Possible New Moon Forming Around Saturn
 
April 14, 2014: NASA's Cassini spacecraft has documented the formation of a
small icy object within the rings of Saturn. Informally named "Peggy," the
object may be a new moon. Details of the observations were published online
today by the journal Icarus.
 
"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."
 
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18078
 
This disturbance visible at the outer edge of Saturn's A ring in this image
from NASA's Cassini spacecraft could be caused by an object replaying the
birth process of icy moons.  More
 
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.
 
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.
 
"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.
 
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.
 
"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."
 
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.
 
Credits:
Production editor: Dr. Tony Phillips | Credit: Science@NASA
 
More information:
 
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.
 
 
Regards,
 
Roger

--- D'Bridge 3.99
 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)