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Re: RE: starship-design: It's a bad, bad world out there
In a message dated 10/27/97 11:31:55 PM, email@example.com wrote:
>> From: Kyle R. Mcallister[SMTP:firstname.lastname@example.org]
>> David Levine wrote:
>> > Is this necessarily true?
>> > Ref.:
>> > http://www.landfield.com/faqs/astronomy/faq/part6/section-13.html
>> > How far away could we detect radio transmissions?
>> > The idea behind this part of the sci.astronomy FAQ is that detection
>> > normal radio and television signals at interstellar distances is a
>> > Math is included. One summary quote:
>> > "Even a 3000 meter diameter Radio Telescope could not detect the 'I
>> > Lucy' TV show (re-runs) at a distance of 0.01 Light-Years!"
>> Yes, it is true. Unfortunately they can't hear TV shows without BIG
>> radio arrays. Or is that fortunate...?
>Actually, I was asking if Kelly's assumption that a power grid like ours
>would be detectable at interstellar distances, not if the quote from the
>FAQ was true.
>> Well, that depends on what kind of power grid you're speaking of. Low
>> tech would be virtually undetectible. Mid level, like us VERY
>> detectible. High tech may be either blaringly loud, or more likely
>> silent. Or it could account for some of the IR emmisions we've
>Well, this is what I mean - assuming that very highly advanced
>civilizations would contain their power leakage (it's a waste, for one
>thing) then we're only talking about civilizations like us. I'd like to
>know - are you and Kelly both assuming it would be detectable? Or do
>you guys have figures to back it up?
>WHY is the Earth's power grid detectable from, say, Tau Ceti?
>Narrowband radar I'll agree to - I've seen the numbers. But I'd like to
>see numbers on how much EM radiation our power supplies leak.
You have to remember, the whole continental power grid is syncronized and
pulsing at 60 cycles per secound, with trillions of watts of power flowing
through it. Other EM sources lack the power, but are in frequencies that
little else is in. One quote I remember was that earth out shines the sun in
certain EM bands. Anyone interested in looking should have little
difficulting seeing Earth em glow (and wouldn't limit themselves to a little
3,000 meter scope).