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-- WITH PHOTO -- TO NATIONAL, AND SCIENCE EDITORS:
NASA Cassini Images May Reveal Birth of New Saturn Moon
WASHINGTON, April 14, 2014 /PRNewswire-USNewswire/ -- NASA's Cassini
spacecraft has documented the formation of a small icy object within
the rings of Saturn that may be a new moon, and may also provide clues
to the formation of the planet's known moons.
Images taken with Cassini's narrow angle camera on April 15, 2013 show
disturbances at the very edge of Saturn's A ring -- the outermost of
the planet's large, bright rings. One of these disturbances is an arc
about 20 percent brighter than its surroundings, 750 miles (1,200
kilometers) long and 6 miles (10 kilometers) wide. Scientists also
found unusual protuberances in the usually smooth profile at the
ring's edge. Scientists believe the arc and protuberances are caused
by the gravitational effects of a nearby object. Details of the
observations were published online today (April 14, 2014) by the
journal Icarus.
The object is not expected to grow any larger, and may even be falling
apart. But the process of its formation and outward movement aids in
our understanding of how Saturn's icy moons, including the
cloud-wrapped Titan and ocean-holding Enceladus, may have formed in
more massive rings long ago. It also provides insight into how Earth
and other planets in our solar system may have formed and migrated
away from our star, the sun.
"We have not seen anything like this before," said Carl Murray of
Queen Mary University of London, and the report's lead author. "We may
be looking at the act of birth, where this object is just leaving the
rings and heading off to be a moon in its own right."
The object, informally named Peggy, is too small to see in images so
far. Scientists estimate it is probably no more than about a half mile
in diameter. Saturn's icy moons range in size depending on their
proximity to the planet -- the farther from the planet, the larger.
And many of Saturn's moons are comprised primarily of ice, as are the
particles that form Saturn's rings. Based on these facts, and other
indicators, researchers recently proposed that the icy moons formed
from ring particles and then moved outward, away from the planet,
merging with other moons on the way.
"Witnessing the possible birth of a tiny moon is an exciting,
unexpected event," said Cassini Project Scientist Linda Spilker, of
NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. According
to Spilker, Cassini's orbit will move closer to the outer edge of the
A ring in late 2016 and provide an opportunity to study Peggy in more
detail and perhaps even image it.
It is possible the process of moon formation in Saturn's rings has
ended with Peggy, as Saturn's rings now are, in all likelihood, too
depleted to make more moons. Because they may not observe this process
again, Murray and his colleagues are wringing from the observations
all they can learn.
"The theory holds that Saturn long ago had a much more massive ring
system capable of giving birth to larger moons," Murray said. "As the
moons formed near the edge, they depleted the rings and evolved, so
the ones that formed earliest are the largest and the farthest out."
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL, a division of
the California Institute of Technology, manages the mission for NASA's
Science Mission Directorate in Washington.
To view an image of the Saturn ring disturbance attributed to the new
moon, visit:
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18078
For more information about Cassini, visit:
Logo - http://photos.prnewswire.com/prnh/20081007/38461LOGO
SOURCE NASA
-0- 04/14/2014
/CONTACT: Dwayne Brown, Headquarters, Washington, 202-358-1726, dwayne.c.brown@nasa.gov; or Jane Platt, Jet Propulsion Laboratory, Pasadena, Calif., 818-354-0880, jane.platt@jpl.nasa.gov
/Photo: http://photos.prnewswire.com/prnh/20081007/38461LOGO
PRN Photo Desk photodesk@prnewswire.com
/Web Site: http://www.nasa.gov
CO: NASA
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