Four days after Cassini took the last images of Titan, it was plunged into the atmosphere of Saturn. Image credit: NASA/JPL-Caltech/Space Science Institute
During NASA’s Cassini mission’s final distant encounter with Saturn’s giant moon Titan, the spacecraft captured the enigmatic moon’s north polar landscape of lakes and seas, which are filled with liquid methane and ethane. They were captured on 11 September 2017. Four days later, Cassini was deliberately plunged into the atmosphere of Saturn.
Punga Mare (390 kilometres, or 240 miles, across) is seen just above the centre of the mosaic, with Ligeia Mare (500 kilometres, or 300 miles, wide) below centre and the vast Kraken Mare stretching off 1,200 kilometres (730 miles) to the left of the mosaic. Titan’s numerous smaller lakes can be seen around the seas and scattered around the right side of the mosaic. Among the ongoing mysteries about Titan is how these lakes are formed.
Another mystery at Titan has been the weather. With its dense atmosphere, Titan has a methane cycle much like Earth’s water cycle of evaporation, cloud formation, rainfall, surface runoff into rivers, and collection in lakes and seas. During Titan’s southern summer, Cassini observed cloud activity over the south pole.