Evrim Yazgin
Cosmos science journalist
It turns out, even if you could withstand the -179°C temperatures and breathe the atmosphere, you wouldn’t want to surf the waves of Saturn’s moon Titan.
Titan’s lakes have waves only a few millimetres high and rip tides, according to new research published in Nature Communications. The researchers also report evidence of tidal currents.
The new study follows another published last month which used computer simulations to lend credence to the suggestion that Titan’s lakes and seas have waves.
Apart from Earth, Titan is the only planetary body in the solar system known to have active rivers, lakes and seas. But the liquid in these bodies is not water. Titan’s low surface temperature means that the liquids on its surface are hydrocarbons methane and ethane.
NASA’s Cassini spacecraft, which explored Titan from 2004 to 2017, confirmed the existence of Titan’s lakes in 2007. But as the data from Cassini continues to be analysed, more information is being gleaned about this Earth-like, frigid world and its seas.
The authors of the new paper based their findings on examinations of Cassini’s bistatic radar data from Titan’s polar seas taken between 2014 and 2016. Unlike other probing techniques, the bistatic radar allows researchers to examine only the surface of the liquid, not the entire liquid column.
They report that Titan’s seas – named Kraken, Ligeia and Punga Mare – might have different compositions, writing that these compositions are “consistent with a latitudinal dependence in the methane-ethane mixing-ratio”.
The researchers assessed the “roughness” of the liquid surfaces – an indication of ripples on the surface of Titan’s seas.
Roughness was low overall, indicating waves of less than 3mm in height. However, roughness increased “in coastal areas, near estuaries and inter-basin straits, perhaps indicating active tidal currents,” the authors say.
In these areas, waves are estimated to reach 3.6–5.2mm in height.
On Earth, strong and variable tidal currents where tidal flow is constricted in inlets and at the mouths of estuaries result in dangerous “rip tides” or “tidal rip”: narrow, strong currents that head out to sea.
