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Seasonal changes on Saturn seen by Cassini

Charles Black, Founder and CEO of Sen
05 September 2012, 23:00 UTC

Sen— Four new pictures of Saturn and its largest moon Titan as seen by NASA’s Cassini spacecraft have been unveiled. Just as seasonal changes on Earth cause colour changes in nature, these new images reveal that Saturn’s northern and southern hemispheres switch colours as the seasons change.

The stunning images were processed by the Cassini Imaging Central Laboratory for Operations (CICLOPS) under the supervision of Cassini imaging team leader Dr Carolyn Porco, who first noticed the colours changing with the seasons.

When Cassini arrived at Saturn in 2004, the northern hemisphere of Saturn was blue because it was winter there. Now with the seasons changing, winter is fleeing the northern hemisphere for the southern hemisphere, and this is visible in the blue hue now appearing in the south.

Cassini image of Titan obscured by Saturn's rings

A blue hue appears in Saturn's southern hemisphere as winter approaches. Credit: NASA/JPL-Caltech/SSI 

Three of the images show Saturn’s largest moon, Titan, and the recently discovered vortex in the atmosphere at the south pole. The visible light cameras on Cassini have been monitoring a strange yellow haze in the detached haze layer at Titan’s south pole since 27 March. The visual and infrared spectrometers then detected clouds building up in the region on 22 May. When Cassini flew by Titan on June 27, 2012, it was found that the vortex is spinning faster than the moon itself is rotating.

The views of the vortex are only possible because Cassini is on a new orbit that is tilted, which enables it to get a better look at the polar regions of both Saturn and its moons.

"Cassini has been in orbit now for the last eight years, and despite the fact that we can't know exactly what the next five years will show us, we can be certain that whatever it is will be wondrous," explains Carolyn Porco.

The south polar vortex is visible in this image. Credit: NASA/JPL-Caltech/SSI

Cassini is currently in its second mission extension, which has been called the Solstice Mission, and monitoring the seasonal changes on the ringed planet is one of the main objectives at the moment.

"It is so fantastic to experience, through the instruments of Cassini, seasonal changes in the Saturn system," said depute project scientist Amanda Hendrix. "Some of the changes we see in the data are completely unexpected, while some occur like clockwork on a seasonal timescale. It's an exciting time to be at Saturn."

 The night side of Titan reveals a ring of colour. Credit: NASA/JPL-Caltech/SSI

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

Cassini was launched in 1997 and entered Saturn's orbit in 2004. The Huygens space probe landed successfully on Titan in 2005. Cassini continues to provide much information and stunning images of Saturn, its rings and its moons.

The Cassini Imaging Central Laboratory for Operations (CICLOPS) and team leader (Dr Carolyn Porco) are based at the Space Science Institute in Boulder, Colorado.

NASA's Jet Propulsion Laboratory (JPL) based in Pasadena, California, a division of the California Institute of Technology, manages the overall mission for NASA.