A hidden habitat on ENCELADUS
A haven for life could exist on the subsurface sea's floor
Saturn’s icy moon Enceladus could be primed for life. Hints that there may be hydrothermal vents on the floor of the subsurface ocean, around which life could be thriving, were found by NASA’s Cassini spacecraft in October 2015 when it dove through the giant water plumes that erupt from the moon’s surface. The moon contains the right chemical mixture of water and elements necessary to create life, but until now there has been no known source of the energy needed to kick-start the process.
“Hydrogen is a source of chemical energy for microbes that live in the Earth’s oceans near hydrothermal vents,” says Hunter Waite, principal investigator for Cassini’s Ion Neutral Mass Spectrometer (INMS). “Our results indicate that the same chemical energy source is present in the ocean of Enceladus.”
The probe’s INMS instrument found traces of molecular hydrogen within the water plumes. On Earth, the element is found near deep sea vents that provide both the heat and minerals necessary to create life, and are often teeming with microbes.
“We have not found evidence of the presence of microbial life in the ocean of Enceladus, but the discovery of hydrogen gas and the evidence for ongoing hydrothermal activity offer a tantalising suggestion that habitable conditions could exist beneath the moon’s icy crust,” said Waite.
Cassini will be unable to study the moon further as the discovery comes less than six months before the end of the 12-year mission. However, the find could mean similar vents exist on Jupiter’s moon Europa, which will be visited by both ESA’s Jupiter Icy Moon Explorer (JUICE) and NASA’s Europa Clipper in the next decade. See Comment, right