[meteorite-list] Meteorites 101-Bolide

From: Mark Bowling <minador_at_meteoritecentral.com>
Date: Mon, 17 Jan 2011 08:08:20 -0800 (PST)
Message-ID: <647671.89126.qm_at_web161406.mail.bf1.yahoo.com>

Hi Jeff & all,
Though I'm not entirely clear on the details, I think I heard the term through
discussion in the past (just not fresh in my memory the details of those
discussion/lectures), but also through reading some old references.??A few years
ago, I spent some time rechecking my books when I started to hear "bolide" used
more "loosely" (or better, I heard it used differently than what I understood it
to mean).? I was beginning to wonder if I had misunderstood and had been using
the term incorrectly.? I came to the conclusion that?I was not mistaken,?so
continued to use it as before.

I have read similar definitions as given by your reference, but I just haven't
interpreted (rightly or wrongly) the last part (explodes) as indicating an
audible report.? But more of a visual indication - sometimes they are quite
dramatic, even though you still don't hear them?(you can imagine the violence of
the occurrence).? If you do hear them, that means it's fairly close by (and
great to know and experience!).? That's just the way I've interpreted very
similar definitions - but that's just me.? :)

Looking forward to a more official definition (and hoping they change their mind
about Pluto too ;-P).

Clear skies,
Mark

P.S. Thanks Martin for the interesting history!



----- Original Message ----
From: Jeff Kuyken <info at meteorites.com.au>
To: MEM <mstreman53 at yahoo.com>; metlist <meteorite-list at meteoritecentral.com>
Sent: Mon, January 17, 2011 4:26:05 AM
Subject: Re: [meteorite-list] Meteorites 101-Bolide

Hi Elton & all,

It's funny but I've always been under the same impression as Elton in regards to
the term bolide. I'm not sure why though! Basically I've always believed the
following to be an approximate summary:

"Meteor" - basically a generic term for all meteors and associated light
phenomena.
"Fireball" - exceptionally large and bright meteor at least as bright as Venus
(i.e. -3 to -4 mag). Disintegrating body / sparks etc is still possible with a
fireball.
"Bolide" - basically a "Fireball" PLUS an audible report.

I believe the term bolide originally stems from the Latin term "bolis" which
roughly translates to a very large fiery meteor with some sources also
referencing the associated audible phenomena. The earliest published reference I
found online for "bolis" was Webster's Revised Unabridged Dictionary (1913)
"(n.) A meteor or brilliant shooting star, followed by a train of light or
sparks; esp. one which explodes."

I guess there are many variations and opinions. For the most part... they're
probably all pretty much correct.

Cheers,

Jeff


----- Original Message ----- From: "MEM" <mstreman53 at yahoo.com>
To: "Mark Bowling" <minador at yahoo.com>; "metlist"
<meteorite-list at meteoritecentral.com>
Sent: Monday, January 17, 2011 8:56 AM
Subject: Re: [meteorite-list] Meteorites 101-Bolide


> We differ some Mark, in that a bolide is not just a fireball showing
> framentation-- such as we saw in the Peekskill fireball.? IMO, historically
and
> by traditional use: a bolide is not just a simple fragmentation but an
>explosive
> rupture which occurs at the practical end of incandescent flight--Like an
>upside
> down bottle rocket.? Perhaps, it is somewhat subjective, and while it may
occur
> out of ear shod, the explosive expansion part has a distinct sound/report
> different from a sonic boom.? The term was adapted possibly from a discussion
>of
> military rocketry into early descriptions of meteor fireballs which exploded.
>
> Perhaps it is just me but I subscribe to these characteristics of a bolide
> because it describes a specific combination of conditions. The audible report
> component is most always associated with the early literature accounts
> describing a fireball as a bolide.? In my bolide theory I believe there is an
> envelope of stress/shear as the meteoroid is undergoing, being dramatically
> slowed by the atmosphere. If the envelope is not violated the meator may
> fragment but it does not do so explosively.? Around 5 miles above sea level
the
> meteoroid encounters the boundary of that momentum /shear envelope which
> reflects maximum aerodynamic pressure at which the meteoroid can retain
> integrity.? This transition is so abrupt for the meteoroid, that it literally
> shears along molecular bonds releasing a fair amount of heat and possibly
rapid
> oxidation of iron particles, etc.
>
>
> Elton
>
>
>
> ----- Original Message ----
>> From: Mark Bowling <minador at yahoo.com>
>> To: meteorite-list at meteoritecentral.com
>> Sent: Sun, January 16, 2011 12:11:03 PM
>> Subject: Re: [meteorite-list] Meteorites 101-Bolide
>>
>> Hi all,
>> I have understood from my study that a bolide refers to a meteor that breaks
>> up
>>
>> - not requiring the detection of an audible report because, if? observed from
>a
>>
>> distance, the sound may not be heard.? It is not a bright? meteor or fireball
>> or
>>
>> large impactor, but simply a meteor that breaks up.? Right or wrong, that's
>> the
>>
>> way I've been using the term when I report seeing? one on the list.? Has
>> anybody
>>
>> else been using it that way?? I've been lucky? to have seen several dozen
over
>
>> the years (often colorful), but none up? close like Elton (yet!).
>>
>> I would agree that the IAU should come up with a? definition because the
>> term has
>>
>> come to mean too many things and its use? is not going to go away any time
>> soon.
>>
>> In fact with the current explosion? of public interest (no pun intended),
more
>
>> people are going to find the term? and grab onto it.
>>
>> See you all soon!
>> Mark B.
>> Vail,? AZ
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Received on Mon 17 Jan 2011 11:08:20 AM PST