Observations from the Cassini spacecraft currently studying Saturn and its myriad moons shows Enceladus, one of the brightest objects in the Solar System, to be a geologist's dream, with an active plume spewing water and other material spaceward, as well as a hot spot of thermal activity at its south pole.
Enceladus' active nature points toward subsurface water reservoirs beneath its icy exterior, much like that believed to churn just under the surface of Jupiter's moon Europa, researchers said. But unlike Europa, which researchers believe harbors a vast ocean beneath kilometers of thick ice, Enceladus' water may be just below the surface.
"You've got liquid water, and it's liquid water interfacing with rock... and there's energy," NASA Cassini scientist Candice Hansen-Koharcheck told SPACE.com. "We've got the very most basic ingredients here, and so that notches it up on the biological potential list."
"Any life that existed could not be luxuriant and would have to deal with low temperatures, feeble metabolic energy, and perhaps a severe chemical environment," Kargel wrote. "Nevertheless, we cannot discount the possibility that Enceladus may be life's distant outpost."
This sounds like pretty huge news to me: Enceladus has an atmosphere and liquid water -- not just ice -- and I think that makes it the first such place besides Earth where that environment is known to exist. That makes it more hospitable to life than Mars (unless you mean "Mars as of three billion years ago") and possibly more hospitable than Antarctica... The fact that the water is in a geologically active environment is also important, because odds are that you need not just water but a chaotic and mineral-rich environment to get life to kick-start itself.