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(meteorobs) Re: [nhas] Did you hear any Leonids?




NOTE: George D. is not a current 'meteorobs' reader! If you follow up,
please MANUALLY put 'drobnock@penn.com' in the "Cc:" line of your reply!
Lew Gramer <owner-meteorobs@atmob.org>


The question of meteors producing electrophonic sound is controversal.

There are several thoughts on a meteor producing "sound" or very low 
frequency electromagnetic signitures or radio waves.

1. A meteor entering the atmosphere creates a sonic wave, producing 
sound, as thunder or "bang".

2. A meteor enters the atmosphere and a sound is produced by very low 
frequency electromagnetic waves. The VLF electromagnetic energy being 
recetified by an object near the observer, on an object on the 
observer. The objsct rectifies the eletromagnetic energy into sound. 
Producing a "hiss" or "sizzle." This is only thought possible for 
meteors of magnitude of > -6. 

3. An meteor of significant mass to produce a meteor of magnitude of, 
for discussion, +/- 2, will produce VLF signatures that can be 
received with a very low frequency receiver. The signal or noise is 
the same as a sfenic or atmospheric. This may take the form of a 
"tweak" or "whistle".

4. As a cloud of dust begins to enter the atmosphere, forming micro 
meteors prior to a meteor storm, small amounts of VLF energy is 
released producing an increase in background noise.

5. As a meteor enters the atmosphere only under certain conditions,
as yet unknow, meteors produce a vlf signature or electrophonics.

6. An there may be any other explaniations !

On a personal note: Located in central Pennsylvania, during the 
morning of the 18th of November, we a team of 5 and two visitors. We 
were able to observe with a vlf receiver, using an analogue meter (as 
on of the outputs), and record on an audio tape, an increase in 
background sferics (atmospheric noise) and what appeared as a 
correlation between a "tweak" and the sighting of a meteor. During
the observation period, the tape has a signature or noise that
corresponds with other east coast sightings of a -6 fireball. 
Listening to the tape, we hear a "hiss." But no one heard a sound 
during observation. 

The impression, from the audio and observation of the meter readings 
was similar to observing a the beginning of a summer storm to form 
before the first strike of lighting.

George John Drobnock <drobnock@penn.com>

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