Hydrocarbons are organic molecules, and the fact that they exist in large quantities on Titan suggests that life could take root there under the right conditions.
"If you had lightning taking place in the atmosphere of Titan, you could make what we call precursor molecules," said Bada, who was not involved with Morente's study.
"To go any further than that," he said, "you need liquid water."
Titan's water is currently frozen into chunks as hard as granite. If those ice "rocks" were to melt, however, the environment could become more hospitable to the building blocks of life.
With liquid water, the planet could host the formation of amino acids and then full proteins, which drive all biochemistry and set the stage for more complex molecules.
"I look at Titan as a big, frozen, prebiotic casserole," Bada said, referring to the state before the emergence of life.
"The idea that life could be widespread in the universe, I think, is very credible."
A Field of Its Own
Advocates of theories about life on Titan note that various celestial events could temporarily warm up the moon enough to melt its ice into water.
Perhaps this happened in the past, they say—or it could happen in the future.
But study author Morente said it's impossible to precisely assess such possibilities with the scientific knowledge available today.
What astronomers do know is that Titan does not have its own magnetic field, he said. The moon instead orbits within Saturn's magnetosphere at differing distances from the planet.
This means that the strength of Titan's magnetic field is constantly changing, leaving its surface more vulnerable to damaging cosmic rays.
Without stable protection from radiation, Morente said, "the existence of life is very unlikely."
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