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Re: (meteorobs) hearing meteors impacting the atmosphere


Hi,

Low fequency sound waves seem to be recorded quite well by certain recorder
microphones (even without additions) according to the Dutch meteorological
Institute, who is experimenting with such low frequency setups in order to
investigate the several 'sonic booms' of unknown origin that are heard last
years. So that underlines your experiments and preliminary conclusions I
guess. It is interrseting: if some meteor sonic booms can indeed be
recorded thsi way....

Sound from meteors can also be heard instantanious sometimes
('electrophonic noise'), with bright fireballs, The theory is that VLF
radiowaves (1-10KHz) are produced by such bolides, which can transform into
audible sounds due to certain materials, e.g. paper etc. Dr Keay has
written some interresting papers on that. It has been highly controversial
for a long time, but it is now increasingly becoming clear that such things
indeed happen.
I have heard 'electrophic noise' myself once (in 1990).

-Marco






At 01:54 1998-08-16 +0000, you wrote:
>There may be something to hearing meteors impacting the atmosphere
>using a corregated tube. I was at a hardware store the other day, and
>saw some 3/4 inch corregated plastic elctric conduit for about $.30 a
>foot, so I bought 40 feet of it. I hung it near vertical from my TV
>antenna. I had to cut 4 feet off. I did not have a microphone, so I put
>a speaker facing up at the end of the tube. I ran wire the fifty feet
>inside, and hooked it to the phono jack of my stereo. I have to turn the
>stereo up almost all the way. I was out looking up, and I saw a nice
>yellow meteor go right over the house. I went inside and saw it was
>1:07. At 1:11 a boom came from my speakers. There was a secondery boom
>many seconds later.
>     The theory is that the corregations cause eddies in the tube which
>convert the below 20 Htz sound waves into higher frequencies that can be
>heard. The low frequency sound waves travel a lot farther than higher
>frequencies.
>     I will post again when I have more credible evidence.
>     Airplanes and jets cause sort of a rumble.
>
>
References: