Is there life out there?

THE Cassini spacecraft has found evidence of liquid water spewing from geysers on one of Saturn's icy moons, raising the tantalising possibility the celestial object harbours life.

The surprising discovery excited scientists, who say Saturn moon, Enceladus, should be added to the shortlist of places within the solar system most likely to have extraterrestrial life.

Recent high-resolution images snapped by the orbiting Cassini confirmed the eruption of icy jets and giant water vapour plumes from geysers resembling frozen Old Faithfuls at Enceladus' south pole.

"We have the smoking gun" that proves the existence of water, said Carolyn Porco, a scientist from the Space Science Institute in Colorado.

If Enceladus does harbour life, it probably consists of microbes or other primitive organisms capable of living in extreme conditions, scientists say. The findings were published in the journal Science.

David Morrison, a senior NASA scientist, cautioned against rushing to judgment about whether the tiny moon could support life. Scientists generally agree habitats need several ingredients for life, including water, a heat source and the right chemical recipe.

"It's certainly interesting, but I don't see how much more you can say beyond that," Mr Morrison said.

Scientists believe Mars and Jupiter's icy moons might have - or once had - conditions hospitable to life.

Saturn is around 800 million miles from Earth. Enceladus, 314 miles across, is the shiniest object in the solar system.

The water is believed to vent from fissures in the south pole. Ms Porco said the venting has probably been going on for thousands of years, potentially providing a lasting heat source.

The Cassini-Huygens mission is a joint NASA-European Space Agency project launched in 1997 and went into orbit around Saturn in 2004.