Enceladus! Last November, special imaging sequences trained on Enceladus as it sat backlit by the sun revealed in striking detail the plume of material that we had flown through back in July as we buzzed the Enceladus surface. Many distinct narrow fountains of vapor and fine water ice particles, were clearly seen jetting from the south polar surface and reaching tens of miles into space. These jets supply material to an even larger diffuse plume that extends hundreds of miles above the south pole. A spectacular sight if there ever was one!
Our detailed analyses of these images have led us to a remarkable conclusion, documented in a paper to be published in the journal SCIENCE tomorrow, that the jets are erupting from pockets of liquid water, possibly as close to the surface as ten meters ... a surprising circumstance for a body so small and cold. Other Cassini instruments have found that the fractures on the surface and the plume itself contain simple organic materials, and that there is more heat on average emerging from the south polar terrain, per square meter, than from the Earth.
Gathering all the evidence and steeling ourselves for the "shockwave spread 'round the world", we find ourselves staring at the distinct possibility that we may have on Enceladus subterranean environments capable of supporting life. We may have just stumbled upon the Holy Grail of modern day planetary exploration. It doesn't get any more exciting than this.
A great deal more analysis and further exploration with Cassini must ensue before this implication becomes anything more than a suggestion. But at the moment, the prospects are staggering. Enceladus may have just taken center stage as the body in our solar system, outside the Earth, having the most easily accessible bodies of organic-rich water and, hence, significant biological potential.
Many years from now, it may well be that we and those who follow us will look back on these explorations of Saturn and take our discoveries on this otherwise cold little world to be the most wondrous of any we've ever made.
Future explorers of Saturn will have much to look forward to.
Carolyn Porco Cassini Imaging Team Leader CICLOPS/Space Science Institute Boulder, CO