According to new findings published in the August 29 issue of Nature, Saturn’s largest moon Titan seems to take the meaning of “cold as ice” to a whole new level. Scientists at the University of California in Santa Cruz have found that the moon’s icy outer shell is far thicker and more rigid than previously believed, and while that does not bode well for signs of life, it does indicate a very strange interior.

Past research suggested that an ocean lies about 30-120 miles beneath Titan’s icy crust, and researchers want to explore this underground ocean under the premise that where there is water, there may be life. Planetary scientists Douglas Hemingway and Francis Nimmo at the University of California, Santa Cruz, analyzed the Cassini probe’s scans of Titan’s gravity field and then compared these gravity results with the structure of Titan’s surface. The amount of mass in the interior of a celestial body determines the strength of the gravitational pull on its surface. More mass equals a stronger pull.

With this general knowledge, the team expected that the areas of the strongest gravitational pull would be in the regions of high elevation, and weakest gravitational pull would be found in regions of low elevation. Titan is a moon full of surprises, apparently, for the team found that the regions of high elevation actually had the weakest gravitational pull.

“We assumed at first that we got things wrong, that we were seeing the data backwards,” said Hemingway, a doctoral candidate in planetary geophysics at UCSC and lead author of the paper, “but after we ran out of options to make that finding go away, we came up with a model that explains these observations.”

The model helped the team come to a conclusion regarding the anomaly, where the mountains essentially have roots. “It’s like how most of an iceberg actually lies submerged underwater,” Hemingway said. “If that root is really big, bigger than normal, it would displace water underneath it.” Ice is less dense than water, and the roots on Titan are big enough to displace the water around them, which in turn weakens the region’s gravitational pull.

“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,” said Hemingway, “If large roots are the reason for the negative correlation, it means that Titan’s ice shell must have a very thick rigid layer.”