Uncover the secret of methane lakes on Titan's moon

Little Mohamed Western

LONDON (Reuters) - Liquid methane lakes scattered on the surface of Titan (one of Saturn's moons) were formed when pockets of warm nitrogen exploded beneath the moon's surface, a new scientific study suggests.

Scientists say the idea will solve a mystery that emerged when NASA's Cassini probe was sent to explore Saturn and its aftershocks and recorded unprecedented data on the lakes.

The data recorded by Cassini during his mission, which ran between October 1997 and September 2018, showed a series of small lakes near the north pole of the moon, the edges of which rise hundreds of meters.

The discovery surprised scientists, because the erosion that formed other lakes on Titan could not be the reason for the formation of those slopes.

Nitrogen explosions
Scientists believed that most of Titan's lakes formed when liquid methane spilled into the moon's icy rocks to carve reservoirs - like the way water dissolved in limestone to form lakes on Earth - but the towering edges around these tiny lakes, tens of kilometers wide, were confusing to scientists. .

In contrast, the authors of the new scientific study, published in the journal Nature Geoscience on September 9, believe that the nitrogen explosions emitted from reservoirs under the surface of Titan that occurred during the warming period witnessed by Saturn in the past; Enough to create nozzles with high edges of debris later formed lakes that we now see.

The study, carried out by researchers from Cornell University and the Italian University of Annunzio, provides new evidence that millions of years ago Titan's freezing surface was extremely cold, with temperatures of about minus 180 degrees Celsius, allowing nitrogen in the liquid state.

Nitrogen cycle
Scientists already knew that Titan went through periods of cold and warming, where sunlight trapped methane in the atmosphere because of the heat, before it accumulates and then falls like rain during Saturn's "ice ages", seeping into the moon's crust forming puddles beneath the surface. This cycle is very similar to the water cycle on Earth.

But the new study suggests that as the concentration of methane, which now accounts for up to 5 percent of Titan's atmosphere, rises, the surface pockets of liquid nitrogen rise, turn into a high-explosive gas, and explosions that release nitrogen form craters on Titan's surface.

Unlike Earth, Titan is the only object in the solar system that has permanent liquids on its surface. It is ethane and liquid methane, not water.

The moon also contains carbon-rich organic compounds formed from interactions between methane and nitrogen, and the Cassini probe, which spent 13 years exploring Saturn and its aftershocks, uncovered an ocean of liquid water deep in Titan, which could provide a viable environment for a life form.

NASA is now planning a mission to study Titan's ocean and look for signs of life - past or present - using a nuclear-powered helicopter called Dragonfly, set to launch in 2026, that will reach the surface of Titan in 2034.