as a Matrioshka Brain).
<br><br>If you don't like the small star powered Matrioska Brain idea, how about a swarm of of them powered by internal fusion reactors, masquerading as Oort cloud bodies? They could still accomplish the gravitational disruption of the Oort cloud at periodic intervals (a key element of the Nemesis theory) and use their Oort cloud encounters as refueling opportunities. One could also ask if we have done *enough* occultation astronomy (
i.e. we would have to watch the *entire* sky semi-continuously for disappearing stars) to notice *really* large (gas-giant planet to star sized?) solar arrays collecting the low density solar radiation at 100+ AU to supply power to numerous Jupiter Brains. Muller's comments  lead me to believe we aren't even close setting constraints on "alternative" explanations for Nemesis.
<br><br>Once again, astronomers trip over the assumption that the universe must be "dead". :-(<br><br>Robert<br><br>1. <a href="http://science.slashdot.org/article.pl?sid=06/01/21/0338234">http://science.slashdot.org/article.pl?sid=06/01/21/0338234
</a><br>2. <a href="http://www.binaryresearchinstitute.org.nyud.net:8090/">http://www.binaryresearchinstitute.org.nyud.net:8090/</a><br>3. <a href="http://en.wikipedia.org/wiki/Nemesis_%28star%29">http://en.wikipedia.org/wiki/Nemesis_%28star%29
</a><br>4. <a href="http://en.wikipedia.org/wiki/Matrioshka_Brain">http://en.wikipedia.org/wiki/Matrioshka_Brain</a><br>5. <a href="http://muller.lbl.gov/pages/lbl-nem.htm">http://muller.lbl.gov/pages/lbl-nem.htm</a><br><br>