Scientists have long believed that Saturn's moon Enceladus, which hides an ocean beneath its thick icy shell, is one of the best places to look for life beyond Earth.
Now, a new analysis of data collected by NASA's Cassini mission, which orbited Saturn and its moons between 2004 and 2017, has found intriguing evidence that further supports the idea of Enceladus as a habitable ocean world.
Enceladus first caught the attention of scientists in 2005, as plumes of ice grains and water vapor were observed rising through cracks in the moon's icy mantle and being released into space. The spacecraft flew through the plumes and took "samples" of them, and the data showed the presence of organic compounds in the plumes, some of which are key to life.
The latest analysis of data from Cassini flybys of Enceladus revealed the discovery of a molecule called hydrogen cyanide, which is toxic to humans but crucial to the processes that determine the origin of life. What's more, the team also found evidence to support that Enceladus' ocean contains organic compounds that provide a source of chemical energy that could potentially be used as a powerful fuel for any life form.
The study describing the results was published in the journal Nature Astronomy.
"Our work provides further evidence that Enceladus hosts some of the most important molecules for both creating the building blocks of life and sustaining that life through metabolic reactions," lead study author Jonah Peters said in a statement. PhD student in biophysics at Harvard University.
"Not only does Enceladus appear to meet the basic requirements for habitability, but we now have an idea of how complex biomolecules might form there and what chemical pathways might be involved."
The ingredients necessary for life as we know it on Earth include water, energy, and chemical elements. The new research provides scientists with chemical designs that can be tested in labs, Peter says.
According to the authors of the study, amino acids are one of the building blocks of life, and hydrogen cyanide is considered a universal molecule that allows the formation of amino acids.
"The discovery of hydrogen cyanide was particularly exciting because it is the starting point for most theories of the origin of life," says Peter.
Molecules such as carbon dioxide, methane, molecular hydrogen, water, and ammonia have previously been found in Enceladus' plumes, which reflect the composition of the ocean beneath the icy shell that generated the plumes.
The combination of these elements together suggests that a process called methanogenesis, or the metabolic creation of methane, may be present on Enceladus. Scientists suspect that methanogenesis may have also occurred on the early Earth, contributing to the origin of life./BGNES
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