Researchers Propose Mission To Find Extraterrestrial Life On Saturn's Icy Moon Enceladus

A team of researchers led by the University of Arizona believe Saturn's moon Enceladus is a prime candidate for potentially harboring alien life. The team thinks that a future mission to Enceladus could provide answers without even landing on the icy surface.

NASA's Cassini spacecraft concluded its historic 13-year mission of exploring Saturn and its moons by plunging into the atmosphere of the gigantic planet. Thomas Zurbuchen, Associate Administrator for NASA's Science Mission Directorate at NASA's Headquarters in Washington stated that "Cassini's discovery of ocean worlds at Titan and Enceladus changed everything, shaking our views to the core about surprising places to search for potential life beyond Earth." Now, a team of researchers want to send another spacecraft back to Enceladus to delve deeper into the possibility of finding alien life.

Researchers believe that the mystery of whether microbial alien life inhabits Enceladus, one of Saturn's 83 moons, could be solved by an orbiting space probe, according to a new study led by the University of Arizona. NASA first surveyed Enceladus in 1980 with Voyager 1, but that flyby did not give much insight into the "snowball" in the sky. It was not until NASA's Cassini probe provided greater detail that scientists began to see the incredible potential of the icy rock. Scientists discovered that its "thick layers of ice hides vast, warm saltwater ocean outgassing methane, a gas that typically originates from microbial life on Earth."

The methane, along with other indicators of molecular life, were detected as Cassini passed through giant water plumes that were erupting from the surface of Enceladus. The plumes originate from being "squeezed and tugged" by Saturn's enormous gravitational field. Using this information, a team of scientists calculated that if life could have emerged on Enceladus, that it could explain why the icy moon is "burping up methane."

"To know if that is the case, we must go back to Enceladus and look," remarked Regis Ferriere, senior author of the new paper and Associate Professor in the University of Arizona Department of Ecology and Evolutionary Biology.

The excess methane Cassini detected in the plumes of Enceladus makes researchers think of the ecosystems found in the depths of Earth's oceans: hydrothermal vents. These vents spew extremely hot, mineral-saturated seawater. Due to the organisms' lack of sunlight, they must find energy in chemical compounds released by the vents in order to survive.

"On our planet, hydrothermal vents teem with life, big and small, in spite of darkness and insane pressure," Ferriere explained. "The simplest living creatures there are microbes called methogens that power themselves even in the absence of sunlight."

Antonin Affholder, a postdoctoral research associate at the University of Arizona added, " Enceladus' biosphere may be very sparse. And yet our models indicate that it would be productive enough to feed the plumes with just enough organic molecules or cells to be picked up by instruments onboard a future spacecraft."

Ferriere explained that due to the possibility of life on Enceladus being very sparse, there is still a good chance that a spacecraft would not find enough organic molecules in the plumes to definitively conclude that life exists there.

Affholder concluded by stating, "The definitive evidence of living cells caught on an alien world may remain elusive for generations. Until then, the fact that we can't rule out life's existence on Enceladus is probably the best we can do."