Enceladus: Complex Organic Molecules Found on Saturn's Moon, Boost Hopes of Finding Alien Life

Saturn's sixth largest moon, Enceladus, is gradually gaining a reputation as the most promising place in the solar system to search for alien life.

The brilliant white world has a global ocean of salty, liquid water below its frozen surface that has existed for billions of years—more than enough time for life to emerge. Furthermore, it is rich in hydrothermal activity and organic molecules that may provide the warmth and nutrients needed for organisms, as we understand them, to evolve.

Now, an international team of scientists has made a discovery that boosts the chances that life could exist there.

In a paper published in the journal Nature, the researchers describe how they found large, complex, carbon-rich organic molecules—the building blocks of life—in plumes of material emerging from cracks in the moon's icy surface.

Previously, scientists had only identified very simple organic molecules, which contained only a few carbon atoms, in Enceladus's plumes.

"We found large molecular fragments from the subsurface ocean of Enceladus that show structures typical for very complex organic molecules," Nozair Khawaja, a planetary scientist from Heidelberg University and author of the study, told Newsweek.

"These huge molecules contain a complex network often built from hundreds of atoms of carbon, hydrogen, oxygen and likely nitrogen that form ring-shaped and chain-like substructures. This is the first ever detection of such a large and complex organic molecules from extraterrestrial water."

According to, Christopher Glein, another author of the study from the Southwest Research Institute (SwRI) in San Antonio, Texas, the discovery creates "incredible excitement" that Enceladus would be an "excellent place" for microbial life to live.

"Liquid water, a source of energy, and [complex] organic molecules are required to support life as we know it," he told Newsweek. "We now know that Enceladus' ocean has all of these ingredients, today. Besides Earth, no other place in the solar system has confirmed evidence of all three requirements in a contemporary environment that can support life."

The scientists made their findings using data collected by NASA's Cassini spacecraft during a flyby of the moon on October 28, 2015, before the end of its mission.

Saturn’s rings cast shadows on the planet’s cloud tops, providing a perfect backdrop for the brilliant sphere of Saturn’s moon Enceladus. The tiny world’s bright white surface results in part from a snow of material originating from the towering plume of icy particles at Enceladus’s south pole. NASA/JPL-Caltech/Space Science Institute

Researchers had previously discovered that these plumes contained molecular hydrogen, which is thought to originate from chemical interactions between warm water in the moon's subsurface oceans and its rocky core. On Earth, hydrogen provides a source of chemical energy that supports microbes that live in the oceans near hydrothermal vents.

The new findings have important implications for future space exploration missions, according to Glein.

"A future spacecraft could fly through the plume of Enceladus, and analyze those complex organic molecules using a high-resolution mass spectrometer to help us determine how they were made," he said in a statement. "We must be cautious, but it is exciting to ponder that this finding indicates that the biological synthesis of organic molecules on Enceladus is possible."