The Saturn-orbiting probe Cassini has given scientists clues on the depths of Kraken Mare, the largest sea on Saturn's biggest moon, Titan. Kraken Mare is near Titan's north pole and spans 154,000 square miles or about five times the size of Lake Superior in North America.

The probe's radar measurements along a 25-mile long stretch at the eastern shore of the Kraken Mare have revealed that the hydrocarbon sea is between 66 to 115 feet deep, but since Cassini only managed to explore a small area of the sea, scientists believe that the body of water is much deeper.

Cassini gathered the data during a flyby in August when it used its radar instruments to collect altimetry data along a 120-mile track of the extraterrestrial sea. For the 25-mile region near the mouth of a large flooded water, the radar beam bounced back to Cassini from the bottom of the sea unraveling a depth of up to 115 feet.

Plots of radar echoes shared by National Aeronautics and Space Administration's (NASA) Jet Propulsion Laboratory (JPL) indicate the sea's varying depths.

"The altimetry echoes show the characteristic double-peaked returns of a bottom-reflection," the agency reported. "The tallest peak represents the sea surface; the shorter of the pair represents the sea bottom. The distance between the two peaks is a measure of the liquid's depth."

The Cassini spacecraft, however, did not receive radar echo from the sea floor in some areas and scientists attribute this to the possibility that this part of the sea may be too deep to be penetrated by the radar beam. It is also possible that the signal had been absorbed by the liquid, which is composed of methane and ethane.

"Scientists think that, for the areas in which Cassini did not observe a radar echo from the seafloor, Kraken Mare might be too deep for the radar beam to penetrate," NASA officials said.

The altimetry data for the region in and around the sea showing steep slopes that lead to Kraken Mare also indicate that the sea is indeed possibly deep.

Cassini's new findings will be presented by Alexander Hayes, planetary scientist from the Cornell University, at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society (AAS) in Arizona this week.

The Cassini-Huygens mission is collaborative project of the European Space Agency (ESA), NASA and Italy's space agency Agenzia Spaziale Italiana (ASI).