[meteorite-list] Cassini Observes Meteors Colliding With Saturn's Rings

From: Robert Verish <bolidechaser_at_meteoritecentral.com>
Date: Fri, 26 Apr 2013 19:19:05 -0700 (PDT)
Message-ID: <1367029145.22217.YahooMailClassic_at_web142501.mail.bf1.yahoo.com>

Actually, Chris,
the IAU has already formalized that definition of "meteor".
It did so back in 1961.
I've explained what I mean by all of this in my article:

http://meteorite-recovery.tripod.com/2008/mar08.htm

Apparently, a well-respected astronomer wrote a popular book soon after the 1961 General Assembly met and the XI Committee of the IAU formalized the definitions of meteoroid, meteor, and meteorite. The author defined those same terms in his book, stating that the definitions came from the IAU, except that he clearly changed the definition of "meteor".

Apparently, this author departed from the IAU definition of "meteoroid", including it as the object which produces the light display (meteor). Whereas, the IAU definition of meteoroid is that it orbits the Sun, and that when this same body enters the influence of the Earth (it is no longer orbiting the Sun) that object is now termed a "meteor".

So, in recap, IAU definitions: Meteoroid to Meteor to Meteorite
but the author's misdefinition: Meteoroid to Meteorite

>From that point forward to the present, the wrong definition has been perpetuated.

--Bob V.

--- On Thu, 4/25/13, Chris Peterson <clp at alumni.caltech.edu> wrote:

> From: Chris Peterson <clp at alumni.caltech.edu>
> Subject: Re: [meteorite-list] Cassini Observes Meteors Colliding With Saturn's Rings
> To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>
> Date: Thursday, April 25, 2013, 2:04 PM
>
> I'd agree that a meteor can't collide with Saturn's rings, but
> it would be correct usage to say a
> meteor collided with an airplane, a bird, or maybe even the
> ground were it still hypersonic and ablating, since at that
> stage both the visual effect and the body itself are
> typically called a "meteor" (something the IAU is
> considering formalizing last I heard).
>
> Chris
>
> ****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
> Michael Mulgrew <mikestang at gmail.com> wrote:
>
> >A "meteor" can't collide with anything!
> >
> >Michael in so. Cal.
> >
> >On Thu, Apr 25, 2013 at 12:34 PM, Ron Baalke <baalke at zagami.jpl.nasa.gov>
> wrote:
> >>
> >>
> >>
> >> April 25, 2013
> >>
> >> Dwayne Brown
> >> Headquarters, Washington
> >> 202-358-1726
> >> dwayne.c.brown at nasa.gov
> >>
> >> Jia-Rui C. Cook
> >> Jet Propulsion Laboratory, Pasadena, Calif.
> >> 818-354-0850
> >> jccook at jpl.nasa.gov
> >>
> >> RELEASE: 13-120
> >>
> >> NASA PROBE OBSERVES METEORS COLLIDING WITH SATURN'S
> RINGS
> >>
> >> WASHINGTON -- NASA's Cassini spacecraft has
> provided the first direct
> >> evidence of small meteoroids breaking into streams
> of rubble and
> >> crashing into Saturn's rings.
> >>
> >> These observations make Saturn's rings the only
> location besides
> >> Earth, the moon, and Jupiter where scientists and
> amateur astronomers
> >> have been able to observe impacts as they occur.
> Studying the impact
> >> rate of meteoroids from outside the Saturn system
> helps scientists
> >> understand how different planet systems in the
> solar system formed.
> >>
> >> Our solar system is full of small, speeding
> objects. Planetary bodies
> >> frequently are pummeled by them. The meteoroids at
> Saturn range from
> >> about one-half inch to several yards (1 centimeter
> to several meters)
> >> in size. It took scientists years to distinguish
> tracks left by nine
> >> meteoroids in 2005, 2009 and 2012.
> >>
> >> Details of the observations appear in a paper in
> the Thursday edition
> >> of Science.
> >>
> >> Results from Cassini already have shown Saturn's
> rings act as very
> >> effective detectors of many kinds of surrounding
> phenomena, including
> >> the interior structure of the planet and the orbits
> of its moons. For
> >> example, a subtle but extensive corrugation that
> ripples 12,000 miles
> >> (19,000 kilometers) across the innermost rings
> tells of a very large
> >> meteoroid impact in 1983.
> >>
> >> "These new results imply the current-day impact
> rates for small
> >> particles at Saturn are about the same as those at
> Earth-- two very
> >> different neighborhoods in our solar system, and
> this is exciting to
> >> see," said Linda Spilker, Cassini project scientist
> at NASA's Jet
> >> Propulsion Laboratory (JPL) in Pasadena, Calif. "It
> took Saturn's
> >> rings acting like a giant meteoroid detector -- 100
> times the surface
> >> area of the Earth -- and Cassini's long-term tour
> of the Saturn
> >> system to address this question."
> >>
> >> The Saturnian equinox in summer 2009 was an
> especially good time to
> >> see the debris left by meteoroid impacts. The very
> shallow sun angle
> >> on the rings caused the clouds of debris to look
> bright against the
> >> darkened rings in pictures from Cassini's imaging
> science subsystem.
> >>
> >> "We knew these little impacts were constantly
> occurring, but we didn't
> >> know how big or how frequent they might be, and we
> didn't necessarily
> >> expect them to take the form of spectacular
> shearing clouds," said
> >> Matt Tiscareno, lead author of the paper and a
> Cassini participating
> >> scientist at Cornell University in Ithaca, N.Y.
> "The sunlight shining
> >> edge-on to the rings at the Saturnian equinox acted
> like an
> >> anti-cloaking device, so these usually invisible
> features became
> >> plain to see."
> >>
> >> Tiscareno and his colleagues now think meteoroids
> of this size
> >> probably break up on a first encounter with the
> rings, creating
> >> smaller, slower pieces that then enter into orbit
> around Saturn. The
> >> impact into the rings of these secondary meteoroid
> bits kicks up the
> >> clouds. The tiny particles forming these clouds
> have a range of
> >> orbital speeds around Saturn. The clouds they form
> soon are pulled
> >> into diagonal, extended bright streaks.
> >>
> >> "Saturn's rings are unusually bright and clean,
> leading some to
> >> suggest that the rings are actually much younger
> than Saturn," said
> >> Jeff Cuzzi, a co-author of the paper and a Cassini
> interdisciplinary
> >> scientist specializing in planetary rings and dust
> at NASA's Ames
> >> Research Center in Moffett Field, Calif. "To assess
> this dramatic
> >> claim, we must know more about the rate at which
> outside material is
> >> bombarding the rings. This latest analysis helps
> fill in that story
> >> with detection of impactors of a size that we
> weren't previously able
> >> to detect directly."
> >>
> >> The Cassini-Huygens mission is a cooperative
> project of NASA, the
> >> European Space Agency and the Italian Space Agency.
> JPL manages the
> >> Cassini-Huygens mission for NASA's Science Mission
> Directorate in
> >> Washington. JPL designed, developed and assembled
> the Cassini orbiter
> >> and its two onboard cameras. The imaging team
> consists of scientists
> >> from the United States, England, France and
> Germany. The imaging
> >> operations center is based at the Space Science
> Institute in Boulder,
> >> Colo.
> >>
> >> For images of the impacts and information about
> Cassini, visit:
> >>
> >> http://www.nasa.gov/cassini
> >>
> >> -end-
> >>
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Received on Fri 26 Apr 2013 10:19:05 PM PDT