An international team of planetary scientists has detected vinyl cyanide in the atmosphere of Titan, Saturn’s largest moon, which is exciting news. If life is possible on Titan, then it's likely this molecule plays an important role in it.
The research, published in Science Advances and led by NASA's Goddard Space Flight Center, estimates there are around 100,000 billion molecules in every cubic centimeter of the atmosphere. While that figure might seem extremely large, it corresponds to about one-millionth a percent of the moon’s atmospheric composition. But if the conditions are right, even this tiny percentage could be impactful.
With a temperature of around -180°C (-290°F) and a dense nitrogen atmosphere, Titan is not a welcoming world for life as we know it. But despite that, researchers have been toying with what simple life forms could look like on the Saturnian moon, with vinyl cyanide being suggested as a good molecule to build cell-like membranes.
On Earth, cell membranes are made of fatty molecules, so-called lipids, but these wouldn’t be able to form on a frigid world like Titan. Instead, vinyl cyanide could be used to form cell membranes.
This was all theoretical until hints of the molecules were observed by Cassini, triggering the curiosity of scientists. Further simulations showed that vinyl cyanide can form stable membranes in a Titan-like environment.
Researchers used the Atacama Large Millimeter/submillimeter Array (ALMA) to study the atmosphere of Titan. ALMA collected observations from February to May 2014, and with that data researchers were able to confirm the presence of vinyl cyanide. The molecules were found mostly at altitudes of more than 200 kilometers (125 miles), matching the expected model of the atmosphere of Titan.
If the molecules rain down on the moon, they are likely to end up in one of the many methane lakes and seas. The team estimate that if cell membranes were forming on Titan, there would be 10 million per cubic centimeter in Ligeia Mare, Titan's second largest body of liquid. By comparison, there are about 1 million bacteria per cubic centimeter in coastal ocean waters on Earth.
Titan is the only other place in the Solar System where stable bodies of surface liquid have been found. This research could help launch many studies on how life sporting a vinyl cyanide membrane might form, live, and thrive on Titan.
Studies like this one also might help us understand the intricate connection between the moon's surface and atmosphere – and maybe help us nail down the possiblity of life.