From: Tom McCabe (rocketjet314@yahoo.com)
Date: Wed Sep 05 2007 - 14:00:39 MDT
--- Adam Safron <asafron@gmail.com> wrote:
> Jeff,
>
> With regards to the missing heat, the outer layer of
> a matroishka
> brain
> (http://en.wikipedia.org/wiki/Matrioshka_brain)
> might be as
> cool as interstellar space. This seems more likely
> than hiding. If
> you can harness a billion light-years worth of
> galaxies, you don't
> need to hide.
True, but the energy output from a civilization that
large would be as clear as day on a CMBR map, even if
it is at 2.7 K. If that area contains a million
galaxies, each with a hundred billion stars, with
10^25 W/star, you get a total of 10^42 W of microwave
energy emitted. At ten billion LY away, the microwave
emission would be ~10^-11 W/m^2. The brightest sources
in radio astronomy are around 100 Janskys, which
equals 10^-15 W/m^2 (assuming uniform energy
distribution over a 1 GHz bandwidth).
> The appearance of a void
> gravitationally is more of a
> pickle, but could possible be explained by things
> like Shkadov
> thrusters:
> http://en.wikipedia.org/wiki/Stellar_engine. Your
> point
> about the time-scales of complex-life evolving is
> another pickle.
> However, you only need it to happen once to explain
> this particular
> void.
In order for thrusters to clear out a volume a billion
LY across in the history of the universe, they would
need to move the stars at .1 c, which is physically
impossible (even complete fusion of hydrogen will not
give it enough energy to accelerate to .1 c).
> Most likely, it's just a big void and the
> exponentially expanding
> intelligence (EEI) speculations are wrong in this
> case. If
> gravitational lumpiness ends up being the best
> explanation for this
> void, then it may be more parsimonious to assume
> that it is the best
> explanation for other voids as well. Though it is
> still possible
> that there are more than one type of void, evidence
> is needed to
> support EEI theory.
>
> So Fermi's paradox may not have been solved by EEI
> theory of voids.
> Too bad. In my opinion, it seemed like a good
> contender. For a
> complex intelligence, the most reasonable thing
> seems to be to expand
> outwards and try to harness as many stars as
> possible for driving
> computation. Even under the conservative assumption
> that recursively
> improving AI is achieved once only every couple
> 100-1000 galaxies, we
> should be able to explain interstellar voids and
> Fermi's paradox. If
> EEI theory is wrong, then there are several
> different possible
> implications, which are also reasonable:
> 1. Complex intelligence evolves very rarely; much
> less than one in
> a thousand galaxies.
> 2. The evolution of complex intelligence does not
> imply the
> creation of recursively improving AI; perhaps the
> civilization is
> destroyed before obtaining that technological
> achievement.
> 3. Even assuming recursively improving AI, stellar
> engines are
> unfeasible (not enough mass in the solar systems; no
> way of
> controlling star dynamics) or undesirable
> (super-intelligences
> thought of something better).
> 4. Evidence for simulation (less reasonable)?
> Something else?
>
> Doesn't look good for EEI theory... Case closed
> pending further
> evidence.
>
> Thanks for the discussion.
> -adam
>
> On Aug 24, 2007, at 10:15 PM, Jeff L Jones wrote:
>
> > On 8/24/07, Adam Safron <asafron@gmail.com> wrote:
> >> If we are now seeing the light from 6-10 billion
> years ago, then how
> >> can we be sure the void isn't (still) expanding?
> >
> > That's a good point. I think you're right, that
> we can't really tell
> > whether the void is still expanding (as long as
> it's expanding slower
> > than lightspeed). So I take my rhetorical
> question about "why would
> > it have stopped?" For some reason, I didn't think
> of that when I
> > wrote that.
> >
> > But the other two issues still seem puzzling. How
> any sort of
> > intelligence would have developed that early on
> (3-7 billion years
> > after the big bang, when it took 4.5 billion years
> on earth... and the
> > universe looked very different and less
> life-friendly back then). And
> > if they're living there but hiding... how they
> could unbend the light
> > passing through in such a way that it looks like
> there is no
> > gravitational disturbance there. Another question
> is how/why they are
> > cooling the cosmic background radiation as it
> passes through, but that
> > actually seems to have a rather simple answer in
> the context of
> > superhuman intelligence... they could be
> harvesting energy from the
> > cosmic background radiation too (perhaps large
> antennas set up to
> > collect it?) If there's a way to do that
> technologically, it might
> > provide them with even more energy than they could
> get out of the
> > stars! (Just speculating here). But the only way
> to explain why the
> > amount of cooling happens to be exactly what you'd
> expect if there
> > were nothing there is that they are deliberately
> trying to trick
> > outside observers into thinking there's nothing
> there. So the
> > question still is... why do they go through all
> that trouble to hide?
> >
> > Jeff
>
>
- Tom
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