Complex organic molecules found on Enceladus
Scientists have found that large, carbon-rich organic molecules are ejected from cracks in the icy surface of Saturn’s moon Enceladus. They did this by using mass spectrometry data from NASA’s Cassini spacecraft.
Southwest Research Institute scientists think chemical reactions between the moon’s rocky core and warm water from its subsurface ocean are linked to these complex molecules, as per the report on Nature.
Prior to its deorbit in September of 2017, Cassini sampled the plume of material emerging from the subsurface of Enceladus. The Cosmic Dust Analyzer (CDA) and the SwRIled Ion and Neutral Mass Spectrometer (INMS) made measurements, both within the plume and Saturn’s E-ring, which is formed by plume ice grains escaping Enceladus’ gravity.
“Even after its end, the Cassini spacecraft continues to teach us about the potential of Enceladus to advance the field of astrobiology in an ocean world,” Dr. Glein, SwRI’s space scientist said.
During Cassini’s close flyby of Enceladus on Oct. 28, 2015, INMS detected molecular hydrogen as the spacecraft flew through the plume. Previous flybys provided evidence for a global subsurface ocean residing above a rocky core. Molecular hydrogen in the plume is thought to form by the geochemical interaction between water and rocks in hydrothermal environments.
“Hydrogen provides a source of chemical energy supporting microbes that live in the Earth’s oceans near hydrothermal vents,” said SwRI’s Dr. Hunter Waite, INMS principal investigator. “Once you have identified a potential food source for microbes, the next question to ask is ‘what is the nature of the complex organics in the ocean?’ This paper represents the first step in that understanding—complexity in the organic chemistry beyond our expectations!”