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Index of Subjects Hi Dave, others... I think the main conclusion I had on this topic is to try to resist the temptation to try and "think it through", not possible, and instead recognize that it's a problem of insufficient data. Feels like there is something out there, but neither the existing data nor the explanations are at all conclusive. It will probably take someone working regularly way up north who happens to be making radio frequency measurements professionally and who also has a synchronized video recorder pointing upwards, plus an array of microphones and a multichannel recorder in some nearby stunted pine forest (sharp needles), also sync'd. Could be a while before this happens. The latest issue of Nature, 2 Nov, reports the difficulties a half-constructed new SETI array is having keeping its funding, a project with a much more attractive public profile. Talking about stargazing, I spent about 30 min off and on peering through the occasional breaks in the clouds for Leonid meteorites 1-2 AM Sunday but didn't see any. Was anyone successful? Closer to the ground, I've never seen so many winter moths as this year -- I've been catching 5-10 males daily in my 'fly trap', and even a few females. Expect defoliation next year? Steve (Halifax) Quoting David & Alison Webster <dwebster@glinx.com>: > Stephen Shaw wrote: >> Hi Dave, Jean, etherealists all... >> the first thing apparent >> about why auroral sounds haven't been explained satisfactorily is >> that this is >> not a robust phenomenon at all. The accounts of the actual sound >> structure are >> variable, some hear the sounds when sometimes others in the same >> group don't, >> some individuals who hear them sometimes don't hear them most other >> times, and >> (perhaps related) this seems to depend on the local structure of the >> environment, etc. Some outside observers doubt it is a real >> phenomenon at all, >> and all seem to agree that the effects are not loud. > > Hi Steve & All, Nov 17, 2006 > I finally got around to visiting two of the sites, the more > informative being > http://members.tripod.com/~auroralsounds/ > Your condensation of general experience (above) is what I would > have expected, based on personal experience. Hearing is not a > constant, so assuming hearing is involved, anyone with less than > excellent hearing in the rustle range would not hear it. I used to > have very good hearing but at our latitude (45o) heard only faint > rustles when displays were exceptional and of course nothing when > displays were not exceptional. Over the course of several nights at > about 55o the sounds were obvious but even these obvious sounds would > easily have been swamped by a light breeze (causes ears to roar) or > background noise of any kind and perhaps even by recent exposure to > loud sounds (ears adjust relatively slowly). > > So probably the minimum conditions to experience these sounds > includes a conjunction of good hearing, calm air, dead silence, no > recent exposure to loud sound and high latitude or exceptional > displays. > > The quotation from Robert Service is a bit garbled, sulphus should > be sulphur and life should be like. He apparently was hard of hearing. > > The idea of electromagnetic waves in the audible range sounds > promising, in that they apparently have been routinely detected by > instruments, but the frequency of 4 kHz to 8 kHz does not register > directly with a rustle. So one would have to postulate out of phase > waves that produce a beat in the audible range. > > I have not done this for many decades so don't recall details, but > audible beats at frequency x can readily be produced in a > radio by injecting a second signal that differs from anRF generating > circuit by x. > Yours truly, Dave Webster, Kentville >
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