There's a place in the universe where you could surf, but you'd need a very special wetsuit. On Titan, Saturn's largest moon, liquid methane forms waves that shape the shorelines of alien lakes and seas. It's as if the Earth has a distorted twin, where the familiar becomes strangely exotic. Thanks to new simulations and data from Cassini probe, scientists are starting to understand how this frozen world evolves, driven by tides of a liquid we would use for cooking on Earth.
A dive into the space past
Nearly two decades ago, the Cassini probe and its Huygens lander gave us a glimpse beneath Titan's atmospheric veil. It was like lifting the curtain on a surreal spectacle: rivers, lakes and even seas as large as Earth's Great Lakes, but composed of toxic liquids such as methane and ethane. A familiar yet alien landscape, like a Dali painting set in deep space.
For years, scientists have debated the existence of waves on Titan. Some claimed that the seas were smooth as mirrors, others swore they saw ripples on the liquid surface. It was like trying to decide whether Schrödinger's cat was dead or alive without being able to open the box.
Some who have looked for evidence of waves have seen none, and have said: 'These seas are smooth as mirrors. Others said they saw some irregularities on the liquid surface, but were not sure whether they were caused by waves.
Rose Palermo, a geologist with the US Geological Survey and one of the researchers behind this study.
The scientific method meets imagination
To solve this cosmic puzzle, researchers did what they do best: they played with computers. I'll link the study here if you want to delve deeper into it then, and in the meantime I'll summarize it for you. The researchers created simulations of how Titan's coastlines might change under different conditions: with no erosion, with erosion caused by pounding waves, and with slow erosion caused by liquid methane “eating” shoreline material. Something like SimCity, but on a planetary scale.
After creating these virtual scenarios, the researchers compared them with Cassini's radar images. They chose four large Titanian lakes, including the Kraken Mare, which is as large as Earth's Caspian Sea. It was like trying to fit the pieces of a cosmic puzzle, where each piece was the size of a nation. Is the result?
Surprise: the winning wave of liquid methane
The scenario that came closest to reality was that of erosion caused by waves. It's as if Titan is inviting us to dive. Of course, it would be a slightly different bathroom from ours, with waves of liquid methane at -179°C, but who are we to judge other people's tastes?
Now that we know about the existence of waves, a question arises: what causes them? On Earth, winds create waves. On Titan? Well, it could be the same. Palermo and his colleagues now want to study these waves to better understand Titanian winds: how strong they are and where they blow. Pure poetry: trying to understand the weather by observing the ripples on a sea.
Obviously liquid methane.
