This icy moon orbiting Saturn is more alive than we thought

Photo illustration by Luis G. Rendon/The Daily Beast/Getty

Photo illustration by Luis G. Rendon/The Daily Beast/Getty

When NASA’s Cassini spacecraft visited Enceladus, Saturn’s sixth moon, in 2005, its observations led to a startling discovery.

The icy moon, 310 miles across, is not just another cold rock. He’s active – a real chemistry lab in space. The salty ocean sloshes under its icy crust. Holes in the ice, centered along the moon’s south pole, pump powerful chemicals hundreds of miles into space.

All this active chemistry has brought Enceladus near the top of the list of planets and moons in the solar system that may have the right conditions for simple life. But some key ingredients in microbial evolution seemed to be missing. Chief among them was hydrogen cyanide, sometimes called prussic acid, which is highly flammable, extremely poisonous, but also very useful on Earth as an ingredient in many industrial chemicals and pharmaceuticals.

More than 15 years after the spacecraft reached Enceladus, a team of scientists from Caltech and Harvard took a closer look at the piles of data collected by the spacecraft during its 10-year mission and concluded that initial readings were wrong. Enceladus if have hydrogen cyanide, claimed astrobiologists Jonah Peter and Kevin Hand and planetary scientist Tom Nordheim. And that bodes well for hope that the icy moon is home to alien life.

Is this icy moon our best chance of finding alien life?

“Our results indicate the presence of a rich, chemically diverse environment that may support complex organic synthesis and possibly even the origin of life,” Peter, Hand and Nordheim wrote in a new, yet to be peer-reviewed study that appeared online on page 12. January. All three scientists are affiliated with Caltech and NASA’s Jet Propulsion Laboratory. Peter also works for Harvard.

The team’s findings may force scientists to continue to prioritize Enceladus as they intensify their search for alien life. It may even be given a higher priority than Mars, Venus and even Europa, a moon of Jupiter that has much in common with Enceladus and is a favored target for alien hunters.

This does not mean that first contact is imminent. At the moment, what scientists hope to confirm on Enceladus is clear conditions for life, somewhere beneath the moon’s cool crust. Checking all these chemical and environmental boxes could warrant new missions to the moon in the coming decades.

And it is these probes that can find very simple life forms: bacteria or other microbes. “I believe the prospects for microbial life beneath the surface of Enceladus or Europa are high,” Avi Loeb, a Harvard physicist who wasn’t involved in the Cassini reanalysis, told The Daily Beast.

Although Loeb warned, “I doubt if there are any dead fish on the icy surface.”

Biologists generally agree that simple organisms as we understand them require certain ingredients in certain combinations to evolve: carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus to begin with. There must be enough variability in the surrounding environment – basically elements move and mix – to provide energy for chemical reactions that mix, match and remix these elements until they produce something capable of eating, metabolizing, excreting, breathing, moving, growing, reproducing and react to external stimuli. That’s life.

There are important intermediate steps in this evolutionary process. And hydrogen cyanide—a compound of hydrogen, carbon, and ammonia with the chemical formula HCN—allows you to do one of these steps. “With HCN, biochemically important molecules such as amino acids can be built,” Dirk Schulze-Makuch, an astronomer at the Technical University Berlin, told The Daily Beast. Amino acids, in turn, can form the proteins that living cells need to function and reproduce.

Analyzing data from Cassini’s first flyby of Enceladus’s southern plumes, scientists quickly found traces of carbon, hydrogen, nitrogen, oxygen and sulfur. The plumes indicated variability—so among the basic ingredients of life, the moon lacked only a few things to evolve. One of them was hydrogen cyanide or something like that.

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View of Enceladus captured by NASA’s Cassini spacecraft.

NASA/JPL/Institute of Space Sciences

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View of Enceladus captured by NASA’s Cassini spacecraft.

NASA/JPL/Institute of Space Sciences

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View of Enceladus captured by NASA’s Cassini spacecraft.

NASA/JPL/Institute of Space Sciences

But the compound was there all the time – according to Peter, Hand and Nordheim, the scientists just didn’t notice it. “Identification of minor species in the plume remains an ongoing challenge,” they wrote, using the term “species” to refer to types of chemicals.

The problem is that Cassini’s Ion and Neutral Mass Spectrometer, a device that identifies chemicals by weighing their components, generated raw data that required careful analysis. As our analytical techniques improve, scientists are only now able to extract new discoveries from old data. This is exactly what happened when Peter, Hand, and Nordheim went through the Enceladus files again. “The authors were able to squeeze a little more out of the dataset,” Frank Postberg, a planetary scientist at Freie Universität Berlin, told The Daily Beast.

It is still possible that the discoveries of Peter, Hand and Nordheim fall apart through peer review or further research by different teams. And even if they Down wait, we are still far from confirming the conditions for evolution on Enceladus.

What’s next for NASA’s Cassini mission space explorers?

First, we’re still missing something. “Phosphorus and sulfur are essential ingredients for life as we know it,” Postberg noted. “Phosphorus has not yet been detected on Enceladus, and sulfur only tentatively.”

It’s possible that traces of phosphorus and more pronounced traces of sulfur are hiding in the old Cassini data, as is hydrogen cyanide. His too it is possible that someone needs to send new and better probes to the moon for more data. “We would probably need a new mission with an instrument … focused on detecting large organic molecules,” said Schulze-Makuch.

A mass spectrograph with an additional gas chromatograph — a device that burns chemicals to analyze them — would be a useful feature for the new Enceladus probe, Schulze-Makuch said.

This hypothetical probe may be able to confirm in Enceladus’s plumes the presence or absence of essential ingredients of evolution on the Moon itself. Continuing the mission can then start the search result of this evolution: the tiny organisms that live, die and reproduce in the subterranean sea of ​​Enceladus.

It would be an expensive undertaking. Cassini cost $3 billion – and that was almost 20 years ago. Future missions to Enceladus could be even more expensive.

The work of Peter, Hand and Nordheim is a case for investment. Saturn’s sixth moon is looking better and better as the first place we might find alien life. However, “a more detailed study of Enceladus’ ocean material,” the trio wrote, “will require future robotic missions.”

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