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Three lakes were found on 2 October, during Cassini鈥檚 first radar pass of Titan鈥檚 south polar region. It is currently summer on the moon鈥檚 southern hemisphereRadar images from seven Cassini flybys of Titan鈥檚 north polar region have been stitched together to create this mosaic

Another misty morning in Xanadu. At -179 掳Celsius, this bright continent on Saturn鈥檚 largest satellite, Titan, is much too cold for liquid water. Instead, the morning mist consists of tiny droplets of methane. The daily drizzle may be the result of prevailing easterly winds that are driven upwards by the mountainous region, causing cooling and condensation, a new study suggests.

The early-morning methane drizzle neatly explains a daily increase in the opacity of the lowest portion of Titan鈥檚 atmosphere, detected in spectroscopic observations with the Keck telescope in Hawaii, US, and the Very Large Telescope in Chile.

According to a team from the University of California in Berkeley led by M谩t茅 脕d谩mkovics, the drizzle may even be responsible for why Xanadu is so bright. It could be 鈥渞insing the bright surface鈥� of dark hydrocarbons, the researchers say.

Meanwhile, the Cassini spacecraft has started to explore Titan鈥檚 south polar region with its radar and has found the first lakes there (see image above right). It had already mapped about 60% of the moon鈥檚 north polar region and turned up about 400 lakes and seas there (see image below right and watch a ).

鈥淭itan is indeed the land of lakes and seas,鈥� says Rosaly Lopes, a member of Cassini鈥檚 radar team at NASA鈥檚 Jet Propulsion Laboratory in Pasadena, California, US. 鈥淚t will be interesting to see the differences between the north and south polar regions.鈥�

Cassini scientists believe the lakes fill depressions originally formed by volcanism or by the dissolution of rock. Methane and ethane rain is thought to fill the lakes and seas in a process similar to what occurs on Earth.

鈥淭he lakes we are observing on Titan appear to be in varying states of fullness, suggesting their involvement in a complex hydrologic system akin to Earth鈥檚 water cycle,鈥� says Alex Hayes, a graduate student at Caltech who is studying Cassini鈥檚 radar data. 鈥淭his makes Titan unique among the extraterrestrial bodies in our solar system.鈥�

Both 脕d谩mkovics and Lopes presented their results today at a meeting of the American Astronomical Society鈥檚 Division for Planetary Sciences in Orlando, Florida, US.

Journal reference: (doi: 10.1126/science.1146244)

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