Water on Saturn moon

Images captured by Cassini in February show plumes of icy particles extending above the south polar region of Saturn’s moon Enceladus. (AP)

New Delhi, March 10: Saturn’s moon Enceladus may hold underground reservoirs of liquid water that erupts from its surface as geysers, scientists announced today, triggering speculations about living organisms in a cold, hostile habitat.

Images sent by the Cassini spacecraft, which has been orbiting Saturn and its moons for the past 20 months, have revealed narrow jets of water and icy particles erupting from the south polar region of Enceladus, Cassini team members said.

In research papers published today in the US journal Science, they said images captured during Cassini’s close approaches to Enceladus show the moon’s south pole terrain spewing jets of water vapour and fine icy particles. The abundance and the speed of the particles suggest these jets are erupting from underground pockets of liquid water above 0 degrees Celsius.

The scientists said evidence of liquid water close to the surface of a small moon is a radical finding. “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,” said Carolyn Porco, the Cassini imaging team leader at the Space Science Institute in Boulder, Colorado.

“It doesn’t get any more exciting than this.”

The south pole terrain of Enceladus is littered with boulders of ice the size of houses, and the ground is cracked with ridges and complex fracture patterns that are indicative of geological activity. It appears to be a ‘hot spot’ on an icy moon.

While the average surface temperature on Enceladus is around minus 200 degrees Celsius, instruments on Cassini showed that the south pole region is relatively warm ? with temperatures between minus 125 degrees to minus 160 degrees Celsius.

The possibility of liquid water on Enceladus has triggered speculations about life on the Saturnian moon. “Any life (there) would have to deal with low temperatures... and a severe chemical environment,” Jeffrey Kargel from the University of Arizona said in a commentary published in the same issue of Science.

But, Kargel wrote, “we cannot discount the possibility that Enceladus might be life’s distant outpost”.

In the near-vacuum atmosphere on the moon’s surface, liquid water would boil away into space, erupting and carrying particles of ice and water with the vapour. Analysis of the jets shows that most of the particles eventually fall back to the surface, the Space Science Institute said.

The source of the underground warmth in the region’s ‘hot spot’ and the geological activity there is still unknown.