lundi 27 juillet 2015

Bright Basin on Tethys












NASA - Cassini Mission to Saturn patch.

July 27, 2015

Bright Basin on Tethys

With the expanded range of colors visible to Cassini's cameras, differences in materials and their textures become apparent that are subtle or unseen in natural color views. Here, the giant impact basin Odysseus on Saturn's moon Tethys stands out brightly from the rest of the illuminated icy crescent. This distinct coloration may result from differences in either the composition or structure of the terrain exposed by the giant impact. Odysseus (280 miles, or 450 kilometers, across) is one of the largest impact craters on Saturn's icy moons, and may have significantly altered the geologic history of Tethys.

Tethys' dark side (at right) is faintly illuminated by reflected light from Saturn.

Images taken using ultraviolet, green and infrared spectral filters were combined to create this color view. North on Tethys (660 miles or 1,062 kilometers across) is up in this view.

The view was acquired on May 9, 2015 at a distance of approximately 186,000 miles (300,000 kilometers) from Tethys. Image scale is 1.1 mile (1.8 kilometers) per pixel.

Mother and Daughter

In Greek mythology, Dione was the daughter of Tethys, so we should perhaps not be surprised to see the two eponymous moons together.

In reality, the moons Tethys (660 miles or 1062 kilometers across) and Dione (698 miles or 1123 kilometers across) are not mother and daughter in any sense. They are perhaps more like sisters since scientists believe that they formed out of the same disk around an early Saturn.

Dione in this image is the upper moon, while Tethys is the lower.

This view looks toward the anti-Saturn side of Dione. North on Dione is to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 4, 2015.

The view was obtained at a distance of approximately 1.5 million miles (2.4 million kilometers) from Dione. Image scale is 9 miles (14 kilometers) per pixel.

Cassini spacecraft

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Images, Text, Credits: NASA/JPL-Caltech/Space Science Institute/Tony Greicius.

Greetings, Orbiter.ch

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