CICLOPS: Cassini Imaging Central Laboratory for OPerationS
A Blue Northern Mystery

A Blue Northern Mystery
PIA 10558

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  Saturn's north pole retains its bluish hue in this true color Cassini image, even as northern winter is coming to an end. The azure blue of Saturn's winter hemisphere during the early Cassini prime mission still remains a puzzle. Over the course of time, the blue color has faded and has been replaced with bands of other hues (see PIA11141).

The north pole is in shadow here, but a portion of its oscillating hexagonal pattern is visible. Storms create the look of a pockmarked surface.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were acquired with the Cassini spacecraft wide-angle camera on Nov. 29, 2008 at a distance of approximately 1.098 million kilometers (683,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 38 degrees. Image scale is 62 kilometers (39 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. 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 imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Equinox Mission visit, and

Credit: NASA/JPL/Space Science Institute
Released: January 16, 2009 (PIA 10558)
Image/Caption Information

Alliance Member Comments
Dragon_of_Luck_Mah_Jonng1971 (Feb 4, 2009 at 7:48 PM):
I suppose either the bluish areas have got lower cloud tops ( so that the uniform haze above them is showing more its blue color ) or the bluish areas are containing clouds with a different chemistry.
There are several large storm systems that generally are rotating clockwise ( I think ) so they are high pressure cells.
The very many smaller systems are stressing the impression that the processes happening there in the atmosphere are very complicated. I think that those ones are both highs and lows. ( lows rotating counter-clockwise )
At the lower right there is a storm system that 'tore' away parts of the yellowish clouds' northern limit into the bluish zone.
This image is a 'snapshot' of Saturnian meteorology.
But there have to be also rising and sinking motions of the ( visible ) atmosphere, if Saturn in that way is similar to Jupiter.
NeKto (Jan 16, 2009 at 8:29 AM):
Could the color differences be from ice crystals or liquid droplets of some kind either melting, sublimating, evaporating or just changing size due to increased exposure to light?