Saturn’s moon Enceladus continues to look like a promising world for life outside of Earth. Thanks to investigations from the Cassini mission we have learned that in its subsurface ocean there is geothermal activity and organic compounds. In a new study, researchers have announced the discovery of some new kinds of organic compounds found.
After last year's discovery of carbon-rich molecules, and the previous discovery of hydrocarbons, researchers have announced the discovery of small soluble organic molecules, such as amines, in plumes spurting out from the moon. These molecules are the building blocks of amino acids, in turn, the building blocks of proteins.
"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," lead author Nozair Khawaja, who led the research team of the Free University of Berlin, said in a statement. Their findings are published in the Monthly Notices of the Royal Astronomical Society.
The new organics, observed by Cassini’s Cosmic Dust Analyzer (CDA), were found to be nitrogen- and oxygen-bearing compounds. Hydrothermal vents eject material from the core, which mix with water from Enceladus' subsurface ocean and get spat out as ice crystals. The compounds were likely to have deposited on the ice crystals within the surface fissures. The plumes then blast these ice grains into space and form Saturn’s E-ring.
The ice crystals in the ring are a treasure trove of data for CDA, which is why two years after the mission ended, new discoveries are still being made about the Saturn system.
"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.
The complexity of the chemistry on Enceladus is obviously exciting as it's suggestive of the potential habitability of the frozen moon, but it is still extraordinary, even if it turns out that life didn’t develop there.
Cassini was a collaborative mission between NASA, the European Space Agency, and the Italian Space Agency. It reached Saturn in July 2004 and it continued to study the system until its grand finale swan dive into the gas giant in September 2017. The fiery death was necessary to guarantee that we don’t accidentally contaminate potential life-bearing worlds such as Enceladus.