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(meteorobs) Re: Chirping firebaLL



Make,
There is a well reported --but not yet understood, phenomena called "electrophonic sound" associated with some meteors. Theories are that the very low frequency radio waves created
by the plasma cause some objects on the ground to vibrate. When they vibrate they produce sonic noise. Observers hear the sound simultaneously with the fireball.  They may or may
not hear the subsequent sonic boom as well.   So don't worry that you are hallucinating and be happy that you have heard something that might happen only once in your life time.

Regards,
Elton

>
> Date: Mon, 12 Aug 2002 22:31:20 +0300
> From: Markku Vanamo <mvanamo@pp.inet.fi>
> Subject: (meteorobs) Chirping fireball
>
> Last night (11/12 August) I was observing Perseids here in southern
> Finland and I saw a bright fireball, which wasn't a perseid, though.
> At about 21:47 UT, at a height of 25-30 degrees, about 15 degrees below
> the Big Dipper, flared rather slow fireball.  My wild guess is that it
> was about -8 magnitude, but that really is a rough estimate since it
> happened behind trees and bright fireballs run out of my scale anyway.
> I first though the light was coming from the nearby road.  But with no
> noise of an engine, my bet then was a bird as it made alike sound.  When
> I got so far that there're no birds that shine and I should turn my head
> and make sure of that, few seconds had already passed.
>
> The sound was simultaneous with the fireball, clearly audible and coming
> from that direction.  It sounded like a bird, kind of kwiek-kwiek-kwiek
> noise.  Or like a sound that holes in a fast flying, rotating (bowling)
> ball would make when travelling through air.  These, maybe 6-8, kwiek-sounds
> had a sliding down pitch, lasting about half a second each and it seemed
> to occur at the same time as the fireball was getting brighter, flaring.
> But I can't be sure of this because I saw it through the trees.  The
> tree trunks might have caused that, but the sound beat was so regular
> and the trunks are so unevenly lined up that, the sound itself couldn't
> have been constant and broken down by the trees.
>
> My observing place was the same as the last time, and the first time
> (in 1992), I heard a noisy fireball - on the roof, in a lawn chair.
> This fireball last night, I saw it about half the length of the Big
> Dipper, but it probably travelled at least twice that long and from
> the handle to the bowl direction.  It took me by surprise, so all
> the above are very, very crude estimates of it.  I wonder if anybody
> else in Scandinavia saw it with or without the sound.
>
> Make
> 61N25W
>
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