Astronomy Picture of the Day
August 18, 2015

Fractures and Icy Cliffs on Dione
Fractures and Icy Cliffs on Dione

Credits: NASA/JPL/Space Science Institute - Credits for the additional process. and color.: Dr Paolo C. Fienga/LXTT/IPF

Even though it is not bursting with activity, like its System Satellite Enceladus, the Surface of Dione is definitely not boring. As a matter of fact, some parts of said Surface are covered by Linear Features, called "Chasmata" (---> sing.: Chasma, such as "Abyss"), which provide dramatic contrast to the round Unnamed Impact Craters that typically cover the Gas-Giant Planets' moons.


The bright network of Fractures that are visible on on Dione (about 698 miles, or approx. 1123,31932 Km across) was originally sen - at poor resolution - in some of the NASA - Voyager Probes' images and was labeled as "Wispy Terrain." The nature of this terrain was unclear until the NASA - Cassini Spacecraft showed that they weren't Surface Deposits of Frost and Ice (like some Planetary Scientist had suspected), but rather a pattern of bright Icy Cliffs located among a myriad of Fractures. However, one possibility is that this pattern of Fractures and Cliffs may be related to Dione's orbital evolution and the subsequent effect of Tidal Stresses over time.


This view looks toward the Trailing Hemisphere of Dione, and North is up. The image was taken in Visible Light with the NASA - Cassini Spacecraft Narrow-Angle Camera on April 11, 2015. The image was acquired at a distance of approximately 68.000 miles (such as about 109.435,12 Km) from Dione. Image scale is roughly 2200 feet (meaning about 670,56 meters) per picture element (---> pixel).


This frame (which is an Original NASA - CASSINI Spacecraft's b/w and NON Map-Projected image published on the NASA - Planetary Photojournal with the ID n. PIA 18327) has been additionally processed, contrast enhanced, magnified to aid the visibility of the details, Gamma corrected and then colorized - according to an educated guess (or, if you wish, an informed speculation) carried out by Dr Paolo C. Fienga - in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Cassini Spacecraft and then looked outside, towards the Saturnian moon "Dione"), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among other things, the existence of different Elements (Minerals) present on the Surface of Dione, each having a different Albedo (---> Reflectivity) and Chemical Composition.


Note: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of Dione - as it is in this frame - would appear, to an average human eye, a little bit lower than it has been shown (or, better yet: interpreted) here.



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