On Tue, 28 Dec 2004 14:52:46 -0800, Roga wrote:
It is likely that, with efficient compression, alien radio data will be
indistiguishable from white noise. So, even if we can pick up the
radio communications, it is not likely that our current pattern-finding
algorithms will find much of a pattern at all. It will just look like
another star.

That's a problem only if we're intercepting broadcasts that they
intend for their internal consumption, and in that case chances
are they'd use a more focussed beam than we'd be likely to see.
If instead they're interested in communicating with people they
will use a means that they think people will be able to identify.

I don't know the answer to your primary question.
--
Jim Gillogly