Saturn's moon, Dione, imaged by NASA's Cassini in Feb 2008. (Credit: NASA)
We recently explored Saturn’s walnut-shaped moon, Iapetus, to include its two-toned surface features and equatorial ridge. Now we’ll explore another one of Saturn’s moons that also exhibits unique surface features and the processes that could be responsible for them.
Saturn’s moon, Dione, was discovered by Giovanni Cassini on March 21, 1684, and is a very small moon with a radius of only 349 miles (562 km), and orbits Saturn at an average distance of 234,500 miles (377,400 km), which is approximately the Earth-Moon distance. Also like our own Moon, Dione is tidally locked to Saturn, meaning it always has the same face pointed to its parent planet. Dione also exhibits resonance with two close-by moons: Enceladus and Mimas, meaning for every orbit of Enceladus, Dione orbits twice. The density of Dione is 1.48 times that of liquid water, meaning that approximately one-third of Dione is comprised of silicate rock with the rest being ice.
Chasms on Dione imaged by NASA's Cassini in April 2015. (Credit: NASA/JPL-Caltech/Space Science Institute)
Dione was first photographed in 1980 by NASA’s Voyager spacecrafts, it was imaged up-close for a total of five times by NASA’s Cassini between 2005 and 2015. Since Cassini’s missions ended in 2017, there are currently no active missions exploring Dione, and none are being planned.
What else will we learn about this mysterious rocky-ice moon in the coming years and decades? Only time will tell, and this is why we science!
Laurence Tognetti is a six-year USAF Veteran who earned both a BSc and MSc from the School of Earth and Space Exploration at Arizona State University. Laurence is extremely passionate about outer space and science communication, and is the author of "Outer Solar System Moons: Your Personal 3D Journey".
