Saturn’s moon Enceladus contains ingredients for the origins of life

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Scientists have long viewed Saturn’s moon Enceladus, which harbors an ocean beneath its thick icy crust, as one of Saturn’s moons. The best places to search for life outside Earth.

Now, a new analysis of data collected by NASA’s Cassini mission, which orbited Saturn and its moons between 2004 and 2017, has revealed intriguing evidence supporting the idea of ​​Enceladus as a habitable ocean world.

Enceladus first captured scientists’ attention in 2005 after observing plumes of ice grains and water vapor rising through cracks in the moon’s icy crust and shooting into space. The spacecraft flew past the plumes and “sampled” them, with data indicating the presence of organic compounds within the plumes, some of which are essential for life.

The latest analysis of data from Cassini’s flyby of Enceladus has revealed the discovery of a molecule called hydrogen cyanide, which is toxic to humans but important for the processes that give rise to life. Furthermore, the team also found evidence to support that Enceladus’s ocean contains organic compounds that provide a source of chemical energy that can be used as a powerful fuel for any form of life.

A study detailing the findings was published Thursday in the journal Nature astronomy.

“Our work provides further evidence that Enceladus hosts some of the molecules most important for forming the building blocks of life and sustaining that life through metabolic reactions,” said lead study author Jonah Peter, a doctoral student in biophysics at Harvard University. , in the current situation.

“Not only does Enceladus appear to meet the basic requirements for habitation, but we now have an idea about how complex biomolecules formed there, and what kind of chemical pathways might be involved.”

The necessary components of life as we know it on Earth include water, energy, and chemical elements. Peter said the new research provides scientists with chemical blueprints that can be tested in laboratories.

Amino acids are essential for life, and hydrogen cyanide is a versatile molecule that allows amino acids to be synthesized, according to the study authors.

“The discovery of hydrogen cyanide was particularly exciting, because it is the starting point for most theories about the origin of life,” Peter said. “The more we tried to poke holes in our results by testing alternative models, the stronger the evidence became.
Eventually, it became clear that there was no way to match the column composition without including hydrogen cyanide.

Previously, there were molecules such as carbon dioxide, methane, molecular hydrogen, water and ammonia It was discovered in the plumes of EnceladusWhich reflects the composition of the ocean beneath the ice crust that generates the plumes.

The combination of these elements together suggests that a process called methanogenesis, or metabolic methane creation, may be influencing Enceladus. Scientists suspect that methane generation may also have occurred on early Earth, contributing to the origin of life.

But the new research suggests that there are more diverse and powerful chemical energy sources within Enceladus’s ocean. In addition to hydrogen cyanide, organic compounds detected in the analysis included acetylene, propylene and ethane along with traces of alcohols such as methanol and molecular oxygen, suggesting that there is more than one way to sustain life within the ocean world.

“If methane generation is like a small watch battery, in terms of energy, then our results suggest that Enceladus’s ocean may offer something akin to a car battery, capable of providing a significant amount of energy for any life that might exist.” Kevin Hand, study co-author and deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement:

Now, the study authors want to investigate the extent to which organic compounds are diluted within the subsurface ocean, because dilution of these compounds could determine whether Enceladus could support life.

In the future, astronomers hope to send A A mission dedicated to investigating EnceladusWhich could provide a definitive answer about whether life exists in the ocean world.

Although the Cassini mission ended six years ago, its data remains a treasure trove of new information.

“(The mission’s) observations continue to provide us with new insights into Saturn and its moons — including the mysterious Enceladus,” Tom Nordheim, study co-author and a JPL planetary scientist who worked on the Cassini mission, said in a statement.