Possible Moon Named Peggy Forming in One of Saturn's Rings

Posted on April 15, 2014

Peggy is an object in Saturn's A Ring that could be a new moon forming


A possible moon appears to be forming in one of Saturn's rings. A small icy object was captured by NASA's Cassini spacecraft. The object is forming at the outer edge of Saturn's A ring. The object, informally named "Peggy," is about half a mile (1 kilometer) in diameter. It could be in the process of migrating its way out of the ring. This migration idea is one theory for the creation of several of Saturn's other moons. Many of Saturn's 62 known moons are mainly water ice.

Professor Carl Murray from Queen Mary's Astronomy Unit says in a statement, "We hadn't seen anything like this before. 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 theory holds that Saturn long ago had a much more massive ring system capable of giving birth to larger moons. 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 mass of the ring system that produced them has been getting smaller with time."

The L.A. Times reports that Peggy is named after Murray's mother-in-law. Scientists believe Peggy is about as big as it is going to get and could eventually begin to break apart. The research was published here in the journal Icarus.

Photo: NASA/JPL-Caltech/Space Science Institute