Article Posted on : - May 04, 2011

This artist's illustration shows the likely slushy interior structure of Saturn's moon Titan deduced from gravity field data collected by NASA's Cassini spacecraft. Photo: NASA

WASHINGTON (BNS): NASA spacecraft Cassini has added extra evidence on the presence of liquid water beneath the frigid surface of Saturn's moon Titan.

The observations were made by NASA's Cassini probe, which has been eyeing Saturn and its rings and moons from orbit since arriving at the gas giant in 2004.

According to the researchers, certain details of Titan's orbit and rotation aren't compatible with the behaviour of a celestial body that is completely solid all the way through. But these details make a lot of sense if the huge moon is assumed to have a subsurface ocean, likely of liquid water.

Titan, the largest of Saturn's more than 60 known moons, is considered one of the leading candidates to host life beyond Earth.

While its surface temperatures hover around a frosty minus 290 degrees Fahrenheit (minus 179 degrees Celsius), Titan boasts a thick, nitrogen-rich atmosphere in which thousands of different types of organic molecules swirl about. The moon also has a weather cycle based on methane, with methane rain pooling in liquid hydrocarbon lakes.

Current thinking about Titan's formation and evolution suggests that this ocean would be composed primarily of water -- perhaps with a dash of ammonia -- rather than hydrocarbons or some other substance, Space.com quoted study lead author Rose-Marie Baland as saying.

Once the existence of water is proved, Titan would join several other frigid moons in the outer solar system -- such as Saturn's moon Enceladus and Jupiter's Europa -- in the water-ocean club.