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Re: (meteorobs) Fireballs ,meteor sounds, nomenclature etc,

Aug. 15, 2002

Greetings Mr. Ed Majden and Fellow Meteor Enthusiasts!

If you were to look in the listings of the 
Meteoritical Bulletin, you will notice the many 
strange sounds that have been reported to accompany
meteorite falls.  I believe some of those either refer
to the "simultaneous sound" phenomenon that is being
discussed or were heard during certain meteorite falls
even though they were not mentioned in the print.  

As for meteors with a cometary origin being quite
different from asteroidal ones; let us not forget that
the "comet snowball" theory does not quite satisfy the
questions raised with the close-up pictures of the
latest comet fly-by.  From what I gathered, it is a 
lot more barren and/or dry on one than anyone 
expected.  I have long suspected this.   


Long Perseid trains!

Mark Fox
Newaygo, MI USA


--- Ed Majden <epmajden@shawdot ca> wrote:
>     We need some way to differentiate between
> cometary (shower) fireball
> meteors and asteroidal fireballs.  These are quite
> different phenomenon.
> Shower meteors are considered to generally be loose
> conglomerates of small
> particles some what akin to cigarette ash.  They
> make their appearance high
> in the atmosphere, generally in the region of 120 km
> to 60 km.  High
> velocity Perseid and Leonid meteors become visible
> at higher altitudes than
> their slower counterparts.  Simultaneous sound has
> been reported from one
> Leonid member.
>     On the other hand, asteroidal meteors are
> generally solid objects often
> travelling at lower velocities and they penetrate
> much lower into the
> atmosphere.  These are the type of object that may
> produce a meteorite on
> the ground.  Are they associated with simultaneous
> sound phenomenon also?
> It is difficult for a visual observer to estimate
> the velocity of a meteor
> with any certainty.  A near head on, high velocity
> Leonid may appear slow to
> an observer if it is nearly head-on where it appears
> fast further from the
> radiant.
>     Generally we term a meteor a fireball if it is
> brighter than -3.0
> magnitude or so.  Depending on the type of fireball
> your taking about,
> shower type or meteorite dropping kind, this should
> be re-defined.  A -3.0
> fireball is not likely to drop a meteorite.
>     These definitions should be refined by the
> professional nomenclature
> groups so when people talk about these things we are
> talking about the same
> thing!
> 
> Ed Majden
> 
> 
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