NASA's Cassini spacecraft has captured images of a high-altitude haze and a vortex materializing at the south pole of Saturn's moon Titan. The vortex is a swirling mass of gas.
Tony Del Genio, a Cassini team member at NASA's Goddard Institute for Space Studies, N.Y. says, "The structure inside the vortex is reminiscent of the open cellular convection that is often seen over Earth's oceans. But unlike on Earth, where such layers are just above the surface, this one is at very high altitude, maybe a response of Titan's stratosphere to seasonal cooling as southern winter approaches. But so soon in the game, we're not sure."
Cassini first saw a "hood" of high-altitude haze and a vortex around the pole in the moon's atmosphere, at Titan's north pole when the spacecraft first arrived in the Saturn system in 2004. At the time, it was northern winter. Multiple instruments have been keeping an eye on the Titan atmosphere above the south pole for signs of the coming southern winter. While the northern hood has remained, the circulation in the upper atmosphere has been moving from the illuminated north pole to the cooling south pole. NASA says this movement appears to be causing downwellings over the south pole and the formation of high-altitude haze and a vortex. You can see an animated GIF of the vortex here
Photo: NASA/JPL-Caltech/Space Science Institute