[meteorite-list] "Meteorite and meteoroid: New comprehensive definitions"

[drtanuki]

Larry, Shawn and List,
  I have re-posted the abstract of Meteorite and meteoroid: New comprehensive definitions by Alan E. RUBIN and Jeffrey N. GROSSMAN at:

http://lunarmeteoritehunters.blogspot.com/2010/04/meteorite-and-meteoroid-new.html

Best Regards, Dirk Ross...Tokyo

--- On Sun, 4/4/10, lebofsky at lpl.arizona.edu <lebofsky at lpl.arizona.edu> wrote:

> From: lebofsky at lpl.arizona.edu <lebofsky at lpl.arizona.edu>
> Subject: Re: [meteorite-list] "Meteorite and meteoroid: New comprehensive definitions"
> To: "Shawn Alan" <photophlow at yahoo.com>
> Cc: meteorite-list at meteoritecentral.com
> Date: Sunday, April 4, 2010, 11:37 AM
> Hi Alan:
> 
> Thanks for this. Where was this published? Some of the
> numbers did not
> come though. This works fine with me other than,if read
> this correctly, it
> does not classify anything larger than a meter. What are
> those objects?
> 
> There was a discussion of this topic some time ago and one
> needs to take
> into account some that has been observed and has its orbit
> determined.
> Technically this is an asteroid since the IAU does not
> number/name
> meteoroids. This can be down to about 5 meters (not sure
> what the smallest
> NEO observed is). I would be hard pressed to call
> everything larger than 1
> meter (if I read this right) an asteroid.
> 
> My two cents.
> 
> Larry
> 
> > Hello Listers,
> >
> > Here is an intersting artical I found that explains
> new comprehensive
> > definitions about meteorites. Down below is an
> abstract from the artical
> > and a short introduction into the what is disussed
> about new definitions.
> >
> >
> > Meteorite and meteoroid: New comprehensive
> definitions
> >
> > Alan E. RUBIN1* and Jeffrey N. GROSSMAN2
> > 1Institute of Geophysics and Planetary Physics,
> University of California,
> > Los Angeles, California 90095–1567, USA
> > 2U.S. Geological Survey, 954 National Center, Reston,
> Virginia 20192, USA
> > *Corresponding author. E-mail: aerubin at ucla.edu
> > (Received 05 May 2009; revision accepted 14 September
> 2009)
> > Â 
> > Abstract–Meteorites have traditionally been
> defined as solid objects
> > that have fallen to Earthfrom space. This definition,
> however, is no
> > longer adequate. In recent decades, man-made objects
> have fallen to Earth
> > from space, meteorites have been identified on the
> Moon andMars, and small
> > interplanetary objects have impacted orbiting
> spacecraft. Taking these
> > factsand other potential complications into
> consideration, we offer new
> > comprehensive definitions of the terms
> ‘‘meteorite,’’
> > ‘‘meteoroid,’’ and their
> smaller counterparts: A meteoroid is a
> > 10-lm to 1-m-size natural solid object moving in
> interplanetary space.
> > Amicrometeoroid is a meteoroid 10 lm to 2 mm in size.
> A meteorite is a
> > natural, solid object
> > larger than 10 lm in size, derived from a celestial
> body, that was
> > transported by naturalmeans from the body on which it
> formed to a region
> > outside the dominant gravitational influence of that
> body and that later
> > collided with a natural or artificial body larger
> than
> > itself (even if it is the same body from which it was
> launched).
> > Weathering and other secondary processes do not affect
> an object’s
> > status as a meteorite as long as something
> recognizable remains of its
> > original minerals or structure. An object loses its
> status as a
> > meteorite if it is incorporated into a larger rock
> that becomes a
> > meteorite itself. A micrometeorite is a meteorite
> between 10 lm and 2 mm
> > in size.
> > Â 
> > Meteorite–‘‘a solid substance or
> body falling from the high regions
> > of the atmosphere’’(Craig 1849);
> ‘‘[a] mass of stone and iron that
> > ha[s] been directly observed to have fallen down to
> the Earth’s
> > surface’’ (translated from Cohen 1894);
> ‘‘[a] solid bod[y] which
