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WB6YRU > SETI 06.12.04 11:40l 62 Lines 2703 Bytes #-7101 (0) @ WW
BID : 14784_N0ARY
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Subj: Re: SETI...WB6YRU and KB2VXA
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Sent: 041206/0811z @:N0ARY.#NCA.CA.USA.NOAM #:14784 San Jose, CA $:14784_N0ARY
Ralph VK1ZRG wrote:
> what if everyone is listening?
That would be a bummer, wouldn't it? :)
> I have a vague recollection that some transmissions were made
> from Arecibo many years ago, but were discontinued because it was thought
> prudent not to advertise our existence on Earth.
I've heard that bogus argument too. But we are! Maybe not
intentionally, but we've been sending out signals for decades.
We may not be capable of receiving our own TV and radio signals
at the nearest star (Apha Centari), but someone else might.
We're also sending out radar and the occasional transmission to
deep space probes. Those are much more beacon-like than
broadcast transmissions.
> I'm not quite sure what you mean by "next generation of receivers".
> In terms of sensitivity or system noise temperature, they are NOT going to
> get very much better than they now are.
It's hard to say what new inventions, techniques, or discoveries
we might come up with in the future. I think it's pretty
arrogant to say we can't do much better than what we have now.
Look how far we've come in just the past few decades. Are you
saying that's it, even centuries from now there's nothing more
we can do to improve signal to noise or sensitivity? You don't
know that. Whose to say some new technique or discovery won't
or can't be made that will be a significant improvement?
Based on how far we've come over the past century and how much
we still don't know, it's inconceivable we've already hit the
upper limits of receiver technology.
> I know a fair amount about this subject, having worked in the Department
> of Astrophysics at the University of Sydney, for 10 years before my
> retirement. During that time we totally replaced all the receiving equipment
> and local oscillator system for the Molonglo Observatory Synthesis Telescope,
Pray tell, why were they replacing all that equipment? And
with what? Something "significantly better," perhaps? ;)
> For SETI, the name of the game is square metres of collecting area.
Of course. Even if you're right about our receivers, there's
always the possibility of very large antennas on the far side
of the Moon or in space. I'm talking now of antennas *many*
kilometers wide.
We could even make some discovery that allows us to manipulate
electromagnetic radiation on planetary scales, or more. Of
course I can't say what that might be, we're still stuck here
near the beginning of the primitive 21st century. ;)
We've only been at this radio stuff for a mere 100 years or
so. And this is all assuming ET hasn't moved on to something
way better than radio waves.
73, Gary WB6YRU, sysop of N0ARY.#NCA.CA.USA.NOAM (San Jose, CA)
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