May 53 min read

Frozen Worlds: Detecting Life in a Single Ice Grain

Fairfax, VA

Does life beyond our planet exist? Such a question has been the subject of consideration for as long as we can remember, leading to intensive efforts to answer this question. According to a recent paper from researchers from University of Washington and the Freie Universität Berlin, we may be able to identify the presence of such life in our very own solar system, more specifically, on the moons of Jupiter and Saturn. 2017’s Cassini mission, a space research venture by NASA, the European Space Agency, and the Italian Space Agency, was conducted to explore Saturn and its system (rings and satellites) to expand our understanding of the planet. An unexpected benefit of this mission was the discovery about Saturn’s moon Enceladus, a natural satellite covered in ice. On this icy moon’s south pole were cracks that spat out flumes of gas and ice from an underground ocean beneath its thick crust of ice.

astronomy saturn planet space moon rings — Saturn, the sixth planet in the solar system

And where water exists lives the potential for life. Simple unicellular organisms like the bacteria Sphingopyxis alaskensis have the potential to live in such cold aquatic environments low in nutrients. Such capability to theoretically weather and survive in extreme conditions like those of Enceladus makes it or a similar organism a possible candidate for life there. Enceladus was found to contain phosphate, salts, and carbon-based organic material in addition to all of its water, making it an even more likely location for potential life like that of Earth’s. If bacterial organisms like the Earth species proposed do live on Enceladus, they must be coated in a lipid membrane. Lipids are known to be hydrophobic (repelled by water) and would thus form a skin on the surface of the water of Enceladus rather than sinking to the bottom, out of the reach of material jettisoned into the air by the plumes.

As the ocean is exposed to the vacuum of space by the cracks at the south pole, the ocean would boil and the resultant jets would send the cellular material into the air. Another benefit of this proposal is the size of the organism. The small size of unicellular organisms would allow them to fit on the ice grains that fly out from Enceladus's ocean on its plumes. The perfect spacecraft is set to take off this October, NASA’s Europa Clipper. Though the Clipper is meant to explore Jupiter’s moon, Europa, its instruments are well suited for the task of identifying the possibility of life in the ice grains of Enceladus. The SUrface Dust Analyzer on Europa, a marvel of technology, has the ability to detect biological material in a single ice grain out of hundreds of thousands. Rather than averaging results across a large sample with a large quantity of ice grains, a single grain is found to provide better results as a biomaterial is concentrated

within that singular piece.

jupiter space red dot astronomy planet solar system — Jupiter, the fifth planet in the solar system

The SUrface Dust Analyzer and instruments to come have or will have the ability to identify molecules with negative charges, making them well suited for the detection of fatty acids and lipids (both prevalent cellular material in simple bacteria). Such technology will make the detection of life through biological material far easier than in the past by providing concrete evidence. Though if such life or evidence is present at the surface of water bodies is uncertain, as is the presence of life itself, by taking this step to identify potential life, science can at the very least rule out places where life does not exist. By looking at the icy moons of Saturn and Jupiter through such advanced instruments, we open science to learning more about our solar system and answering the question once and for all: are humans alone in the universe?