Hidden Ocean in Saturn's Moon? New Clues

New evidence for liquid water, 900,000,000 miles from the sun.

ByABC News
July 22, 2009, 11:14 AM

July 22, 2009 — -- In 2005, NASA's Cassini probe, orbiting Saturn, made a tantalizing discovery: Enceladus, one of Saturn's moons, was venting something -- possibly liquid water -- into the airless space around it.

In the frozen wastes around Saturn, this was (please forgive the pun) really cool. How could there be water nearly 900 million miles from the sun? That's almost 10 times as far out as Earth is.

Enceladus. Even the name, coming from Greek mythology, rolls off the tongue mysteriously. En-CELL-a-dus.

It is a small world, 300 miles in diameter, covered in a thick layer of ice. It whips around Saturn in 1.4 days, meaning the gravitational pull of the great ringed planet on the little moon's innards must be fierce.

Saturn has more than 60 known moons; Enceladus is the sixth largest. The venting appears to come from fractures or fissures in the ice near its south pole.

But liquid water? You can find water in the form of vapor or ice all over the universe (think of comets, with their frozen cores and filmy tails), but liquid water is the stuff of life as we know it, and when NASA made its original announcement four years ago, it set minds racing. There were many doubters.

Now, a team of scientists has analyzed the chemical makeup of one of the plumes, and found some intriguing clues that support the liquid-water theory. Their report is in Thursday's edition of the journal Nature.

They found ammonia, argon, various organic compounds and salts, some of which could act as a kind of celestial antifreeze, keeping the waters of Enceladus from freezing.