Emily Chan
The icy shell of Titan, Saturn’s largest moon, may possibly contain a six-mile-thick layer of methane ice beneath its surface. The methane layer could make it easier to detect signs of life from Titan’s subsurface ocean.
Titan is a moon, but it is more similar to Earth than any other planetary body in the solar system. Aside from Earth, it is the only body that has an atmosphere and liquid lakes, rivers, and seas.
However, the frigid temperatures of Titan mean that the liquid is made up of hydrocarbons like methane and ethane. Still, Titan’s surface ice is composed of water.
A team of scientists at the University of Hawaii at Mānoa discovered that methane gas might be trapped within Titan’s icy shell, creating a crust up to six miles thick.
The gas could warm the ice shell and cause molecules to rise to Titan’s surface. Some of the molecules could indicate the presence of life. In addition, the warming may explain why Titan’s atmosphere is so rich in methane.
“If life exists in Titan’s ocean under the thick ice shell, any signs of life, biomarkers, would need to be transported up Titan’s ice shell to where we could more easily access or view them with future missions,” said Lauren Schurmeier, the lead researcher and scientist from the University of Hawaii. “This is more likely to occur if Titan’s ice shell is warm and connecting.”
The shallow impact craters on Titan were the first clue that led the researchers to deduce that a layer of methane ice may exist.
Only 90 impact craters have been seen on the surface of the moon. The scientists were confused by them because they should’ve been hundreds of feet deeper than what they were.
The team used computer modeling to determine why Titan’s impact craters were so shallow. They were able to test how much the surface of the moon would relax and rebound after it was struck by an asteroid if its icy shell was protected by a layer of methane clathrate.
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