The Bruce Murray Space Image Library
Ratios reveal near-polar structures on Titan
Filed under pretty pictures, Cassini, Titan, Saturn's moons
Special processing has revealed patterns in twilit near-polar terrain in htis view of Titan from March 29, 2007, as Cassini was approaching for the T27 flyby. To create this view, the imaging team ratioed two images taken through different filters. One of the two images was taken in a methane absorption band and mostly reveals details in the lower atmosphere and stratosphere of Titan. The other was taken in a "methane window," a wavelength at which methane gas is relatively transparent, so the surface was more visible, but still hazed by atmospheric effects. Processing the images by dividing one by the other cancels out the brightness variations due to the different angles at which the Sun illuminates the spherical Titan's surface. This processing reveals previously hidden dark patterns near Titan's north pole, which is nearing the end of winter. These areas are actually not receiving any direct sunlight at all; the lighting is only indirect, from sunlight scattered by Titan's thick atmosphere. The dark features may be lakes of liquid methane and ethane, which have recently been revealed in RADAR images of Titan's north polar region.
NASA / JPL-Caltech / SSI
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Original image data dated on or about March 29, 2007
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