Saturn’s Moon Titan May Not Have an Underground Ocean After All

A new analysis of data from NASA’s Cassini spacecraft may upend Titan’s status as an ocean world. But it might still have pockets of water within a slushy ice layer

Sara Hashemi | Daily Correspondent

December 19, 2025

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Around 20 years ago, the Cassini-Huygens mission—a joint endeavor by NASA, the European Space Agency and the Italian Space Agency—provided some mind-blowing observations. Data from the spacecraft orbiting Saturn hinted that an ocean might lurk beneath the surface of the planet’s largest moon, Titan. That meant the lunar companion could potentially host life.

But a new analysis of Cassini’s observations suggests that those early assumptions about Titan may have been wrong. Instead of a vast ocean of water, Titan may harbor an icy interior with layers of slush and pockets of warm water. The work was published in the journal Nature and presented at the American Geophysical Union’s annual meeting on December 17.

Cassini studied Saturn and its moons from 2004 to 2017, making more than 100 flybys past Titan. The moon’s surface seemed to stretch and squish during its elliptical orbit in response to the planet’s gravity. So, in 2008, researchers reported that a global underground ocean probably allowed Titan’s exterior to move so much.

“The deformation we detected during the initial analysis of the Cassini mission data could have been compatible with a global ocean,” Baptiste Journaux, a co-author of the new study and a planetary scientist at the University of Washington, says in a statement. “But now we know that isn’t the full story.”

In the new research, Journaux and his colleagues used improved techniques to reanalyze Cassini’s data. Then, they simulated Titan’s movements and deformation as it whips around Saturn. The moon’s surface stretched roughly 15 hours after passing the planet’s peak gravitational pull, the team found, suggesting a syrupy substance—rather than a runny one—sits beneath Titan’s exterior.

Based on their findings and past data, the researchers propose that Titan has an icy outer shell about 100 miles deep covering a roughly 230-mile-thick layer of icy slush.

“This is the first time that everything is explained at once by a single model,” Flavio Petricca, a study co-author and planetary scientist at NASA’s Jet Propulsion Laboratory, tells Hannah Richter at Science. “That’s the most compelling evidence that we have.”

Even if Titan contains a slushy interior, it could still host life. The researchers’ analysis suggests that the layer contains pockets of water that could reach 68 degrees Fahrenheit. Nutrients may gather there, which would be more conducive to the development of microbial life than if they were diluted across an ocean. “I think that this [patchy] configuration might be even more interesting than a global ocean,” Petricca says to Science.

But not everyone is convinced by the new findings. 

While “certainly intriguing and will stimulate renewed discussion ... at present, the available evidence looks certainly not sufficient to exclude Titan from the family of ocean worlds,” Luciano Iess, a planetary scientist at the Sapienza University of Rome whose previous Cassini work hinted at an ocean on Titan, writes in an email to Marcia Dunn at the Associated Press.

NASA’s upcoming Dragonfly mission could provide some of that evidence. The spacecraft is planned to launch in 2028 and should reach Titan around six years later. It will spend roughly three years sampling the surface to investigate the moon’s potential for spawning life.

Until then, researchers can always discover more by revisiting past observations.

“We need to keep examining existing spacecraft data,” says Jani Radebaugh, a planetary scientist at Brigham Young University who was not involved in the new research, to Meghan Bartels at Scientific American. “There is always going to be something new that we can find out if we look carefully.”

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Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.