|Photo of Titan taken by NASA's Cassini spacecraft.|
|Closer image of the cloud.|
|The surface of Titan, taken by|
the Huygens probe.
The Cassini spacecraft took this photo of the Saturn's moon in 2012, which showed a huge cloud over the southern pole of Titan, 300 km above the surface. Scientists have been wondering about this southern polar vortex ever since.
Now they know that this cloud contains frozen particles of toxic cyanide. According to the person who led the study, Remco de Kok of Leiden Observatory and SRON Netherlands Institute for Space Research, the pole is a lot colder than previously suspected, the temperatures being a 100 degrees colder than previous models predicted.
Titan has seasons just like Earth but unlike Earth, Titan's seasons last about 7 years. In 2009 the southern hemisphere began transitioning to autumn and started cooling. Scientists analysed the spectrum of sunlight coming off the cloud and noticed a large difference between the cloud and the surrounding areas. The spectral signature indicated that this cloud consisted of cyanide ice. For cyanide to turn into ice, the temperature needs to be minus 234 degrees Farenheit (minus 148 degrees Celsius). This was a 100 °C colder than expected.
This means that the cooling at the winter poles on Titan happens much quicker.