New research suggests that Enceladus, a moon of Saturn, may be harboring a warm subsurface ocean. According to experts, that means the moon could be habitable.

Observations made by NASA's Cassini spacecraft, which has been investigating Saturn since 2004, reveal that one of the giant planet's moons may have hydrothermal activity underneath its icy surface. The evidence comes by way of rocky particles that may have recently formed, as a result of chemical reactions between hot water and rock.

Sean Hsu — a researcher at the University of Colorado Laboratory for Atmospheric and Space Physics, and lead author of the study — said for this kind of chemical reaction to happen, the water should be 190 degrees Fahrenheit or warmer.

"We report an analysis of silicon-rich, nanometre-sized dust particles (so-called stream particles) that stand out from the water-ice-dominated objects characteristic of Saturn," Hsu and his colleagues wrote for the March 11 issue of the scientific journal Nature.

"We interpret these grains as nanometre-sized SiO2(silica) particles, initially embedded in icy grains emitted from Enceladus' subsurface waters and released by sputter erosion in Saturn's E ring."

Hydrothermal activity happens when seawater reacts with rocky crust and then emerges as a warm, mineral-laden solution. It occurs naturally in oceans on Earth. Hsu's paper and another study, which was published in the Geophysical Research Letters, indicate that Enceladus may have similar active processes.

Researchers of the second study focused on the abundance of methane that is spewed into the icy moon's atmosphere. The methane could be produced by hydrothermal processes at the bottom of the moon's ocean, or it could be the result of the melting of a type of methane-rich ice that eventually gets to the surface.

In a statement, NASA said the evidence showing that Enceladus has signs of present-day hydrothermal activity resembling what is seen in Earth's deep oceans opens up unprecedented scientific possibilities.

NASA's Science Mission Directorate associate administrator John Grunsfeld said the findings could help with humanity's quest in finding out whether there are other life forms in the universe.

"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," Grunsfeld said.

"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."