[ExI] Scientists Find Solar System Like Ours
pharos at gmail.com
Mon Feb 18 22:59:09 UTC 2008
On Feb 18, 2008 9:55 PM, Jeff Davis wrote:
> 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).
> 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?"
I doubt it.
Microlensing events are pretty rare and the magnification period only
lasts from a few hours to a couple of days. The effect depends on a
nearer star passing between us and a more distant star. Pretty rare,
as you can see. Planet-hunting astronomers therefore don't target
specific stars. They look for the event of a star passing in front of
another star anywhere in the sky, then analyse the further away star's
signals for the few hours available to them. If they are lucky they
The really long distance event I mentioned, uses whole *galaxies* for
the microlensing effect.
More information about the extropy-chat