--- On Fri, 7/16/10, Jed Rothwell <jedrothw...@gmail.com> wrote:
Jed, and all:
Another I'd add to the list is, we assume they would use radio waves or optical
(laser) communication (ala COSETI). Some other medium may exist, which we
either cannot use effectively at the moment (neutrinos) or which we don't know
about at all. If faster than light communication is possible, they wouldn't
worry with something as slow as radio. Perhaps there is a window of time in the
development of intelligent, communicative civilizations in which they are only
broadcasting radio waves for a brief time before something else is used. Or
they may not broadcast deliberately at all. We know of one civilization that
very, very rarely does: humanity.
> 1. Recent studies have shown that transmissions from earth are probably > too
> weak and scrambled to be decoded after a few light years. I don't
> know the basis, but that's what I have read. It is a myth that people on >
> other planets could hear our radio and TV broadcasts, or signals from
> our space probes. So unless the alien civilization is deliberately
> broadcasting for an interstellar audience we will not pick it up.
TV and commercial radio broadcasts would reach out a light year or so before
being 'lost.' They would have to, barring some better technology, send a probe
on a flyby of the solar system to eavesdrop. On the other hand, military and
planetary radar -can- reach out a great distance. Should an intelligent
civilization be predisposed (read: curious and perhaps aggressively
expansionistic), they could look for telltale signs of this sort of thing going
on in the local group of stars. Someone a dozen or so light-years away could
have arrays of radio telescopes looking at all nearby stars which could
conceivably support life and a civilization, listening nonstop for the first
hint of something going on. If they are advanced enough to do this, one would
think their signals-processing technology would be that much better. A few
picked up radar sweeps might intrigue them. Whether or not that would be good
is arguable.
--Kyle
