New Discoveries About Saturns Rings

Scientists have found a discontinuous bright ring segment, or arc, in the G ring, which encircles Saturn at about 170,000 kilometres (106,000 miles) from the planet’s centre. This arc is similar to those found around Neptune in images from NASA’s Voyager 2 spacecraft in 1989. Scientists believe that long-lived arcs may have been created from a meteor impact, or that they may be created or maintained by a hidden moon.

The ringlets surrounding the knotted F ring have been shown to be arranged in a spiral structure wound like a spring around Saturn. The density and bending waves, other spiralling structures seen in the main rings of Saturn, move across the rings because of the way that relatively massive ring particles exert a gravitational influence on each other and can all move together. However, the F ring’s spiral structure contains very little mass and appears to originate from material somehow episodically ejected from the core of the F ring and then sheared out due to the different orbital speeds followed by the constituent particles. Dr. Sebastien Charnoz, imaging team associate at the University of Paris, says that the spiral may be caused by moons crossing the F ring and spreading particles around. This may mean that the F ring is unstable.

Small, clump-like features continue to be seen in the same region. These may be loosely bound clumps of material, or tiny moonlets. Repeated sightings will help determine their nature. Clumps should dissipate with time, while moons should remain as they are. At least two of these clump-like objects appear to cross the F ring periodically. One of the objects, S/2004 S6 may be responsible for forming the spiral.