[meteorite-list] Scientists Discover New Ring and Other Features at Saturn

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Sep 19 19:38:01 2006
Message-ID: <200609192337.QAA22415_at_zagami.jpl.nasa.gov>

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Carolina Martinez 818-354-9382
Jet Propulsion Laboratory, Pasadena, Calif.

Preston Dyches 720-974-5859
Cassini Imaging Central Laboratory for Operations
Space Science Institute, Boulder, Colo.
                                                 
News Release: 2006-110 September 19, 2006

Scientists Discover New Ring and Other Features at Saturn

Saturn sports a new ring in an image taken by NASA's Cassini
spacecraft on Sunday, Sept. 17, during a one-of-a-kind
observation.

Other spectacular sights captured by Cassini's cameras
include wispy fingers of icy material stretching out tens of
thousands of kilometers from the active moon, Enceladus,
and a cameo color appearance by planet Earth.

The images were obtained during the longest solar occultation
of Cassini's four-year mission. During a solar occultation,
the sun passes directly behind Saturn, and Cassini lies in
the shadow of Saturn while the rings are brilliantly backlit.
Usually, an occultation lasts only about an hour, but this
time it was a 12-hour marathon.

Sunday's occultation allowed Cassini to map the presence of
microscopic particles that are not normally visible across
the ring system. As a result, Cassini saw the entire inner
Saturnian system in a new light.

The new ring is a tenuous feature, visible outside the
brighter main rings of Saturn and inside the G and E rings,
and coincides with the orbits of Saturn's moons Janus and
Epimetheus. Scientists expected that meteoroid impacts on
Janus and Epimetheus might kick particles off the moons'
surfaces and inject them into Saturn orbit, but they were
surprised that a well-defined ring structure exists at this
location.

Saturn's extensive, diffuse E ring, the outermost ring, had
previously been imaged one small section at a time. The
12-hour marathon enabled scientists to see the entire
structure in one view. The moon Enceladus is seen sweeping
through the E ring, extending wispy, fingerlike projections
into the ring. These very likely consist of tiny ice
particles being ejected from Enceladus' south polar geysers,
and entering the E-ring.

"Both the new ring and the unexpected structures in the E
ring should provide us with important insights into how moons
can both release small particles and sculpt their local
environments," said Matt Hedman, a research associate working
with team member Joseph Burns, an expert in diffuse rings, at
Cornell University in Ithaca, N.Y.

In the latest observations, scientists once again see the
bright ghost-like spokes -- transient, dusty, radial
structures -- streaking across the middle of Saturn's main
rings. Capping off the new batch of observations, Cassini
cast its powerful eyes in our direction and captured Earth, a
pale blue orb, and a faint suggestion of our moon. Not since
NASA's Voyager 1 spacecraft saw Earth as a pale blue dot from
beyond the orbit of Neptune has Earth been imaged in color
from the outer solar system.
 
"Nothing has greater power to alter our perspective of
ourselves and our place in the cosmos than these images of
Earth we collect from faraway places like Saturn," said
Carolyn Porco, Cassini imaging team leader at the Space
Science Institute, Boulder, Colo. Porco was one of the
Voyager imaging scientists involved in taking the Voyager
`Pale Blue Dot' image. "In the end, the ever-widening view of
our own little planet against the immensity of space is
perhaps the greatest legacy of all our interplanetary
travels."

In the coming weeks, several science teams will analyze data
collected by Cassini's other instruments during this rare
occultation event. The data will help scientists better
understand the relationship between the rings and moons, and
will give mission planners a clearer picture of ring hazards
to avoid during future ring crossings.

Images of the new ring, the E-ring, Enceladus and Earth are
available at: http://www.nasa.gov/cassini ,
http://saturn.jpl.nasa.gov and http://ciclops.org .

The Cassini-Huygens mission is a cooperative project of NASA,
the European Space Agency and the Italian Space Agency. The
Jet Propulsion Laboratory, a division of the California
Institute of Technology in Pasadena, manages the Cassini-
Huygens mission for NASA's Science Mission Directorate,
Washington. The Cassini orbiter and its two onboard cameras
were designed, developed and assembled at JPL. The imaging
team is based at the Space Science Institute, Boulder, Colo.

-end-
Received on Tue 19 Sep 2006 07:37:57 PM PDT