[meteorite-list] Meteorites 101-Bolide

From: MEM <mstreman53_at_meteoritecentral.com>
Date: Sun, 16 Jan 2011 13:56:15 -0800 (PST)
Message-ID: <210385.30145.qm_at_web161909.mail.bf1.yahoo.com>

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
Received on Sun 16 Jan 2011 04:56:15 PM PST