Toxic Cloud Hovers Over Titan's South Pole

Posted on October 6, 2014

Toxic gas cloud hovering over Titan's south pole

Saturn's largest moon Titan has a giant toxic cloud hovering over its south pole. The discovery was made by scientists analyzing data from NASA's Cassini mission. The cloud contains frozen particles of hydrogen cyanide (HCN). Researchers analyzed the spectrum of sunlight reflected by Titan's atmosphere to determine the elements and compounds present.

Titan is the only moon with a dense atmosphere. The moon experiences seasons that last about seven Earth years. The massive cloud hangs about 200 miles (300 kilometers) above the surface of Titan. Researchers say the cloud, or polar vortex, is an effect of the change of seasons on Titan.

Remco de Kok of Leiden Observatory and SRON Netherlands Institute for Space Research is the lead author of the study. He says the discovery indicates that Titan's southern hemisphere is cooling faster than astronomers realized.

De Kok also says, "The light coming from the polar vortex showed a remarkable difference with respect to other portions of Titan's atmosphere. We could clearly see a signature of frozen HCN molecules."

Temperatures have to be very cold for HCN to be form frozen particles. The astronomers say the finding indicates the the atmospheric temperature of Titan has to be as cold as minus 234 degrees Farenheit (minus 148 degrees Celsius). This is much colder than previous theoretical models predicted for Titan's atmosphere.

A research paper on Titan's giant toxic cloud was published here in the journal Nature.

Photo: NASA/JPL-Caltech/ASI/University of Arizona/SSI/Leiden Observatory and SRON