AstroTalk Episode September 22, 2016

An Impossible Cloud Forms on Titan - Again

3:02pm - 3:32pm

Scientists working on the Cassini Mission in the Saturn system have discovered an impossible cloud on Saturn's largest moon Titan. A similar type ice cloud was found decades ago by the Voyager 1 Spacecraft. At that time, V1 scientists were puzzled by the fact that the cloud contained less than 1% of the dicyaniacetylene gas that was needed in order for the cloud to condense. At that time, scientists believed that V1's instruments may not have been sensitive enough to detect the gas. The same thing has happened again: just this week, scientists that work with the Cassini spacecraft have found less than 1% of the gas they thought would be needed in order for the cloud to condense. Clouds are thought to form on Titan in the same way that they form on Earth: through the condensation of gases in a evaporation/condensation cycle. Instead of water, the gas in Titan's atmosphere is methane. This puzzling occurrence of the formation of the cloud has led to another theory: the cloud on Titan forms through a similar type of solid-state chemical process that occurs over the N & S poles on Earth. The polar stratospheres on Titan and Earth could not be more different, so Titan has yielded another surprise. It seems that the underlying physical processes in Titans's and Earth's atmospheres have led to analogous cloud chemistry in both places.