The findings represented further evidence about Titan's hydrological cycle, with liquid hydrocarbons raining down from clouds, flowing across its surface and evaporating back into the sky - comparable to Earth's water cycle.
Titan's hydrologic cycle works similarly to Earth's - with one major difference. But Titan is so cold that they behave as liquids, like gasoline at room temperature on our planet. But these lakes are not filled with H2O like here on our planet, but instead, they are made up of liquid methane.
They have noted the presence of dark patches across the northern hemisphere - this was where the methane lakes were. Ethane is slightly heavier than methane, with more carbon and hydrogen atoms in its makeup. "Titan is a really fascinating object in the solar system, and each time we look closely at the information we figure out something rdquo", California Institute of Technology Planetary researcher Marco Mastrogiuseppe explained. "It will give us a much better understanding what lies beneath the icy crust and how it could offer an environment for life to develop". Another odd feature of Titan: one side of the northern hemisphere appeared to be an entirely different world from the other side, at least in terms of hydrology.
"It is as if you looked down on the Earth's North Pole and could see that North America had completely different geologic setting for bodies of liquid than Asia does". And the lakes on Titan's eastern side are vastly different than the big seas with low elevation, canyons and islands on Titan's western side.
And the new measurements show the lakes perched atop big hills and plateaus.
The researchers described landforms akin to mesas towering above the nearby landscape, topped with liquid lakes more than 100 metres deep comprised mainly of methane. The shape and location of the lakes hints strongly that the lakes are similar to karstic lakes on Earth, where liquid eats away at and eventually collapses the bedrock around it. Titan's Deep Lakes Atop Mountains In the first paper, a Mastrogiuseppe-led team reveal the results of their investigations on Titan's lakes. These lakes appear in earlier Cassini data and disappear later on. That study was led by Shannon MacKenzie of the Johns Hopkins University Applied Physics Lab, and included co-authors Sam Birch, Ph.D.
"One possibility is that these transient features could have been shallower bodies of liquid that over the course of the season evaporated and infiltrated into the subsurface".
On its last closest approach to Titan, on 22 April 2017, Cassini flew over the northern hemisphere of the moon and fired up its radar to probe the depths of the lakes there for the first time.
The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency.