Cassini Probe Finds Ocean Below Icy Surface of Saturn’s Moon Titan

According to some recent information released by NASA, the Cassini spacecraft, currently on its mission exploring Saturn and its moons, has sent back data which appears to indicate that one of Saturn’s larger moons, Titan may have a liquid ocean below its icy surface.

The conclusion is based on the amount of stretching and squeezing of Titan’s surface which occurs as it orbits Saturn. This is much the same as how the tides of the Earth rise and fall due to the orbit of our moon. The NASA scientists surmised that if Titan had only a solid surface, it would only bulge about 3 feet. Instead what Cassini showed them was a bulge of about 30 feet.

“Cassini’s detection of large tides on Titan leads to the almost inescapable conclusion that there is a hidden ocean at depth,” said Luciano Iess, lead author of a paper on the findings published in the journal Science last week, and a Cassini team member at the Sapienza University of Rome, Italy. “The search for water is an important goal in solar system exploration, and now we’ve spotted another place where it is abundant.”

The data was gathered during six close passes of Titan by Cassini during the period from from Feb. 27, 2006, to Feb. 18, 2011. The information was then relayed to researchers on the ground here on earth via NASA’s Deep Space Network (DSN).

“We were making ultrasensitive measurements, and thankfully Cassini and the DSN were able to maintain a very stable link,” said Sami Asmar, a Cassini team member at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “The tides on Titan pulled up by Saturn aren’t huge compared to the pull the biggest planet, Jupiter, has on some of its moons. But, short of being able to drill on Titan’s surface, the gravity measurements provide the best data we have of Titan’s internal structure.”

While the data does not give a good indication of the exact depth of Titan’s sub-surface ocean, the scientists feel relatively confident that it is water. The assumption is based on the fact that Titan’s surface is mostly made of water ice, and water in solid form has been found in abundance in the moons of the planets in the outer solar system.

Perhaps most interesting to the scientists about this recent discovery of water on Titan is the implications it has about the mystery of methane replenishment on Titan. “The presence of a liquid water layer in Titan is important because we want to understand how methane is stored in Titan’s interior and how it may outgas to the surface,” said Jonathan Lunine, a Cassini team member at Cornell University. “This is important because everything that is unique about Titan derives from the presence of abundant methane, yet the methane in the atmosphere is unstable and will be destroyed on geologically short timescales.”