Titan, Saturn’s moon, may not harbor an ocean under its icy surface as previously believed

Data from NASA’s Cassini mission, which began in 1997 and lasted almost 20 years, made researchers suspect the possibility that Titan harbored a large mass of liquid water under its ice layer, but when they modeled the moon with the ocean, the results did not coincide with the physical properties of these ecosystems.

“Instead of an open ocean, like we have on Earth, We are probably looking at something more similar to Arctic sea ice or aquifers.which would have implications for the type of life we ​​could find,” says Baptiste Journaux, a space researcher at the American University of Washington.

Journaux is one of the authors of the article published in Nature this Wednesday, revealing the latest conclusions about Titan.

The Cassini mission produced a wealth of data about Saturn and its 274 moons. Titan, shrouded in a hazy atmosphere, is the only world other than Earth known to have liquid on its surface. Its temperature would be around -182 degrees Celsius, so it would be a frozen surface.

As Titan orbited Saturn elliptically, researchers observed that the moon stretched and flattened depending on its position relative to the planet, so in 2008, They proposed that the moon must have a huge ocean beneath the surface to allow such significant deformation.

“The degree of deformation depends on Titan’s interior structure. A deep ocean would allow the crust to flex more under Saturn’s gravitational pull. If Titan were completely frozen, it would not deform as much,” says Journaux.

“The deformation we detected during the initial analysis of the Cassini mission data could have been compatible with a large subsurface ocean. We now know that is not entirely the case,” he adds.

Time is the key

In the new study, the researchers introduce a new level of subtlety: time. Titan’s shape change lags about 15 hours behind the peak of Saturn’s gravitational pull. Like a spoon stirring honey, it would take more energy to move a thick, viscous substance than it would to move liquid water.

Measuring that delay revealed to scientists how much energy is needed to change Titan’s shape, which led them to conclude that its interior is viscous, not liquid.. “It was irrefutable proof that indicated that the interior of Titan is different from what was deduced from previous analyses,” says another of the authors, Flavio Petricca, a NASA researcher.

The new model they propose for Titan presents more sleet and considerably less liquid water than the previous one, as the sleet is thick enough to explain the delaybut still contains water, allowing Titan to transform when pulled.

Petricca reached this conclusion by measuring the frequency of radio waves coming from the Cassini spacecraft during flybys of Titan, and Journaux helped support the results with thermodynamics studies.

The possibility of finding life remains open

Although the idea of ​​an ocean on Titan spurred the search for life there, Researchers believe the new findings could improve the chances of finding it.

Analysis indicates that pockets of fresh water on Titan could reach 20 degrees. Any available nutrients would be more concentrated in a small volume of water, compared to an open ocean, which could facilitate the growth of simple organisms.

Although researchers are unlikely to discover fish in slush channels of these lakes, If life is found on Titan, it could resemble Earth’s polar ecosystems.

Journaux is part of the team on NASA’s upcoming Dragonfly mission to Titan, scheduled to launch in 2028. The data collected here will guide the mission, and Journaux hopes to return with some proof of life on the planet and a definitive answer about the ocean.