Cassini spots massive ice cloud above Titan's south pole
NASA's Cassinispacecraft has revealed the presence of an enormous cloud locatedaround the Saturnian moon Titan's southern polar region. Thediscovery comes as the spacecraft nears the end of its mission, whichhas stretch over a decade-long mission, and characterizes the ringedgiant and its moons in spectacular fashion.
Titan's winter seasonlasts for an impressive seven and a half Earth-years. This hasallowed Cassini to observe the slow passing of the enigmatic moonperiodically since arriving around Saturn in June 2004
The cloud seenshrouding the southern extremes of the enigmatic moon was createdthrough a process unlike anything that occurs here on Earth. On ourplanet, rain clouds are created when water vapour rising throughEarth's atmosphere rises to an altitude with the correct temperatureand pressure to induce condensation.
Whilst some clouds arecreated through a similar process in Titan's atmosphere, the polarcloud is believed to have developed via a different method. Asmog-like, icy cloud of gasses most likely comprised of hydrocarbonsand nitrates, which was transferred from the warmer northernhemisphere to the colder south falls through Titan's atmosphere.
As the gasses descend,they gradually condense to form the highly layered cloud located in astable atmospheric region in the planet's low-mid stratosphere, whichis observable by Cassini's Composite Infrared Spectrometer.
By analyzing Cassinidata, NASA scientists are able to deduce the severity of the weatherthe moon's winter. It is estimated that temperatures at Titan's southpole could dip beneath -238 ºF(-150 ºC).
"The opportunity tosee the early stages of winter on Titan is very exciting," statesRobert Samuelson, a researcher at NASA's Goddard Space Flight Center,Greenbelt, Maryland. "Everything we are finding at the south poletells us that the onset of southern winter is much more severe thanthe late stages of Titan's northern winter."
Moving forward, theCassini spacecraft will continue to make periodic observations ofTitan's atmosphere prior to the termination of its solstice missionin 2017.