Seasons On Titan Affect Its Atmosphere Dramatically

Titan, Saturn's largest moon has a magnificent environment. It has lakes of liquid hydrocarbons, nitrogen atmosphere and methane clouds. It's the only satellite that has a dense atmosphere and it experiences dramatic changes every season.

The research, published in the journal Icarus, observed that winters take hold quickly. Winter is now beginning to take its grip on Titan's southern hemisphere and a strong, whirling vortex has developed over the South Pole. All this data has been gathered by Cassini spacecraft that has been observing the Saturnian system since the last 12 years. Cassini is a joint mission by ESA-NASA.

"Cassini's long mission and frequent visits to Titan have allowed us to observe the pattern of seasonal changes on Titan, in exquisite detail, for the first time," explained team leader Dr Athena Coustenis, of the Paris Observatory, in a statement.

According to IFL Science, the scientists have observed a pole-to-pole system of circulation. Warm gases rise from the summer pole and fall drastically at the winter pole causing a large-scale inversion that was witnessed by the spacecraft in 2009 during the equinox. Seasons take much longer to change on Titan in comparison to Earth.

The seasonality of Titan basically depends on several global factors but the scientists have noticed that the two hemispheres of the moon react differently to the change of seasons. The beginning of winter season in the southern hemisphere caused the temperature to drop rapidly by 40 degrees Celsius (72 degrees Fahrenheit) whereas the northern hemisphere, that was observing spring at the same time, stayed unchanged for the first five years.

Polar vortex started just few months after the equinox. Within this amusing atmospheric phenomenon that is safe from all ultraviolet radiations of the sun, complex molecules could be formed. Titan receives only 1 per cent of the sunlight that our Earth gets. However, the moon's dense atmosphere creates a greenhouse effect that makes it warmer than expected. The moon is still significantly below the freezing point.

"As we count down to the end of the Cassini mission in September 2017, a consistent picture of Titan's middle and upper atmospheres is emerging," said Coustenis. "The 13-year total mission duration will, in the end, provide us with coverage of almost half a Titan year and provide an even deeper understanding of Titan's seasonal variability."