The Challenging Depths of Titan's Seas

New analyses of Cassini radar altimeter data (Poggiali et al., 2020, https://doi.org/10.1029/2020JE006558) measure the 85 m depth and brackish (moderately ethane-poor) composition of Moray Sinus, an estuary at the northern margin of Titan's largest sea, Kraken Mare. No bottom echo was detected on Kraken itself, suggesting it is either very deep, ethane-rich, or both. Plain Language Summary Saturn's moon Titan is the only world apart from Earth with surface seas. In Titan's case, these are made of methane and ethane, which are components of natural gas on Earth. Methane is analogous to water on Earth, being an abundant vapor that forms clouds and rain and flows in rivers, while ethane is analogous to salt. New analysis of radar data from the Cassini mission shows that Moray Sinus, an inlet in the northern margin of Kraken Mare, Titan's largest sea, is surprisingly deep. The transparency of the liquid to the radar signal suggests it is also quite fresh, that is, ethane-poor. But no radar echo was found over Kraken itself, implying it is either richer in ethane, or very deep, or both. This is an important clue as to how Titan's seas are mixed and how Titan's climate works.

Automated summary

New analysis of Cassini radar altimeter data reveals the depth and composition of Moray Sinus, an inlet at the northern margin of Titan's largest sea, Kraken Mare. The absence of a bottom echo on Kraken Mare suggests it may be very deep, ethane-rich, or both. This research provides insight into Titan's seas and climate.