The Irish Times - Monday, July 12, 2010

Discovery of water on Saturn moon raises prospect of life

In this section »

RONAN McGREEVY

THE SURPRISE discovery of water on one of Saturn’s moons holds out the tantalising prospect of life being elsewhere in the solar system, a lecture will hear tonight.

The Cassini mission which has been photographing Saturn, its rings and its moon system for six years was extended earlier this year by Nasa until 2017. It was supposed to end this year.

The probe, which was launched in 1997, has sent back stunning images of the ringed planet and its family of moons, but it has also made a number of noteworthy discoveries.

It found a methane atmosphere on Saturn’s biggest moon, Titan, along with lakes and rivers and a topography that looks a lot like Earth.

However, the biggest surprise was when plumes of water vapour were discovered erupting from the tiny moon Enceladus, which resembles a giant golf ball and where the surface temperature is nearly - 200 degrees.

It is thought that the moon has a massive internal heat source under its icy crust which is allowing liquid water to flow at great depths and possibly creating the conditions that would allow for life.

Dr Caitríona Jackman, a research associate on the mission, will give a lecture at Trinity College Dublin tonight hosted by Astronomy Ireland.

She is a native of Limerick and a graduate in applied physics from the University of Limerick. She has a doctorate in planetary science. She now works on the Cassini mission at Imperial College London.

She said Nasa’s decision to extend the mission was a vindication of the work of Cassini, which was still working well and now on its third extension.

“When we first flew past Enceladus we didn’t expect much and we were really surprised,” she said.

“We changed the orbit of the spacecraft and went back and had a closer look a few more times and now we are going to go back again.

“There is some thermal process similar to the geysers in Iceland that is taking place. The idea of having oceans of water so far away is one that captures the public imagination.

“If you have water and heat you have two of the possibilities for life. I wouldn’t bet my house on it, but it something that we need to look at in greater detail.”

Dr Jackman is not the only prominent Irish scientist working on the Cassini mission.

Prof Carl Murray is the head of the Cassini imaging team which has processed thousands of photographs from the mission over the last six years.