How about sending a robotic submarine to Titan? That’s what astronomers at Cornell University would like to do, as they recently published a paper in the JGR: Planets that details their findings on Titan’s largest sea, Kraken Mare.

Titan is Saturn’s largest moon, and it has an atmosphere and liquid lakes. Now, those lakes aren’t full of water; they are full of methane. And Kraken Mare has been found to be 1000 feet deep at its center, which is a great depth for a robotic submarine. The team at Cornell used data from flybys of Cassini to determine both the depth and the composition of Kraken Mare. For some reason, it was the only sea on Titan that had not been measured, and it contains nearly 80% of the moon’s surface liquids.

Amazingly, the Cassini data used was taken during a flyby that was observing Titan for a different sea — Ligeia Mare — where images captured a disappearing and reappearing “Magic Island”. The radar altimeter took depth soundings of both Kraken Mare and Moray Sinus, which is an estuary at the northern end of the sea. Moray Sinus is only 280 feet deep, too shallow for the radar to acquire data useful in determining the composition of the liquid.

However, Kraken Mare’s depth of 1000 feet helped the researchers determine that its composition was similar to that of Ligeia Mare. This was an unexpected result as the expectation was that Kraken Mare, and yes, I’m going to say it over and over as it’s an awesome name, would be more ethane-rich. But no. It’s dominated by methane still, and as we talked about in a story last year, the continued existence of liquid methane on Titan is a bit of a puzzle. Methane in the atmosphere is converted by Titan’s solar light into ethane and should be depleted in the lakes and seas.

So let’s start planning for that robotic submarine and go solve this mystery. 

More Information

Cornell University press release

“The Bathymetry of Moray Sinus at Titan’s Kraken Mare,” V. Poggiali et al., 2020 November 12, JGR: Planets