[meteorite-list] Small Asteroid 2010 AL30 Will Fly Past TheEarth

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Wed, 13 Jan 2010 01:14:29 -0600
Message-ID: <3DF617D65C27491AA82552DA139251B2_at_ATARIENGINE2>

Just to make things even more confusing,
the IAU itself has approved the use of the
term "meteor" in a dual sense to include the
physical body itself, thus equating "meteoroid"
with "meteor."

Say what?

Bob Verrish wrote an article about it:
http://meteorite-recovery.tripod.com/2008/mar08.htm

I quote the IAU:

Definition of terms by the IAU Commission 22, 1961.

A. meteor: in particular, the light phenomenon which results
from the entry into the Earth's atmosphere of a solid particle
from space; more generally, as a noun or an adjective, ANY
PHYSICAL OBJECT or phenomenon associated with such
an event.

B. meteoroid: a solid object moving in interplanetary space,
of a size considerably smaller than an asteroid and considerably
larger than an atom or molecule.

C. meteorite: any object defined under B which has reached
the surface of the Earth without being completely vaporized.

D. meteoric: the adjectival form pertaining to definitions A and B.

E. meteoritic: the adjectival form pertaining to definition C.

F. fireball: a bright meteor with luminosity which equals or
exceeds that of the brightest planets.

G. micrometeorite: a very small meteorite or meteoritic particle
with a diameter in general less than a millimeter.

Now, is everything perfectly clear?

I didn't think so...


Sterling K. Webb
---------------------------------------------------------------------------------------------
----- Original Message -----
From: "Jason Utas" <meteoritekid at gmail.com>
To: "Meteorite-list" <meteorite-list at meteoritecentral.com>
Sent: Wednesday, January 13, 2010 12:49 AM
Subject: Re: [meteorite-list] Small Asteroid 2010 AL30 Will Fly Past
TheEarth


Hello Sterling, Larry, All,
Interesting - there's another problem with Sterling's initial
definition, of which the following statement was a component:

"2010 AL30 could be a "meteoroid" if it would hit and
leave a piece to be recovered. Just be very patient and
live a long time... (Always a good idea anyway.)"

As per that definition, though, there's a problem when it comes to
single crater-forming meteorites that don't leave pieces to be
recovered. Yes, they hit the earth, but if they can't be recovered in
any way, can they really be called meteorites (because they don't
technically produce recoverable 'meteorites')?

Admittedly that argument is only a problem if we're using the outdated
version of the definition, but it raises another question.

If an interplanetary object does strike the surface of the earth - and
vaporizes upon impact, is it still considered a meteorite?
Are craters formed by meteorites? Asteroids? I assume a meteoroid
wouldn't be large enough to vaporize itself on impact, but even the
faintest of shooting stars produce dust particles which will
eventually reach the ground.
- So there's a minimum size limit on "meteorites" - they must be
larger than the dust produced by fireballs themselves (apparently),
but as for crater-forming bodies...I've always simply called them
meteorites because, well, in my mind, they've struck the surface of
the earth, so they're meteorites.
Trouble arises if the language of the currently used definition is
specific enough to note that for a meteorite to be a meteorite,
fragments must be recoverable. And if that's the case, then many
craters were in fact formed by...Asteroids? This definition would
also change on individual crater's with time, as older craters might
have arrived with recoverable fragments, but such pieces could have
since been lost to time and weathering (craters generally outlast
meteorite fragments, after all).

So...yeah. A few problems.
Any thoughts?

Regards,
Jason

On Tue, Jan 12, 2010 at 10:04 PM, <geozay at aol.com> wrote:
>
>
>
>>>"My" definition of "meteoroid" is just the standard
> textbook definition. Before it hits the Earth, it's
> a "meteoroid." While in fiery flight through the
> atmosphere, it's a "meteor." If a piece lands on the
> Earth (and somebody finds it), it's a "meteorite."<<
>
> I understood that a meteoroid is a small bodied natural object, in a
> separate solar orbit from that of earth's. When it enters the earths
> atmosphere
> and in the incandescent phase, the visible phenomena is a meteor.
> Afterwards, during the dark phase, its no longer in a separate solar
> orbit from that
> of the earth's. It has yet to hit the ground to become a meteorite.
> What
> is this object called during the dark phase? I personally call it a
> meteorite since its under the control of the earth at that point and
> not
> independent of the earth. Also there has been detected by various
> space probes out
> around Jupiter, "meteoroids" that are too fast to be in solar orbit
> and thus
> of interstellar origins. Are these still called meteoroids?
> GeoZay
>
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Received on Wed 13 Jan 2010 02:14:29 AM PST