Saturn’s moon Titan has been observed in detail for the past 30 years, including an entire solar orbit for this ‘distant world.’ Researcher Dr Athena Coustenis from the Paris-Meudon Observatory in France has finished an analysis of the data that was gathered during this time period and has found that the changing seasons on Titan exert much more of an influence than had previously been thought.
Dr Coustenis explains: “As with Earth, conditions on Titan change with its seasons. We can see differences in atmospheric temperatures, chemical composition and circulation patterns, especially at the poles. For example, hydrocarbon lakes form around the north polar region during winter due to colder temperatures and condensation. Also, a haze layer surrounding Titan at the northern pole is significantly reduced during the equinox because of the atmospheric circulation patterns. This is all very surprising because we didn’t expect to find any such rapid changes, especially in the deeper layers of the atmosphere.”
These seasonal cycles seem to be mainly caused by solar radiation, as on Earth. The Europlanet news release states: “This is the dominant energy source for Titan’s atmosphere, breaking up the nitrogen and methane present to create more complex molecules, such as ethane, and acting as the driving force for chemical changes. Titan is inclined at around 27 degrees, similar to the Earth, meaning that the cause of seasons – sunlight reaching different areas with varying intensity due to the tilt – is the same for both worlds.”
Dr Coustenis says: “It’s amazing to think that the Sun still dominates over other energy sources even as far out as Titan, over 1.5 billion kilometres from us.”
These conclusions were drawn from data that was gathered over several different missions, “including Voyager 1 (1980), the Infrared Space Observatory (1997), and Cassini (2004 onwards), complemented by ground-based observations.” The seasons on Titan last around 7.5 years, and its ‘year’, the time it takes to orbit the Sun, is around 29.5 years. So, since observations began, data has now been gathered and now analyzed for an entire Titan year, ‘encapsulating’ all of Titan’s seasons.
Dr Coustenis explains further what the purpose of investigating the distant moon is: “Titan is the best opportunity we have to study conditions very similar to our own planet in terms of climate, meteorology and astrobiology and at the same time a unique world on its own, a paradise for exploring new geological, atmospheric and internal processes.”
Source: Europlanet Media Centre
Image Credits: ESA; Cassini-Huygens DISR