The search for extraterrestrial life is advancing, and scientists may have a promising new candidate. A recent study focuses on Saturn’s largest moon, Titan, revealing it possesses both the building blocks of life and a potential energy source to sustain them. Researchers examined data from NASA’s Cassini mission, which had detected a massive plume of ice grains and water vapor emanating from Titan’s icy crust, along with carbon in the form of methane gas. Notably, the plume contained high levels of hydrogen cyanide—a molecule known to contribute to the formation of organic compounds such as amino acids.
These chemicals are the foundation of life as we know it, but they need to form a protein chain to become alive. The molecules must bond into a structure that can take in nutrient molecules to do this. The scientists believe that the presence of hydrogen cyanide suggests that life could exist within a subsurface ocean on Titan if the chemical can move from the surface to the ocean.
Scientists have long suspected that Titan has an internal ocean, but it has been difficult to confirm this. However, their latest research indicates that it is much more likely. The chemistry of the planet is very similar to Earth’s, so it is possible that microorganisms living in our oceans could also thrive there. The polar region of Titan is warmer than the rest, suggesting it is a good candidate for a body of water. The team is working to understand if the ocean of Titan is influenced by thermal vents, which would help it stay warm and prevent it from freezing.
A methane bubble trapped beneath the ice may be warming the ocean, as the gas releases heat when it reaches the surface. This could be enough to sustain a microbial population, even though Titan is at a frigid -290 degrees Fahrenheit.
The researchers have also found evidence that the methane bubble is surrounded by an insulated layer of clathrate ice up to six miles thick. This could explain how methane gas generates such a massive atmosphere.
Other clues point to a subsurface ocean on Titan, as well. Astronomers have observed mysterious regions in the ice, described as “magic islands.” These features might be clumps of nitrogen gas, floating organic material like pumice that can float on the water here on Earth or even waves. However, the team believes they are more likely to be tectonic features caused by the movement of the underlying liquid methane.
Scientists have also spotted that the impact craters on Titan are hundreds of meters shallower than expected, and only 90 have been identified. This may be because the clathrate crust is 10 km thick instead of the 5-10 km expected. The next step in this mystery is to send a spacecraft to Titan, which should be able to probe the depths of the lakes on the equator and at the poles. When that spacecraft, Dragonfly, arrives on the icy moon in 2034, planetary scientists and biochemists should have prepared a wish list of molecules to look for.
