On Titan, one of Saturn’s moons, a region very similar to the Salar de Etosha, in Nabimia, has been found. Both are shallow lakes that only fill up under certain conditions. They are known as ephemeral lakes.
Until now it was thought that this lake, called Ontario, was permanently filled with liquid methane, ethane and propane, but a new study, published in the journal Icarus , indicates that Ontario is an ephemeral lake that functions just like its equivalents on Earth, only, instead of water, this lake is filled with hydrocarbons.
During the rainy season, the saline bed of the Salar de Etosha (Nabimia) is covered by a layer of water that comes from an underground aquifer. Later, this layer ends up evaporating and leaves a sediment mark. In the same way, Lake Ontario on Titan could be fed by an underground hydrocarbon channel , which sometimes overflows, flooding the depression, and then dries up again.
The team of scientists, from the University of Nantes (France), reached these conclusions after analyzing the observations of the Cassini probe, from the European Space Agency (ESA). The researchers discovered a series of furrows in the lake bed, on the southern shore of the depression, as well as accumulations of sediment around it. “We concluded that the bottom of Lake Ontario had been exposed in that area,” explains Thomas Cornet, one of the authors.
In addition to Earth, Titan is the only other body in the Solar System capable of stably holding liquids on its surface. Titan has its own hydrocarbon cycle, based on the exchange of hydrogen, carbon and nitrogen between its atmosphere, the surface and the subsoil, with many similarities to the water cycle of our planet.
“These results highlight the importance of comparative analyzes in planetary sciences: by identifying familiar geological features in other celestial bodies, as in this case on Titan, we are able to develop hypotheses about their formation,” explained Nicolas Altobelli, project scientist Cassini-Huygens for ESA.
