Learn About the Solar System

With the GRAIL data, the astronomers were able to map the gravity field both in and around over 1,200 craters on the lunar far side. This region--the lunar highlands--is our Moon's most heavily cratered, and therefore oldest, terrain. Heavily cratered surfaces are older than smoother surfaces that are bereft of craters. This is because smooth surfaces indicate that more recent resurfacing has occurred, erasing the older scars of impact craters. "Titan is a very active moon. We already know that about its geology and exotic hydrocarbon cycle. Now we can add another analogy with Earth and Mars: the active dust cycle, in which organic dust can be raised from large dune fields around Titan's equator," Dr. Sebastien Rodriguez explained in a September 24, 2018 NASA Jet Propulsion Laboratory (JPL) Press Release. Dr. Rodriguez is an astronomer at the Universite Paris Diderot, France, and the paper's lead author. The JPL is in Pasadena, California. 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.