WIRED Space Photo of the Day for October 2014

October 1, 2014: Polar Vortex on Titan NASA/JPL-Caltech/ASI/University of Arizona/SSI/Leiden Observatory and SRON

These two views of Saturn's moon Titan show the southern polar vortex, a huge, swirling cloud that was first observed by NASA's Cassini spacecraft in 2012.

The view at left is a spectral map of Titan obtained with the Cassini Visual and Infrared Mapping Spectrometer (VIMS) on Nov. 29, 2012. The inset image is a natural-color close-up of the polar vortex taken by Cassini's wide-angle camera.

Three distinct components are evident in the VIMS image, represented by different colors: the surface of Titan (orange, near center), atmospheric haze along the limb (light green, at top) and the polar vortex (blue, at lower left).

To the VIMS instrument, the spectrum of the southern polar vortex shows a remarkable difference with respect to other portions of Titan's atmosphere: a signature of frozen hydrogen cyanide molecules (HCN). This discovery has suggested to researchers that the atmosphere of Titan's southern hemisphere is cooling much faster than expected. Observing seasonal shifts like this in the moon's climate is a major goal for Cassini's current extended mission.

Caption: NASA/JPL-Caltech/ASI/University of Arizona/SSI/Leiden Observatory and SRON

NASA/JPL-Caltech/ASI/University of Arizona/SSI/Leiden Observatory and SRON

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