Chasms on Dione

NASA's Jet Propulsion Laboratory Press Release

18 August 2015 Astronomy Now

Image credit: NASA/JPL-Caltech/Space Science Institute.
Image credit: NASA/JPL-Caltech/Space Science Institute.
While not bursting with activity like its system sister Enceladus, the surface of Saturn’s moon Dione is definitely not boring. Some parts of the surface are covered by linear features, called chasmata, which provide dramatic contrast to the round impact craters that typically cover moons.

The bright network of fractures on Dione (698 miles or 1123 kilometres across) was seen originally at poor resolution in Voyager images and was labeled as “wispy terrain.” The nature of this terrain was unclear until Cassini showed that they weren’t surface deposits of frost, as some had suspected, but rather a pattern of bright icy cliffs among myriad fractures. One possibility is that this stress pattern may be related to Dione’s orbital evolution and the effect of tidal stresses over time.

This view looks toward the trailing hemisphere of Dione. North on Dione is up. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on 11 April 2015.

The view was acquired at a distance of approximately 68,000 miles (110,000 kilometres) from Dione. Image scale is 2,200 feet (660 meters) per pixel.

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A brighter Saturnian moon

18 November 2015 Astronomy Now

Although Saturn’s moons Dione (near) and Enceladus (far) are composed of nearly the same materials, Enceladus has a considerably higher reflectivity than Dione. As a result, it appears brighter against the dark night sky. This image was taken by NASA’s Cassini spacecraft in visible light with the narrow-angle camera on 8 September 2015.