![]() The planet is named for the Roman god of agriculture and wealth, who was also the father of Jupiter. The farthest planet from Earth discovered by the unaided human eye, Saturn has been known since ancient times. Saturn also has dozens of moons.įrom the jets of water that spray from Saturn's moon Enceladus to the methane lakes on smoggy Titan, the Saturn system is a rich source of scientific discovery and still holds many mysteries. Saturn is not the only planet to have rings, but none are as spectacular or as complex as Saturn's. Like fellow gas giant Jupiter, Saturn is a massive ball made mostly of hydrogen and helium. The icy world Enceladus, which sports geysers at its southern pole, contains one, as does the smoggy moon Titan.Saturn is the sixth planet from the Sun and the second-largest planet in our solar system. "Rock-water interactions provide key nutrients and a source of energy, both being essential ingredients for life."ĭione wouldn't be the only Saturnian moon to host an ocean. "The contact between the ocean and the rocky core is crucial," Attilio Rivoldini, co-author of the study, said in a statement. The close contact between water and rock, along with its extensive age, would make it an excellent breeding ground for microbial life. The ocean is tens of kilometers deep and surrounded by a large rocky core.ĭione's ocean would have formed with the moon, remaining liquid over more than 4 billion years. According to a study made by the Royal Astronomical Society of Belgium, gravity data from Cassini flybys could be explained by an ocean 60 miles (100 km) beneath the surface. A subsurface oceanĭione may hide a subsurface ocean beneath its surface. Other contributors to the erosion likely were plasma and E-ring particles, the article noted. The team observed that some of the ejecta rays have been erased over time due to erosion from dark particles (which could be the same material seen on other moons such as Hyperion and Iapetus). Dione's craters have also been studied for signs of change, such as a separate 2016 Icarus study of the ray system of Creusa crater. Ī 2016 presentation at the American Astronomical Society suggested that some of the moons of Saturn, including Dione, could have been hit by debris from a previous generation of moons. Dione also interacts with two of the larger moons of Saturn, Mimas and Enceladus, influencing their orbits. The gravity of the moon keeps two smaller moons, Helene and Polydeuces, locked into the same orbital position as the three travel around Saturn. Like many moons, including Earth's, Dione is tidally locked, with the same side always facing its parent planet. It is equivalent to conditions 300 miles (480 km) above Earth. It is very thin there is just one oxygen ion for every 0.67 cubic inches (11 cubic centimeters). Created by tectonic activity, these fractured areas crisscross the moon, running tens to hundreds of kilometers in length.Ĭassini also detected a wispy oxygen atmosphere on Dione. As dark material fell from the cliffs, they revealed brightly shining ice underneath. NASA's Cassini-Huygens probe took close-up images more than 20 years later that revealed the wisps were ice cliffs. When Voyager 1 surveyed the moon in 1980, it unveiled wispy features on the trailing side. The exceptionally cold temperatures cause the icy surface to behave much like rock. The temperature on the moon averages minus 302 degrees Fahrenheit (minus 186 degrees Celsius). Scientists have speculated that a collision could have spun the moon around - an impactor that created one of the 22-mile (35 km) craters could have had the force to turn the moon - but the fact that it seems to have spun exactly 180 degrees is unusual.ĭione is 1.48 times as dense as water, suggesting that the moon has a dense core surrounded by ice or water. ![]() Dione, however, has a more heavily cratered backside than front. Generally, the leading hemisphere of a body traveling through space plows face-on through debris, and is more heavily cratered. ![]() But Dione is something of a puzzle due to the location of its heavily cratered areas. Geological features, such as craters and cliffs, take their names from people and places in Virgil's "Aeneid." Wisps and cliffsĭione's surface contains both heavily and moderately cratered regions, with some craters as large as 62 miles (100 km).
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