Titan has molecules that could form cell membranes

Scientists have found evidence that Saturn's moon Titan harbors a possible ingredient for life.
By Kathy Fey | Jul 29, 2017
A new study suggests that Saturn's moon Titan contains an important building block for life.

Space.com reports that the satellite's dense atmosphere contains a significant amount of vinyl cyanide molecules, which could play a key role in the formation of cell membranes. Such membranes could possibly form around cells in the vast methane lakes that appear all over Titan.

Scientists have considered Titan's liquid-hydrocarbon seas to be possibly life-supporting for some time. Titan contains a number of complex organic compounds that contain carbon, although life on Titan would be reliant on liquid methane rather than the liquid water on which Earth organisms rely.

Cell membranes that exist on Earth are made of molecules called lipids, which would not survive in Titan's atmosphere and frigid temperatures. According to computer models, cell membranes could exist on Titan if they were made of vinyl cyanide.

Using data collected by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers found vinyl cyanide in Titan's atmosphere. Moreover, the data suggest that enough vinyl cyanide has fallen into Titan's seas to form about ten million membranes per cubic centimeter of liquid methane about ten times the bacterial population of Earth's coastal waters.

"It's definitely a rough estimate because there are just so many things we don't know about Titan," lead author Maureen Palmer of NASA's Goddard Space Flight Center said. "It can help lead us along to a better understanding of Titan's chemistry and what sort of increasingly complex molecules can be found there."

Adding to the growing body of evidence that Titan might be able to harbor life are recent findings by the Cassini-Huygens mission. The Cassini space probe found Titan populated with negatively charged ions, called anions, which should combine quickly with other molecules. Moreover, some of the ions have been identified as carbon chain anions, which may have played a key role in the emergence of life on Earth.

"These inspiring results from Cassini show the importance of tracing the journey from small to large chemical species in order to understand how complex organic molecules are produced in an early Earth-like atmosphere," Nicolas Altobelli of the European Space Agency said. "While we haven't detected life itself, finding complex organics not just at Titan but also in comets and throughout the interstellar medium [means] we are certainly coming close to finding its precursors."

The study was published in the journal Science Advances.

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