It's often suspected that life on earth may've begun in the hydrothermal vents resting deep on the ocean floor. Even though it's far from sunlight it's thought that bacterial life may've thrived there on a diet of hydrogen, carbon dioxide, and sulfur.
Now, NASA's Cassini spacecraft has provided some evidence that Saturn's moon Enceladus shows signs of hydrothermal activity, and thus possibly a warm ocean, which could be similar to that found on the deep seabeds of earth.
"These findings add to the possibility that Enceladus, which contains a subsurface ocean and displays remarkable geologic activity, could contain environments suitable for living organisms," says John Grunsfeld, astronaut and associate administrator of NASA's Science Mission Directorate in Washington. "The locations in our solar system where extreme environments occur in which life might exist may bring us closer to answering the question: are we alone in the universe."
Hydrothermal activity occurs when seawater infiltrates and reacts with a rocky crust and emerges as a heated, mineral-laden solution, a natural occurrence in Earth's oceans. According to two science papers, the results are the first clear indications an icy moon may have similar ongoing active processes.
The first paper, published this week in the journal Nature, relates to microscopic grains of rock detected by Cassini in the Saturn system. An extensive, four-year analysis of data from the spacecraft, computer simulations and laboratory experiments led researchers to the conclusion the tiny grains most likely form when hot water containing dissolved minerals from the moon's rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius).
"It's very exciting that we can use these tiny grains of rock, spewed into space by geysers, to tell us about conditions on—and beneath—the ocean floor of an icy moon," said the paper's lead author Sean Hsu, a postdoctoral researcher at the University of Colorado at Boulder.
Lots to do yet before they confirm these are actually hydrothermal vents like those found on earth, even yet discover signs of life, but it's exciting nonetheless—and could prove that Enceladus is yet another target in our solar system to search for alien lifeforms.