Like some giant beast’s great blue eye Saturn’s north polar vortex appears to glare up at Cassini’s wide-angle camera in this image, a color-composite made from raw images acquired in red, green, and blue visible light wavelengths on February 13, 2017.
The vortex, an 1,800-mile-wide circular storm spinning around Saturn’s pole, lies at the center of an even larger structure: Saturn’s hexagon, a curiously geometric (but quite explainable) jet stream surrounding its north pole. Three sides of the hexagon can be seen above.
This isn’t the best view of Saturn’s vortex that Cassini has captured (that would be this) but it certainly highlights the striking color variations of the feature, which give us a look deep into Saturn’s violent atmosphere.
Here’s another look at the same structure from a slightly different angle, also on Feb. 13, 2017:
Saturn’s hexagon is a particular favorite of mine, as it was featured in my very first blog post here on Lights in the Dark waaaaaay back on Feb. 12, 2009—just four days over eight years ago! Since that time more and more of Saturn’s pole has been illuminated as northern summer solstice approaches during its nearly 30-year-long orbit.
Cassini arrived at Saturn in 2004 during its northern winter and has observed seasonal changes through spring equinox and into summer; solstice at Saturn is on May 24, 2017. Sadly, Cassini won’t quite make it to four months past solstice—its grand finale dive into Saturn is scheduled for Sept. 15, 2017.
ADDED 3/30/17: New views of the north vortex have come in from Cassini and here are color versions of those too. The blue color of the vortex has been getting bolder and bolder; this is a result of sunlight being scattered within the relatively calm, clear “eye of the storm.” It’s basically a circular pool of clear air we’re looking into, illuminated by the Sun and dotted with a few bright white clouds. Super cool!