By Amy R. Babcock
Although the Cassini mission ended in September 2017, the data collected is still being examined by scientists. So much had been transmitted by the probe that it will take decades to sift through it all. Recently, a science team led by Nozair Khawaja of the Free University of Berlin, were studying some of this data collected by the spacecraft’s Cosmic Dust Analyzer (CDA), which detected ice grains emitted from Enceladus into Saturn’s E Ring. The scientists used the CDA’s mass spectrometer measurements to determine the composition of the material in the grains.
Powerful hydrothermal vents regularly eject material from the core of Enceladus. This material mixes with water from the moon’s massive subsurface ocean and then is released into space as water vapor and ice grains. The team discovered new molecules condensed into the ice grains that turned out to be nitrogen and oxygen bearing compounds. These compounds were determined to be organic, the ingredients of amino acids.
Here on Earth, similar compounds are part of a chemical reactions that also produce these building blocks of life. Hydrothermal vents on our ocean floor provide the heat and energy that fuels these reactions. This lends to the belief that the hydrothermal vents on Enceladus might operate in the same way, by supplying the energy needed to produce amino acids. And now, these organic compounds have been verified in the plumes of Enceladus.
“If the conditions are right, these molecules coming from the deep ocean of Enceladus could be on the same reaction pathway as we see here on Earth. We don’t yet know if amino acids are needed for life beyond Earth but finding the molecules that form amino acids is an important piece of the puzzle,” said Khawaja, whose findings were published October 2nd in the Monthly Notices of the Royal Astronomical Society.
These new findings work to complement the discovery made by the team last year of large, insoluble complex organic molecules that are believed to float on the surface of Enceladus’ ocean. These finding are what prompted the team to dive deeper with this recent work. Their goal was to hopefully find the ingredients, dissolved in the ocean, that would be needed to form amino acid formation.
“Here we are finding smaller and soluble organic building blocks – potential precursors for amino acids and other ingredients required for life on Earth,” said co-author Jon Hillier.
“This work shows that Enceladus’ ocean has reactive building blocks in abundance, and it’s another green light in the investigation of the habitability of Enceladus,” added co-author Frank Postberg.
Cassini-Huygens is a mission cooperative project of NASA, the European Space Agency (ESA), and the Italian Space Agency. NASA’s Jet Propulsion Laboratory (JPL) manages the mission for NASA’s Science Mission Directorate, Washington. To learn more about the mission and the science learned from its data, visit the official website.