Re: SETI is pointless

Ian,

Haha - the more I talk with people the more I am struck by the fact
that regardless of what is said, they will hear only those things that
let them to continue an argument, even when it is clear there is no
basis for an argument.

lol.

This is the fifth time I've said this here -

I have not left out bandwidth.

I have fully understood the impact long distance signalling HAS on
bandwidth.

You have not -

So please listen closely; since I have said it in every post I've made
- and I will say it one more time here;

* * * *

Yes, the bandwidth of light as a carrier wave is superior to the
bandwidth of microwaves as a carrier wave- . No problem.

Yes you can see light - of any frequency - completely around the
universe - whether its a QUASAR at the 'edge' of the universe, or the
3K microwave background - no difference - and again no problem.

But get this -

at low carrier frequencies, you start getting interference from
thermal effects in plasma, gas clouds, star surfaces, and so forth
that degrade signals with distance.

AT HIGH CARRIER WAVE FREQUENCIES (light) OVER VERY LONG DISTANCES YOU
HAVE QUANTUM EFFECTS THAT DESTROY MODULATED SIGNALS.

Got it?

That's why OSETI uses signalling rates of less than 1GHZ despite the
high freuqncies of carrier waves.

That's the meaning of this chart

http://shayol.bartol.udel.edu/~rhdt/diploma/lecture_12

See the line that starts on the right and continues to rise with
frequency?

The one calle QUANTUM LIMIT?

Yep, its a function of FREQUENCY!

The best we're likely to do in terms of bandwidth is 100GHz - maybe
300GHz with fancy coding when we're at both sides of the signal beam.

.

Relevant Pages

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