New data on Saturn's moon, Titan, suggests it has a stiff "ice shell" with routes extending deep into the concealed ocean.

Researchers used data from NASA's Cassini spacecraft to break new ground on the topographic features of Saturn's famous moon, a University of California, Santa Cruz, press release reported.

The team noticed a "negative correlation between the gravity and topography signals on Titan."

"Normally, if you fly over a mountain, you expect to see an increase in gravity due to the extra mass of the mountain. On Titan, when you fly over a mountain the gravity gets lower. That's a very odd observation," study leader Francis Nimmo, a professor of Earth and planetary sciences at UC Santa Cruz, said.

The researchers believe the phenomenon can be explained by the presence of large chunks of ice below the surface.

"Because ice is lower density than water, you get less gravity when you have a big chunk of ice there than when you have water," Nimmo said.

In the researchers' model, they considered icebergs with massive roots that dwarf the bumps on the surface.

 "It's like a big beach ball under the ice sheet pushing up on it, and the only way to keep it submerged is if the ice sheet is strong," study leader Douglass Hemingway, a doctoral candidate in planetary geophysics at UCSC and lead author of the paper, said. "If large roots are the reason for the negative correlation, it means that Titan's ice shell must have a very thick rigid layer."

The team estimated the ice to be nearly 25 miles thick, with an impressive amount of erosion on the surface.

It would be almost impossible for volcanos to exist on a planet or moon with a thick shell. This finding sheds doubt on Titan-forming theories that claim volcanos were involved in the surface structure's composition.