This image of the northern polar region of Saturn shows both the aurora
and underlying atmosphere, seen at two different wavelengths of infrared
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 1,061,000 kilometers (659,000 miles),
with a phase angle of 157 degrees and a sub-spacecraft planetocentric
latitude of 52 degrees north. The image of the clouds was obtained by
Cassini on June 15, 2008, from a distance of 602,000 kilometers (374,000
miles) and a sub-spacecraft planetocentric latitude of 73 degrees north.
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages
the mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter was designed, developed and assembled at JPL. The Visual
and Infrared Mapping Spectrometer team is based at the University of
Arizona.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping
spectrometer team homepage is at http://wwwvims.lpl.arizona.edu.