Space Daily] NASA scientists have definitively detected the chemical acrylonitrile in the atmosphere of Saturn's moon Titan, a place that has long intrigued scientists investigating the chemical precursors of life.
On Earth, acrylonitrile, also known as vinyl cyanide, is useful in the
manufacture of plastics. Under the harsh conditions of Saturn's largest
moon, this chemical is thought to be capable of forming stable, flexible
structures similar to cell membranes. Other researchers have previously
suggested that acrylonitrile is an ingredient of Titan's atmosphere,
but they did not report an unambiguous detection of the chemical in the
smorgasbord of organic, or carbon-rich, molecules found there.
Now, NASA researchers have identified the chemical fingerprint of
acrylonitrile in Titan data collected by the Atacama Large
Millimeter/submillimeter Array (ALMA) in Chile. The team found large
quantities of the chemical on Titan, most likely in the stratosphere -
the hazy part of the atmosphere that gives this moon its brownish-orange
"We found convincing evidence that acrylonitrile is present in Titan's
atmosphere, and we think a significant supply of this raw material
reaches the surface," said Maureen Palmer, a researcher with the Goddard
Center for Astrobiology at NASA's Goddard Space Flight Center in
Greenbelt, Maryland, and lead author of a July 28, 2017, paper in
The cells of Earth's plants and animals would not hold up well on Titan,
where surface temperatures average minus 290 degrees Fahrenheit (minus
179 degrees Celsius), and lakes brim with liquid methane.
In 2015, university scientists tackled the question of whether any
organic molecules likely to be on Titan could, under such inhospitable
conditions, form structures similar to the lipid bilayers of living
cells on Earth. Thin and flexible, the lipid bilayer is the main
component of the cell membrane, which separates the inside of a cell
from the outside world. This team identified acrylonitrile as the best
Those researchers proposed that acrylonitrile molecules could come
together as a sheet of material similar to a cell membrane. The sheet
could form a hollow, microscopic sphere that they dubbed an "azotosome."
This sphere could serve as a tiny storage and transport container, much
like the spheres that lipid bilayers can form.
"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, which is
funded by the NASA Astrobiology Institute. "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." Read More