NASA scientists said that the liquid ocean hiding beneath the icy crust of Enceladus, the sixth largest moon of Saturn, covers the whole moon.

The discovery of the ocean, which was based on an analysis of seven years' worth of data gathered by the Cassini mission, holds implications that life could possibly evolve and might have already done so in this alien world, as NASA scientists say that the global ocean, which lies between the moon's core and the icy crust, could potentially harbor life.

An ocean covering the whole of Enceladus has crucial implications. While both regional sea with the capacity of Lake Vostok in Antarctica and global ocean could be hospitable to life under the right conditions, experts said that a global ocean is more likely capable of hosting life.

Astrobiologist Steven Vance, from NASA's Jet Propulsion Laboratory in Pasadena, said that a global ocean is far more compelling as it hints of the possibility that the ocean could support a diverse and dynamic ecology.

He added that the existence of a global ocean may indicate that the liquid reservoir has been there for a long time.

"If you want to know whether there might be complex life in some extraterrestrial ocean, you want to know if the ocean's been there for a long period of time," Vance said.

Cassini has uncovered potassium and sodium in the moon's geyser-like plumes. It has also found methane, water, oxygen and nitrogen as well as simple and complex organic molecules.

Researchers said that energy, organics and a salty ocean would make the presence of life in this extraterrestrial world plausible.

Sarah Ballard, from the University of Washington in Seattle, has identified criteria for a habitable moon. She said that for a moon to be capable of supporting life, it can't be too far away from its host planet as there is the risk of the moon venturing outside of the planet's magnetic shield, which provides protection from dangerous solar radiation.

A moon that is too close to its host planet would not be hospitable to life either because reflected light and radiation from the surface of the planet would make the conditions on the moon too hot.

Besides Enceladus, scientists also believe that Jupiter's moon Europa contains water. The U.S. space agency is already planning for a mission set to be launched in the 2020s to explore the giant lakes on the moon. Scientists hope that the mission will ultimately reveal if Europa is habitable or not.