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

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Thu, 25 Apr 2013 22:04:45 +0100
Message-ID: <il0hho9r6w0dngqlpkjmcd7t.1366923885798_at_email.android.com>

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 Thu 25 Apr 2013 05:04:45 PM PDT