Monday, September 27, 2010

Saturn, in Infrared


This false-color composite image, constructed from data obtained by NASA's Cassini spacecraft, shows Saturn's rings and southern hemisphere. The composite image was made from 65 individual observations by Cassini's visual and infrared mapping spectrometer in the near-infrared portion of the light spectrum on November 1, 2008. The observations were each six minutes long.

In this image constructed from data collected in the near-infrared wavelengths of light, scientists designated blue to indicate sunlight reflected at a wavelength of 2 microns, green to indicate sunlight reflected at 3 microns and red to indicate thermal emission at 5 microns. Saturn's rings reflect sunlight at 2 microns, but not at 3 and 5 microns, so they appear deep blue. Saturn's high altitude haze reflects sunlight at both 2 and 3 microns, but not at 5 microns, and so it appears green to blue-green. The heat emission from the interior of Saturn is only seen at 5 microns wavelength in the spectrometer data, and thus appears red. The dark spots and banded features in the image are clouds and small storms that outline the deeper weather systems and circulation patterns of the planet. They are illuminated from underneath by Saturn's thermal emission, and thus appear in silhouette.

Photo credit: NASA/JPL/University of Arizona/University of Leicester

Note: For similar images and a movie that highlight Saturn's Auroras Australis, see PIA13402: Glowing Southern Lights,
PIA13403: Four Aurora Snapshots
and PIA13404: Dancing Southern Lights of Saturn. A small Quicktime movie of the auroras can be watched here.

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