And now water on Titan...

The Saturn moon Titan has just joined a growing band of solar system objects that may contain water. According to a paper published in the journal Science, radar images from the Cassini-Huygens mission reinforce predictions that a reservoir of liquid water exists beneath the satellite’s thick crust of ice. If confirmed, it would mean that Titan has two of the key components for life - water and organic molecules.

When the Cassini-Huygens mission began to observe Titan in 2004, the surface was thought to be completely covered with an ocean of hydrocarbons. But when the spacecraft turned its radar on the moon for the first time in 2004, and the Huygens probe parachuted to the surface a year later, a different picture emerged. Much of the surface was found to be solid, with geological features such as dunes, channels and impact craters, punctuated by vast "lakes".

Cassini's latest fly-by of Titan is providing a new glimpse of these features, which to researchers' surprise, are not in the place they should be. Coupled with models of how the moon spins, the data suggests that the observed seasonal variation in spin rate could only exist if a liquid ocean lay beneath the solid crust. The researchers, led by Dr Ralph Lorenz of Johns Hopkins University Applied Physics Laboratory, US, say their predictions can be checked in the proposed extended Cassini mission or in future missions.

Evidence suggests that Titan has two of the key constituents for the formation of life - water and organic molecules, and possibly a third - a source of energy, he said. Professor Zarnecki of the Open University said "We know there are organic molecules, the place is swarming in organics. Titan is 50% water-ice. If it is liquid, as this paper is implying some of it is, it looks as though we've got at least two of the things to initiate the chemistry that leads to life. It wouldn't be too far fetched to imagine certain spots on Titan where there would be a source of energy - maybe geothermal energy, as we have on Earth at the bottom of the oceans."

Past observations have shown that Titan in many ways resembles a very early Earth, particularly in the composition of its atmosphere. The major difference is the frigid temperatures out near Saturn.

I get the feeling that Titan will be the subject of further probes. It would be amazing if life was found there