http://www.latimes.com/science/sciencenow/la-sci-sn-peggy-new-moon-in-saturn-rings-20140415,0,5141477.story

NASA's Cassini snaps baby picture of Peggy, Saturn's newest moon



The population of moons in orbit around Saturn may be increasing by one -- a 
tiny, icy object that astronomers have nicknamed "Peggy."

NASA's Cassini spacecraft has spotted evidence that a mysterious object perhaps 
half a mile across is disturbing the outer edge of Saturn's large, bright A 
ring. The object's gravity seems to have roughed up the ring's usually smooth 
profile.

As a result, a stretch of the A ring that measures 750 miles long and 6 miles 
wide is now about 20% brighter than it would typically look. The fuzzy blob on 
the A ring's edge was imaged by Cassini's narrow-angle camera exactly one year 
ago, on April 15, 2013.

Peggy, which is believed to have caused this mess, is too small for Cassini to 
see directly. But NASA scientists hope to get a closer look in late 2016, when 
Cassini is scheduled to fly near the A ring.

There's good reason to think Peggy could join the very long list of Saturnian 
moons (a list that includes 53 official moons and nine provisional ones). 
Astronomers have theorized that the moons started out as collections of ice 
from Saturn's hefty rings and then drifted into orbits farther away.

The oldest moons probably formed when the rings were more substantial. By 
coalescing so much material, they grew large and drifted into orbits farther 
away from the planet.

Younger moons, on the other hand, tend to be smaller and closer in. If Peggy is 
indeed a moon, it would certainly seem to be following that pattern.

"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," Carl Murray, an 
astronomer at Queen Mary University of London, said in a statement from NASA. 
"We have not seen anything like this before."

Murray is the lead author of a report on Peggy that was published online Monday 
in the journal Icarus.

Peggy -- named after Murray's mother-in-law, according to reports -- is 
probably as big as it's ever going to get. It might even be coming apart, 
according to NASA. But it may still be able to give scientists clues about how 
Saturn's dozens of other moons came to be.

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