On Sun, 17 Aug 2008 21:43:59 +0000 (UTC), Paul J Gans <gans@panix.com>
wrote:

Obvious to *us*, not necessarily to others.

What we think of as simple happens to depend on our particular
mix of sensory apparatus and technological development.  These
particular traits might not be shared.

Of course. You can always postulate some really obscure physical basis
for intelligent life, or some really different sort of intelligence.
IMO, however, talking here about the development of _technological_
intelligence, it is very reasonable to consider that any species would
consider radio a very good candidate for interstellar communication. It
has excellent range, is easily controlled and easily received. Almost
any technological species is likely to have the capacity to recognize
encoded radio signals.

I think we have a pretty good understanding of how the Universe works,
and I doubt there are a lot of communication methods we haven't thought
of. Some of them are a bit beyond our current engineering skills (but
not much). While there are certainly other methods that could be used
(neutrinos, gravity waves, light), radio remains a very reasonable place
to concentrate our current SETI efforts, for the simple reason that it's
a very reasonable choice for an alien communicator to use.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com