In article <e209b9f9.0402040544.3b6ea66e@posting.google.com>, Keith
Watson <kpwatson@luna.co.uk> writes

Doesn't that assume that all technologically
based cultures always use a specific part of the electro-magnetic
spectrum to communicate, etc.?"

Yes

It did get me thinking though. Although our current technologies use
electro-magnetic waves for communicating (i.e. radio, television,
radar, etc.) are we justified in assuming that we will always use
this? and by inference assume that extra-terrestrial intelligences
(ETIs) will also?

Yes

This basic assumption you point out is compounded by other issues -

1.      That they are technologically based (like humans)
2.      That the technology used is similar to our current ones
3.      That there is no other technological approach available at
        present (like mind contacts, etc)
4.      That the accelerating progress of technology places them
        within + and - 100 years of our current position
        NOTE:   If we listened to ourselves 100 years ago our
                ancestors would not be able to receive us.
                If we listen to ourselves in 100 years time, would
                we be able to communicate with these humans?

IS ET OUT THERE?

I think life on other planets is alive and well, under the right
conditions. 

The Drake equation would give some probabilities. 

Within these planets with life there will be a significantly decreasing
probability of intelligent life. More importantly, there is a serious
doubt about this on earth just now, with the way we behave one to
another at an individual and nation level.

Finally, there is a further significant decrease in the probability
those intelligent life ETI have taken a technologically based approach
like humans?

I would like to comment that the main reason, as I understand it, for
listening at the 1.419 ... (etc) Ghz hydrogen spectrum is this is a
"quiet zone", and has a potential for being used by ET?? Moreover, it is
at a frequency that is less likely to be attenuated/absorbed by the
distances involved (yes or no ??)
-- 
John Clark

In the "reply to", replace either "fredclark" or "Workgroup" with 
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