Titan, Saturn’s largest moon is an alien world that is covered in a thick atmosphere of methane. Methane acts like rain on Titan creating clouds and fog as well as rainstorms and plentiful lakes.
Where these features have come from is a mystery to scientists. Recently a computer model of Titan’s atmosphere and methane cycle has been developed that explains many of the phenomena in a simple way.
One oddity that stood out was Titan’s methane lakes that cluster around its poles. The second thing about the methane distribution is that at areas of low latitudes the equator is known to be dry lacking lakes and regular precipitation. But when the Huygens probe landed on Titan in 2005 it saw channels that were carved out by possible liquid run off from rain. The last mystery was the clouds observed over the past 10 years during summer in the southern hemisphere.
The model suggests that methane exists in lakes around the polls because the sunlight there is weaker on average. Energy from the sun normally evaporates liquid methane on the surface but since there is less sunlight at the polls it is easier for liquid methane to exist . But why are there more lakes in the northern hemisphere? The model suggests that Titan’s elongated orbit means that Titan is farther from the Sun when it’s summer in the Northern Hemisphere. Titan therefore spends more time at the farther end of its orbit. This makes the northern summer longer than the southern summer and therefore the rainy season lasts longer in the Northern Hemisphere.
The drying equator is explained by the model. It suggests that there are large downpours every so often and not continual rain so it seems like it is quite dry at the equator but it is actually not the case .
The model is three-dimensional and simulates Titan’s atmosphere for 135 Titan years which is roughly equivalent to 3000 years on Earth and the simulation is also giving predictions for future rainfall and therefore can be checked.