Titan's Lakes formed by explosions of methane beneath the surface

Except the Earth, there is only one body in our solar system that has a liquid on the surface: Titan, one of Saturn's moons. But the liquid on Titan is not water, it's methane and ethane. As Titan is so cold, the methane and ethane that would produce gases on Earth are cooled in liquid form and rain on the Moon in a pattern similar to that of our water cycle.

Because of this precipitation, Titan has methane lakes on its surface. But there is something strange about these lakes. Scientists have noticed that some of the lakes have steep slopes up to several meters high. Now, using the data from the Cassini probe, they think they know why: the rims are caused by nitrogen explosions from the underground depths.

Previously, it was thought that lakes on Titan formed similarly to a type of lake on Earth called karst lake. It is here that the liquid falls to the surface and dissolves it gradually, penetrating into the bedrock and forming a hollow. But now, astronomers have found that some of Titan's lakes are forming differently. As the crust of the moon warmed, pockets of liquid nitrogen beneath the surface warmed up to turn into gas and explode outward, forming craters on the surface. This explains the high ridges of some lakes.

"The rim is rising and the karst process is working in the opposite direction," said Giuseppe Mitri of the Italian University of Annunzio, head of the research team, in a statement. "We have not found any explanation that corresponds to a karstic lake basin. In reality, the morphology was more compatible with an explosion crater, where the rim is formed by material ejected from inside the crater. It's a totally different process.

The results give clues to the evolution of the moon's atmosphere over time. "These lakes with steep edges, ramparts and raised edges would mark the times in Titan's history during which liquid nitrogen was on the surface and in the crust," Mitri said.

Although the Cassini mission ended in 2017, the probe data is still being used to make new scientific discoveries. "This is a completely different explanation of the steep slopes around these small lakes, which is a huge puzzle," said Linda Spilker, Cassini project scientist, in the same statement. "As scientists continue to exploit the Cassini data treasure, we will continue to assemble more and more pieces of the puzzle. Over the next few decades, we will understand better and better the system of Saturn. "

Editor's recommendations