In talk.origins Robert Carnegie <rja.carnegie@excite.com> wrote:

On Aug 17, 10:50 pm, Paul J Gans <g...@panix.com> wrote:

In talk.origins Tiny Bulcher <alycid...@btinternet.com> wrote:

?us cw?? Chris L Peterson:

On Sat, 16 Aug 2008 22:16:27 -0500, Charlie Siegrist
<none.act...@this.time.check.back.later> wrote:

On Sat, 16 Aug 2008 19:31:07 +0000, Paul J Gans wrote:

Because the radio age *here* will last only about 200 years, if
that.

I don't see why.  As fiber-optic communication spreads, microwave
point- to-point is tending to decrease, but cell phone and other
personal radio communication devices are proliferating at a strong
rate.

Certainly, there is no reason to think we'll stop using radio. As you
note, its use will increase. But the sort of radio we use will not
make us radio bright. It is reasonable to think that technological
civilizations would only be detectable by their waste radio emission
for a short time. Radio remains an obvious candidate for any
civilization that deliberately wants to make itself known, however.

I thought Paul was alluding to the possible brevity of an
advanced-technology human civilisation.

Not in the sense of self-destruction.  Already much of what
used to be broadcast by high powered radio stations is now
carried via pipes, mostly fiber optic ones.

And, as I've already answered, radio as an obvious source of
interstellar contact is a notion that depends on our particular
mix of senses and technology.  There's no need for other forms
of life to have the same set.

Radio communication started out as a wireless version of the telegraph
signal, dots and dashes.  That's likely to be useful independent of
your senses, and likely to be discovered by any aliens who use
electricity for a while.  I myself have accidentally  observed in
favourable conditions a small electric spark inside my umbrella-frame
not especially close to high-voltage overhead power lines for railway
trains, so only cultures whose planetary atmosphere is thereby made to
explode won't be heard from.  (Obviously, these are planets that also
don't have lightning.)

Sure.  And we get radio signals from Jupiter too.  Random and 
noiselike sources don't get you anywhere.  And many natural
phenomena generate non-random signals.  Lightning is an example.

Radio happens to be the first major technology that has even
the possibility of interstellar communication.  That's why so
many here love it.  But many here are also ignoring new techniques
yet to come.  And many are ignoring that other beings might have
sensory systems attuned to different phenomena.

A thousand years from now even we humans might think of interstellar
radio communication as being about as good as lighting large bonfires.


-- 
   --- Paul J. Gans