Thursday, May 11, 2017

Cassini Looks at Saturn

After orbiting and capturing images of Saturn and its moons since 2004, Cassini’s mission will come to a close in September with a plunge into the planet’s atmosphere, which will destroy the spacecraft.

May 6, 2012 Titan, Saturn’s largest moon, passes in front of the planet in an image taken by the Cassini spacecraft. NASA via AP

July 19, 2013 A natural-color image of Saturn from space, the first in which the planet, its moons and rings, and Earth, Venus and Mars all are visible. The image captures 404,880 miles across Saturn and its inner ring system, including all of its rings out to the E ring, which is Saturn’s second outermost ring. NASA/JPL-Caltech/SSI via Reuters

Jan. 18, 2005 The moon Mimas drifts along in its orbit against the azure backdrop of Saturn’s northern latitudes. The long, dark lines on the atmosphere are shadows cast by the planet's rings. Saturn’s northern hemisphere is now relatively cloud-free, and rays of sunlight take a long path through the atmosphere. This results in sunlight being scattered at shorter, bluer wavelengths, thus giving the northernmost latitudes their bluish appearance at visible wavelengths. NASA/JPL/Space Science Institute via AP

Oct. 27, 2007 The moon Enceladus appears as a white disk across the unilluminated side of Saturn’s rings. NASA/AP

April 13, 2017 An enhanced-color view of the southern latitudes on Saturn’s moon Enceladus featuring bluish “tiger stripe” fractures that rip across the south polar region. NASA/JPL-Caltech via European Pressphoto Agency

July 20, 2016 This false-color view shows clouds in Saturn’s northern hemisphere. This view was made using images taken by Cassini’s wide-angle camera using a combination of spectral filters sensitive to infrared light at 750, 727 and 619 nanometers. NASA/JPL-Caltech/Space Science Institute/Kevin M. Gill 

The aftermath of a rare massive storm on Saturn. Data reveal record-setting disturbances in the planet’s upper atmosphere long after the visible signs of the storm abated, in addition to an indication the storm was more forceful than scientists previously thought. These red, orange and green clouds (false color) in Saturn’s northern hemisphere indicate the tail end of the massive 2010-2011 storm. NASA via European Pressphoto Agency

Why does Saturn look like it’s been painted with a dark brush in this infrared image, but the moon Dione looks untouched? The answer is methane. This image was taken in a wavelength that is absorbed by methane. Dark areas seen here on Saturn are regions with thicker clouds, where light has to travel through more methane on its way into and back out of the atmosphere. Because Dione doesn’t have an atmosphere rich in methane the way Saturn does, it does not experience similar absorption — the sunlight simply bounces off its icy surface. NASA/JPL-Caltech/Space Science Institute

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