It's almost 1300-million kilometres from Earth, but scientists believe they have discovered evidence of water on one of Saturn's icy moons -- rekindling hope in the existence of life outside planet Earth.

The surprising discovery, made by the Cassini spacecraft, shows evidence of liquid water reservoirs that erupt from geysers (natural hot-springs) on Saturn's moon Enceladus.

That conclusion has scientists and astronomers in a giddy mood. They're so excited, in fact, that they're not ruling out the idea that this planet could sustain life.

"If you have liquid water and you have a heat source, then all you need are the ingredients, the basic raw materials of life, and you have a habitable environment," Discovery Channel's space expert Ivan Semeniuk told CTV.

"And what's astounding is, it's so far out of the part of the solar system where astronomers are used to thinking of life existing," Semeniuk said.

But patience is a virtue when it comes to space discovery. The next opportunity to look closely at this moon comes in 2008.

For now, scientists will have to make predictions based on the images they have now.

Images a 'smoking gun'

"High-resolution Cassini images show icy jets and towering plumes ejecting large quantities of particles at high speed," a NASA press release stated Thursday.

Carolyn Porco, Cassini's imaging team leader said Thursday that the discovery was a "smoking gun" that proved water existed on the planet.

"We realize that this is a radical conclusion -- that we may have evidence for liquid water within a body so small and so cold," Porco said.

"However, if we are right, we have significantly broadened the diversity of solar system environments where we might possibly have conditions suitable for living organisms."

Water reserves

Scientists examined reasons for the eruptions and concluded that it could be coming from liquid water reserves.

"The jets might be erupting from near-surface pockets of liquid water about 0 degrees Celsius," the report said.

NASA Scientist, Andy Ingersoll, told CTV that he would put "Enceladus up there with Mars and with one of Jupiter's moons, Europa, as one of the places we should look and examine carefully."

"One thing we're learning is that the habitable zone which we thought was a band around where the earth orbits is more like little isolated pockets way out there that our Habitable, perhaps," Ingersoll said.

While other moons in the solar system have liquid-water oceans buried kilometres below the surface, Saturn's reserve may only be meters below, Ingersoll said of the discovery.

Semeniuk added that this water, if it exists, would be "the most accessible water in the solar system apart from earth's own oceans -- it's just amazing."

Cassini scientist John Spencer said in a news release that scientists previously knew of, at most, three places where active volcanism exists: Jupiter's moon lo, Earth, and possibly Neptune's moon Triton.

He said, however, that "Cassini changed all that, making Enceladus the latest member of this very exclusive club, and one of the most exciting places in the solar system."

But David Morrision, a senior NASA scientist at the Astrobiology Institute, said people should not rush into believing that Saturn can support life because water is only one element of a number of factors that would be necessary for that to exist.

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

Enceladus was believed to be cold and still, but scientists now think that the moon has a south pole that is unusually warm.

The ambitious Cassini mission to Saturn is a joint partnership between NASA, the European Space Agency (ESA) and the Italian space Agency Agenzia Spaziale Italiana (ASI).

Launched from Cape Canaveral in 1997, the Cassini is a sophisticated $3.3 billion US robotic spacecraft that entered Saturn's orbit on July 1, 2004.

The spacecraft, run from Pasadena, California by NASA's Jet Propulsion Laboratory, is conducting a four year mission of detailed scientific observations in the Saturnian system.

The latest findings can be found in the new journal of Science.