The Cassini Imaging Team discovered Methone (pronounced me-thoh-nee) on June 1, 2004. This tiny moon orbits between two of Saturn's mid-sized icy moons, Mimas and Enceladus, at a radius of about 194,000 kilometers (120,456 miles) from its planet. Astronomers have suggested two differing theories to explain the presence of Methone and two other small sister moons, Pallene and Anthe. The first theory indicates that the three little moons may have fragmented off of either Mimas or Enceladus. The second theory, on the other hand, suggests that all five moons--the three small moons and the two mid-size ones--may be the sad remnants of a larger menagerie of moons that floated around in that area--which is situated close to Saturn. Methone orbits its gigantic parent planet in 24 hours.
"This is the closest we've come, so far, to identifying a place with some of the ingredients needed for a habitable environment. These results demonstrate the interconnected nature of NASA's science missions that are getting us closer to answering whether we are indeed alone or not," commented Dr. Thomas Zurbuchen in an April 13, 2017 NASA Press Release. Dr. Zurbuchen is associate administrator for NASA's Science Mission Directorate at Headquarters in Washington D.C.
Jupiter, along with its beautiful ringed sister planet, Saturn, are the gas-giant duo of our Sun's family of eight major planets. The other two giant planets--that dwell in our Solar System's outer limits--are Uranus and Neptune. Uranus and Neptune are classified as ice giants, because they carry within them larger cores than Jupiter and Saturn, as well as thinner gaseous envelopes. Jupiter and Saturn may (or may not) contain small, hidden cores, that are heavily veiled by extremely massive, dense gaseous envelopes.