Pictured above: Artistic impression of how a lake on Titan would look like.
According to the data gathered by NASA’s Cassini probe, the ocean on Saturn’s moon Titan (the largest of the planet’s moons) has a very high concentration of salts. The probe only gathered gravitation data and didn’t perform a full chemical analysis, obviously, but the initial data suggest that the ocean has a very high density. Since salted water has a higher density than regular water, the scientists’ best guess so far is that the ocean on Titan must therefore be quite salty, possibly as salty as the Dead Sea on Earth.
The Dead Sea contains a combination of sulfur, sodium and potassium salts, dissolved throughout it, and the scientists believe it’s the closest comparison term for Titan’s ocean. The data gathered in the ocean on Saturn’s moon suggest a density high enough to make the scientists guess that it’s a very salty kind of water for Earth’s standards, thus the comparison with the Dead Sea. While the average salinity for our oceans is 3.5%, some parts of the Dead Sea can have salinity as high as 40%.
The ocean on Saturn’s moon is located inside it, since the surface is covered in a thick ice shell enveloping everything. The Cassini probe gathered gravity data over the past two years which helped researchers come up with a more accurate model of the moon. The data suggests that the ice shell varies in thickness across the surface, which means that the ocean inside is probably undergoing a process of freezing as well. That would also decrease the chances for life to develop in the ocean on Saturn’s moon, since it would limit the possible exchanges between the water and the surface.
Another interesting fact provided by the data which Cassini gathered is related to the atmosphere on Saturn’s moon. It apparently contains about 5% methane, which is a mystery, since scientists say that sunlight breaks up this gas quite quickly. The current hypothesis is that a natural process of some sort must be circulating the methane through the atmosphere, making it fall down as rain and rise back up again. The only thing is that for the methane to rise up again, it would require the existence of a few hot spots, which means that the surface of Titan isn’t yet completely frozen.
The Cassini probe which gathered the data about the ocean on Saturn’s moon was launched from Earth in 1997 and entered Saturn’s orbit in 2004. Another probe named Huygens was then dropped on Titan’s surface in January 2005, leading to what we have learned today.