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Re: (meteorobs) Fireballs & sonic booms

Lew Gramer wrote:
> 
> So I guess my question then is the same as that of another respondent:
> what independent evidence is there of simultaneous sounds being heard
> for less-bright fireballs - say in the -6 to -10 magnitude range? I'd
> be interested to hear on-list from any *OTHER* observers with data to
> share (negative or otherwise) of this effect in lesser fireballs...
> 

  I may have a picture of such fireball.  The fireball looks quite small
and insignificant.  It's 4 degrees long and the latter half is bright - a 
bit broader track then Vega when you expose it 10 minutes on ISO400 film using 
24 mm objective at f2.8 (as I did).  Maybe that gives some ideas of its
brightness.

  I never saw the fireball since I was facing east and my camera west.  As
it happened I was lying on the roof and heard a sound behind.  I turned swiftly
and looked directly at the right place in the sky where it had happend and
only then I realize that I knew (or should I say: knew roughly) the right place 
in the sky because of the sound.  Realizing that I had reacted automatically 
without thinking of my moves and reactions, was a wild sensation by itself.  I'm 
and I was absolutely sure that it was the sense of hearing the sound in 3D that 
help me to locate the right spot instantly, not the illumination around me.

  The sound wasn't hissing, whoosing or cracking as others have heard.  And
although it was short, soft and gentle, yet it was quite clear.  To describe it 
best the sound was something like sound effects in old movies 50 years ago when 
photographs were taken using magnesium flash cubes (or what ever they are called),
or like a sound of air rushing in when something thight (plug) comes out of a 
hollow pipe after traveling it through.  The sound came probably from an explosion
as there is small gap and spot after the main fireball track faded.

  Time was August 8.-9. in 1993, waiting for a big Perseids showdown, but the
actual peak time was clouded as usual.  Since I didn't see the fireball but
heard the sound, this should exclude meteor sounds as psychological effects.
Maybe the reason why these sounds are not heard more often is that they are so
faint.  There shouldn't be traffic, wind or any other distracting sounds in nature.
And these conditions are hard to meet as there is always a car rumbling in a
distant highway or dog barking or some rustle that you create youself.

Markku

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