A team of biologists from the United States, Canada, the United Kingdom, and France has explored the possibility of life on Saturn’s largest moon, Titan. They studied the moon’s unique characteristic of having an abundant amount of organic content in its subsurface ocean. The researchers, led by Dr. Antonin Affholder from the University of Arizona, used bioenergetic modeling to simulate the conditions that could support life on Titan.
Titan’s subsurface ocean is estimated to be around 483 km (300 miles) deep, and the team focused on a simple biological process called fermentation, which doesn’t require oxygen and could be similar to the early life on Earth. They specifically looked at the organic molecule glycine, which is the simplest amino acid and was abundant in the early Solar System.
The simulations showed that only a small fraction of Titan’s organic material may be suitable for microbial consumption, and that a steady supply of glycine from the surface is necessary to sustain life. However, the team found that the supply may only be sufficient to support a tiny population of microbes, weighing only a few kilograms at most, equivalent to the mass of a small dog. This would mean that the biosphere would average less than one cell per liter of water over the entire ocean.
The study suggests that Titan’s unique organic inventory may not be as available for life as scientists thought, and that finding life on the moon might be like searching for a needle in a haystack. The findings were published in the Planetary Science Journal and could have significant implications for future missions to Titan.