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South Polar Aurora on Saturn
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Caption NASA:"This image of the North Polar Regions of Saturn shows both the Aurora and underlying Atmosphere, seen at 2 different wavelengths of IR light as captured by NASA's Cassini spacecraft.
Energetic particles, crashing into the Upper Atmosphere cause the Aurora, shown in blue, to glow brightly at 4 microns (six times the wavelength visible to the human eye). The image shows both a bright ring, as seen from Earth, as well as an example of bright Auroral Emission within the Polar Cap that had been undetected until the advent of Cassini.
This Aurora, which defies past predictions of what was expected, has been observed to grow even brighter than is shown here. Silhouetted by the glow (cast here to the color red) of the hot interior of Saturn (clearly seen at a wavelength of 5 microns, or seven times the wavelength visible to the human eye) are the clouds and haze that underlie this Auroral Region. For a similar view of the Region beneath the Aurora see PIA09185.
This image is a composite captured with Cassini's Visual and Infrared Mapping Spectrometer. The aurora image was taken in the near-infrared on Nov. 10, 2006, from a distance of about 1 MKM (such as about 659.000 miles), with a phase angle of 157° and a sub-Spacecraft Planetocentric Latitude of 52° North.
The image of the clouds was obtained by Cassini on June 15, 2008, from a distance of approx. 602.000 Km (such as about 374.000 miles) and a sub-Spacecraft Planetocentric Latitude of 73° North".
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