Hi Bruce and Tom R,
Thanks for that follow-up info on your own meteor recording endeavors.
Very interesting.
Regarding whether this subject is off-topic or not :-) : I know this
list is bird oriented but I would consider comet/meteor phenomena as
nature phenomena. There is the possibility that comets have seeded life
throughout the cosmos and that there could be microbes and/or microbial
precursors within cometary dust that enters Earth. Each comet is unique
and has a long individual history in space. It is possible that some
comets have heat from radioactive processes and may be shell containers
with warm nutrient oceans sloshing around inside. A wet and warm comet
coming from the far reaches of outer space could actually be a complex
and sovereign microbe nation.
Who knows? Maybe there is a bio-signature within the scatter recordings.
The mechanisms of nature recording are an evolving technology.
Thomas Ashcraft
tk7859 wrote:
> --- In "Bruce Wilson"
> <> wrote:
>
>> Just to make it clear for those who don't know radio scattering methods,
>> these are recordings not of the sound the meteors make when entering the
>> atmosphere (they don't seem to make much sound at all, radio or
>>
> aural), but
>
>> the sounds of over-the-horizon FM radio stations that reflect off the
>> ionized trail in the wake of a meteors passage and become audible
>>
> for a very
>
>
>> short time, the duration of the ionized trail.
>>
>> They aren't strictly nature recordings, but they are very interesting.
>>
>
>
> To take this Off Topic subject just a little further:
>
> In 2001/2002 I helped the ESA (European Space Agency) do some tests
> during the Leonids showers.
>
> The technique was different to that described by Bruce above and
> involved recording the doppler shift, caused my a meteor's ionisation
> trail, of an unmodulated BBC short wave radio transmission. My
> involvement was due to my location relative to the transmitter being
> suitable for recording the doppler shift using the R-meteor
> spectrogram program
>
> http://sapp.telepac.pt/coaa/r_meteor.htm
>
> Some spectacular dopplergrams were obtained. The following links give
> more detail of the experiment
>
> http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=3D29005
> http://www.meteorobs.org/maillist/msg24252.html
>
> By converting the hf doppler changes to audio frequencies it was
> possible to "hear" the visual traces. This web page gives a link to a
> .wav file of the sound of the trace
>
> http://www.esa.int/esaSC/SEMSS0XLDMD_sensations_0.html
>
> I understand the plan was to collect dopplergrams of the sane meteors
> as they appeared at different points on the globe. From this info it
> would be possible to develop a three dimensional dopplergram and
> thereby gain more understanding.
>
> I forwarded my dopplergrams to the ESA but never heard anything again.
>
> As I said, at the beginning of this post, this is off topic but it
> does have a whiff of sonogram analysis about it ;-)
>
> Cheers
>
> Tom Robinson
>
>
>
>
>
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