Solar Radiation Changes Climate on Titan

Like Earth it has 27 degrees tilt and climatic changes. Titan, the Saturn's moon has been experiencing changing climate due to solar radiation.

For the last 30 years the Saturn's moon is under observations of Dr Athena Coustenis from the Paris-Meudon Observatory in France. Based on the analysis he states that the changing seasons of Titan affect it more than previously thought.

His analysis will be presented at the European Planetary Science Congress in Madrid on Friday 28th September.

"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," said Coustenis.

According to his analysis, the reason of these cycles is solar radiation. Inclined at around 27 degrees and similar to Earth where the sunlight reaches different areas in various intensity due to the tilt. Solar radiation is the dominant energy source for Titan's atmosphere, breaking up the nitrogen and methane present in order to create more complex molecules and acting as the driving force for chemical changes.

"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,"  said Coustenis.

He worked on several data that was gathered from the different mission including Voyager 1 (1980), the Infrared Space Observatory (1997), and Cassini (2004 onwards), complemented by ground-based observations. 

It taken almost 29.5 years for Saturn to orbit the sun and each season spans for around 7.5 years on Titan. So the data has now been gathered for an entire Titan year, summarizing all seasons.

Coustenis explains why it is important to investigate this distant moon: "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."