> > came to the earth from space’’
> (Farrington 1915); ‘‘A mass of
> > solid matter, too small to be
> > considered an asteroid; either traveling through space
> as an unattached
> > unit, or having landed on the earth and still
> retaining its identity’’
> > (Nininger 1933); ‘‘[a meteoroid] which has
> reached the surface of the
> > Earth without being vaporized’’ (1958
> International
> > Astronomical Union (IAU) definition, quoted by Millman
> 1961); ‘‘a
> > solid body which has arrived on the Earth from outer
> space’’ (Mason
> > 1962); ‘‘[a] solid bod[y] which reach[es]
> the Earth (or the Moon,
> > Mars, etc.) from interplanetary space and [is] large
> enough to survive
> > passage through the Earth’s (or Mars’,
> etc.) atmosphere’’ (Gomes
> > and Keil 1980); ‘‘[a meteoroid] that
> survive[s] passage through the
> > atmosphere and fall[s] to earth’’
> (Burke1986); ‘‘a recovered
> > fragment of a meteoroid that has survived transit
> through the
> > earth’satmosphere’’ (McSween
> 1987); ‘‘[a] solid bod[y] of
> > extraterrestrial material that penetrate[s]
> > the atmosphere and reach[es] the Earth’s
> surface’’ (Krot et al.
> > 2003).
> > Â 
> > INTRODUCTION
> > Since Chladni (1794) published On the Origin of the
> > Pallas Iron and Others Similar to it, and on Some
> > Associated Natural Phenomena and made plausible the
> > hypothesis that rocks could fall from the sky, the
> > definition of the word meteorite has remained
> essentially
> > unchanged, as reflected in the ten quotations given
> > above. Nearly all modern reference works use a
> similar
> > definition. Meteorites are almost always defined to
> be
> > solid bodies that have fallen through the
> Earth’s
> > atmosphere and landed on the Earth’s surface.
> > Â 
> > Many recent definitions of meteorite, including the
> > one adopted by the International Astronomical Union
> > (IAU), specify that meteorites originated as
> meteoroids.
> > The latter term was defined by the IAU as
> ‘‘a solid
> > object moving in interplanetary space, of a size
> > considerably smaller than an asteroid and
> considerably
> > larger than an atom or molecule’’
> (Millman 1961). Beech
> > and Steel (1995) suggested modifying this definition
> to
> > include only natural objects in the size range 100 lm
> to
> > 10 m. Because modern usage frequently ties these two
> > terms together, with meteoroids forming the
> pre-impact
> > precursors of meteorites, it is imperative that the
> > definitions be consistent.
> > Â 
> > With the advent of the Space Age and the discovery
> > of new sources of extraterrestrial material, it is
> clear
> > that most existing definitions of the term meteorite
> are
> > too restrictive. Indeed, there are already three
> objects
> > recognized by the Meteoritical Society’s
> Committee on
> > Meteorite Nomenclature (NomCom) that violate most
> > traditional definitions of meteorite (with the
> exception
> > of the one given in Gomes and Keil 1980) because they
> > were not found on Earth’s surface. Two
> millimeter-size
> > chondrites discovered among samples returned from the
> > Moon during the Apollo missions have been described
> > and named as meteorites: Bench Crater (McSween 1976;
> > Zolensky et al. 1996) and Hadley Rille (Haggerty
> 1972;
> > Grossman 1997; Rubin 1997). A IAB-complex iron
> > identified on the surface of Mars by the Opportunity
> > rover was recently given a formal meteorite name:
> > Meridiani Planum (Connolly et al. 2006; Schro¨ der
> et al.
> > 2008). The existence of these objects, combined with
> > other probable meteorites from the Moon and Mars
> > that have not yet been formally named (as well as
> other
> > conceivable examples), has led us to re-examine the
> > term meteorite and the related term meteoroid in a
> > search for precise, comprehensive definitions.
> > Â 
> > Shawn Alan
> > ______________________________________________
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