The evidence comes from a black-and-white image of the outermost ring captured by the Cassini spacecraft. Scientists noticed a bump or distortion on the edge of the ring which they believe indicates the presence of some kind of object. It is estimated that Peggy may be about half a mile in diameter and it is almost certainly made of ice.
The disturbance in the edge of the ring is 20% brighter than its surroundings and about 1,207km (750 miles) long and 9.7km (six miles) wide. Details were published in the journal Icarus. The significance of the discovery is that the image may have captured the moment of the moon's birth amid the clouds of ice particles making up the rings.
The theory is that because the rings contain so much ice, and because many of Saturn's moons are composed primarily of ice, the rings provide the nursery for new moons before they migrate to more distant orbits.
What happens to Peggy now is not clear. If it continues to orbit inside the rings, it runs the risk of collisions with smaller lumps of ice with the likelihood of the tiny moon disintegrating. However, if Peggy escapes beyond the rings, it will run the gauntlet of drifting through the paths of much larger moons.
In any event, the moon's small size means that if it does migrate beyond the rings, it will be impossible for the scientists to keep track of it.
reporter
Park Sae-jin
swatchsjp@ajunews.com