On Earth, most cellular membranes consist of a category of fatty molecules known as lipids. However, lipids won’t work as a protective layer for cells on Saturn’s moon, Titan, due to its hydrocarbon-rich weather system and extreme temperatures that average negative 290 degrees Fahrenheit (negative 180 degrees Celsius). A team of scientists believe that they have found an alternative molecule that could stand in as a cellular membrane on Titan by running computer simulations using Titan’s conditions.
The Cassini probe had previously detected hints of this molecule, known as vinyl cyanide (C2H3CN), in Titan’s atmosphere. The presence of vinyl cyanide was confirmed using data from a more Earth-bound source: the Atacama Large Millimeter/submillimeter Array (ALMA), a network of radio telescopes in northern Chile. The research team had analyzed this data in 2014 and their findings were published in Science Advances on July 28 this year.
Based on this data, the team estimates that there is enough vinyl cyanide in Titan’s seas to form 10 million cellular membranes per cubic centimeter. As study lead author Maureen Palmer noted, “It’s definitely a rough estimate, because there are just so many things we don’t know about Titan.”
This does add to the probability that Titan could host life, however. On July 26th, a separate research team had published a study announcing the discovery of carbon chain anions in The Astrophysical Journal Letters. These negatively charged particles are highly reactive and many scientists theorize that similar anions could have contributed to the rise of complex life on Earth.
The presence of carbon chain anions and vinyl cyanide is not the “smoking gun” that means that life definitely exists on Titan, but scientists are intrigued by the presence of complex organic molecules that could count as the precursors to life elsewhere in the solar system. Scientists believe that Titan’s atmosphere is similar to the type of atmosphere that Earth had billions of years ago, when life could have first appeared on our planet.
The Cassini probe is unlikely to discover that life, as it is currently in the middle of its “grand finale” of 22 relatively rapid orbits around Saturn. Cassini’s mission will end on September 15, 2017, with a spectacular dive into Saturn’s atmosphere. However, NASA and the European Space Agency are currently planning future missions to the outer solar system that could include visits to Jupiter and Saturn and the possibility of more detailed studies of Titan’s environment.