Washington-Scientists studying the atmosphere of Saturn’s largest moon Titan have discovered ‘large quantities’ of a chemical that could be an ‘important step on the pathway of life.’ On Earth, the chemical known as vinyl cyanide is used in the process of creating plastics – but, in the harsh environment of Titan, it could form flexible membrane-like structures similar to those surrounding animal and plant cells. The researchers say they have ‘definitively detected’ the material, and they suspect a large amount of it may even reach the surface.

We found convincing evidence that acrylonitrile [vinyl cyanide] is present in Titan’s atmosphere, and we think a significant supply of this raw material reaches the surface,’ said lead author Maureen Palmer, a researcher with the Goddard Center for Astrobiology at NASA’s Goddard Space Flight Center.

Previous research determined that vinyl cyanide, or acrylonitrile, could come together to create a sheet like a cell membrane.

This could then form a hollow, microscopic sphere called an azotosome, which would act as a storage and transport container, like the structures formed by lipid bilayers on Earth’s cells.

The lipid bilayer is a key part of the cell membrane, and according to NASA, vinyl cyanide could serve a similar function on Titan. ‘The ability to form a stable membrane to separate the internal environment from the external one is important because it provides a means to contain chemicals long enough to allow them to interact,’ said Michael Mumma, director of the Goddard Center for Astrobiology.

‘If membrane-like structures could be formed by vinyl cyanide, it would be an important step on the pathway to life on Saturn’s moon Titan.’

While scientists were previously unable to make an unambiguous detection of the chemical, the new study using data from the Atacama Large Millimetre/submillimetre Array (ALMA) in Chile found that it is ‘plentiful’ in the large moon’s atmosphere, in particular, the stratosphere.

The scientists estimate it is most abundant in the stratosphere, at about 125 miles up.

But, as it travels to the cold lower atmosphere, it condenses, causing it to rain down onto the surface.Using the new data, the team calculated how much material could be deposited in Titan’s second-largest lake, Ligeia Mare.

This lake takes up about the same surface area of Earth’s Lake Huron and Lake Michigan combined, according to Nasa. In the span of Titan’s lifetime, it could have accumulated enough acrylonitrile to firm roughly 10 million azotosomes in every millimeter, or quarter-teaspoon, of liquid.

On Earth, there are about a million bacteria per millimetre of coastal ocean water, the researchers note.

‘The detection of this elusive, astrobiologically relevant chemical is exciting for scientists who are eager to determine if life could develop on icy worlds such as Titan,’ said Goddard scientist Martin Cordiner, senior author on the paper.

‘This finding adds an important piece to our understanding of the chemical complexity of the solar system.’