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Whistler Smother

  [vote for,

It occurs to me that Whistlers, whilst very interesting in their own fashion, are also a form of reasonably likely detectable space emission that the Earth produces on an ongoing basis (then offgoing, in between the ons).

How about we invent a means of, well, not nullifying the generation of whistlers themselves, but a way of covering them in some kind of radio blanket, to veil their presence. If we can do that with a controllable periodicity, we might be able to transmit binary on-off signals to those aliens out there.

(Oh, as it is 4th of May, happy Star Trek day).

Ian Tindale, May 04 2018

https://en.m.wikipe...ki/Whistler_(radio) [Ian Tindale, May 04 2018]

http://zebu.uoregon.../images/barnard.gif [2 fries shy of a happy meal, May 05 2018]

Earth's radio brightness https://groups.goog...T1fT94/mSoOHGg8GBQJ
I read about this a whole lot of years ago. Perhaps I should have specified "certain frequencies only" since the Earth is not so bright in various other radio frequencies, than those used by radars. [Vernon, May 06 2018]

Sorry, https://en.m.wikipe...Whistler%27s_Mother
I only just got the joke. [pertinax, May 09 2018]


       I could be wrong about this (and since this is the Internet, I probably am) but:   

       Whistlers are echoes of the impulses caused by lightning.   

       The electromagnetic pulses from lightning bolts radiate out from the earth's surface and curve around, in paths that follow the planet's magnetic field, eventually coming back to hit different points on the surface.   

       The channel is dispersive - higher frequency components travel more quickly than lower frequencies - and so the initial momentary "crack" of the lightning spreads out into a gradually descending "whistle", sorta like chromatography for RF.   

       Very little of the emitted energy escapes the planet entirely.   

       Veiling them is pointless, because nobody else can hear them, and even if they can, they'll just sound normal for a planet like ours. If anything, they might be conspicuous by their absence.
Wrongfellow, May 04 2018

       Due to things like military radars, Earth is actually already the brightest radio-energy source in this part of the Galaxy.
Vernon, May 05 2018

       //Earth is actually already the brightest radio-energy source in this part of the Galaxy.//   

       Is that true? Depending on your definition of "this part", there would be huge numbers of stars of all sorts, as well as planets similar to Jupiter spewing out radio noise. You may be right, but do you have a citation for that?
MaxwellBuchanan, May 05 2018

       Are you including the sun?
Ian Tindale, May 05 2018

       A while ago I read about a concept called the "temperature spectrum" of the planet.   

       The basic idea is, for any frequency interval 'f' to 'f + delta', look at the total energy radiated by the planet in that frequency band, and work out the temperature it would have to be at to radiate that energy if it were a pure black-body.   

       Let 'delta' become small and plot the result on a graph against 'f'.   

       If the Earth really was a black body, the graph would be flat, and would show its actual temperature. Since it's not, the graph wiggles up and down.   

       If I'm remembering correctly, the Earth's "apparent temperature" in the radio and microwave bands is enormous, due to artificial radio transmissions. This was proposed as a way to look for evidence of intelligent life on other worlds. Maybe this is what [Vernon] is referring to?   

       Unfortunately I can't find a link to share; Google's just giving me climate research stuff. I'm probably using the wrong search terms.
Wrongfellow, May 05 2018

Earth's spectral signature. Here is a graph of our output as seen from Barnard's star located about 13 light years away. [link]

       This information could apparently be used to determine rotation rate, distribution of land masses, population growth, and just how brokeback our mountains are.   


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