Saturn’s moon Enceladus contains complex organic molecules, according to scientists from the European Space Agency. Previous work detected only simple compounds. Frank Postberg, the lead researcher on the project, said in a statement, “This is the first evidence of large organic molecules from an extraterrestrial aquatic world. They can be generated only by equally complex chemical processes.”
The study, published this week in the peer-reviewed journal Nature, was based on data from the Cassini-Huygens mission, a joint initiative of NASA, the ESA, and Italy’s ASI space agency. Cassini was launched in 1997 and spent 13 years circling Saturn and its moons. The spacecraft carried two mass spectrometers called the Cosmic Dust Analyzer (CDA) and the Ion and Neutral Mass Spectrometer (INMS) that examined the ejected ice grains coming from the moon’s plume and Saturn’s E ring. Cassini plunged into Saturn’s atmosphere and ended its mission on Sept. 15, 2017.
This is not the first time Cassini has detected organic molecules on Enceladus, but the newly discovered ones are significantly larger than previous discoveries. The new molecules made up of hundreds of atoms of carbon, hydrogen, oxygen and nitrogen arranged in rings and long chains with masses above 200 atomic mass units. The previously known compounds contained one or two carbon atoms and a few atoms of hydrogen with masses of about 50 atomic mass units.
The researchers think these organic compounds originate in Enceladus’ core and then flow into the subsurface ocean via hydrothermal vents. That makes life on Enceladus a possibility. Life is possible when the complex molecules are combined with liquid water and hydrothermal activity. Christopher Glein, a co-author of the study and geochemist at the Southwest Research Institute in San Antonio, Texas, commented in an email, “Besides Earth, no other place in the solar system has confirmed evidence of all three requirements in a contemporary environment that can support life.”
Enceladus, the sixth-largest of Saturn’s 62 confirmed moons, has been previously mentioned as a possible host for supporting life due to the presence of hydrogen in its atmosphere. Researchers now want to send a space probe to explore the icy moon up close.