Astronomy Journal Entry
Saturn's Moon May Have Ring (May 5, 2008)
Artist's view of what Rhea's ring may look like. The objects within the ring are much larger than scale to make them more visible in the drawing. Saturn is seen at upper right. NASA JPL.
Everyone knows about Saturn's famous rings. Astronomers say the planet's moon Rhea could have its very own ring as well.
The Cassini spacecraft found clues of a ring around Saturn's second biggest moon on its flyby in 2005. If the ring is confirmed, Rhea will be the first ringed moon found in the solar system.
A big clue to the ring was Cassini's discovery that Rhea had fewer electrons around it than scientists had expected. They predicted Rhea would be surrounded by thick field of electrons since it's influenced by Saturn's magnetic fields. In theory, these fields act as electron and ion (charged atom) traps.
The presence of a ring would explain the "missing" electrons. Ice particles in the ring may be absorbing the electrons.
