A new study shows that the surface of Saturn’s moon Titan dissolves, and the process could lead to the formation of its lakes.
Scientists have found that the process is similar to that which creates sinkholes on Earth, and as the surface dissolves it may form the lakes and seas which have puzzled researchers.
Titan part of an exclusive celestial club
Titan is the only celestial body in the Solar System, apart from Earth, on which scientists are aware of the presence of surface lakes and seas. Titan’s were spotted by the Cassini space probe.
The surface of Saturn’s moon is incredibly cold, and temperatures reach roughly minus 180 degrees Celsius. As a result liquid methane and ethane, rather than water, form the lakes and seas.
Researchers have discovered seas which measure hundreds of kilometers across, reaching several hundred meters deep. The seas are fed by dendritic channels, which scientists liken to rivers.
Alongside these seas, there are numerous smaller, shallower lakes featuring round edges and steep sides. There are also empty depressions.
Scientists do not believe that the lakes are filled by rivers, but rather by rainfall and the addition of liquids from underneath the surface. It has been noted that some of the lakes fill and empty over the course of the 30-year seasonal cycle on Saturn and Titan.
The formation of the depressions which hold the lakes continues to confuse scientists, but this latest study suggests that they may be similar to “karstic” landforms on Earth.
Similarities between rock formations on Titan and Earth
Such features are the result of the erosion of soluble rocks, including limestone and gypsum, as groundwater and rainfall percolates through them. This erosion provokes the formation of rock formations like sinkholes and caves in areas where the climate is humid, and salt pans where the climate is drier.
The chemistry of the rocks, the rate of rainfall and surface temperature all affect the rate of erosion. Huge differences in each of these factors are observed between Titan and Earth, but now scientists believe that the process itself may be remarkably similar.
Thomas Cornet of the ESA leads a team of researchers who calculated the length of time it would have taken to create these features on Titan, and found that a 100-meter deep depression would form over the course of approximately 50 million years in the polar regions, which receive relatively high amounts of rainfall.
Cornet claims that the “dissolution process occurs on Titan some 30 times slower than on Earth.”