[ExI] Scientists Find Solar System Like Ours

Jeff Davis jrd1415 at gmail.com
Mon Feb 18 21:55:43 UTC 2008


Several weeks back there was yet another delightful thread about the
Fermi Paradox.  It set me to thinking, among other things, about the
detectibility of distant civilizations.  About signal strength.  I
distilled the issue as follows: (1) Local omni-directional signals not
intended for interstellar communication -- local radio, tv, EMP from
nuclear explosions etc.; (2) Local directional signals not intended
for interstellar communication -- various directional radars for
example; and (3) Signals dedicated to interstellar communication
(assumed to be directional, as omni-directional makes no sense).

The strongest signals -- providing maximum detectability above
background noise -- seem available from honkin' big pulse transmitters
hooked to either a big dish or multiple big dishes; or a honkin' big
pulsed phased array; or the EMP from a nuclear explosion detonated at
the focus of a parabolic reflector.  Mostly from the standpoint of
size -- bigger is better, biggest is best -- of the transmission
assembly, it seems to me that the best results would be achieved in
the zero-g and atmosphere-free environment of space.

I will leave it to others to generate some numbers, but I would be
surprised if the range for such signals exceeded a few hundred light
years.  The distinctive signature of a nuke might be the strongest
signal, but I don't see how you could piggyback an information stream
on it.  It could announce one's presence and technical capability to
the maximum distance, but what else?  (Setting aside entirely the
issue of whether this is a good idea.)

Consequently, I found myself in sympathy with Kevin Freel's assertion
that we don't know what's out there. Because beyond some limited range
(a few hundred light years?) we're more or less blind.

Then this thread popped up, with it's microlensing amplification
theory-becomes-technique.  So I have to ask myself -- and you guys --
"Can microlensing provide a means of extending the communications
reach, of hearing/reading communication signals from further out among
the stars?"

Best, Jeff Davis

   "Everything's hard till you know how to do it."
                           Ray Charles

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