Saturn’s moon offers glimpse of Earth’s past

Observations confirm the presence of a membrane-forming chemical in Titan’s atmosphere, resembling cell membranes of living organisms on Earth.

Artist impression Titan Saturn

Artist’s impression of Titan’s complex atmosphere. Credit: B. Saxton (NRAO/AUI/NSF); NASA

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Astronomers have discovered evidence of molecules on Saturn’s largest moon Titan that could lead to the development of life, with the detection of vinyl cyanide in its upper atmosphere.

Under the right conditions, the organic molecule vinyl cyanide could coalesce into microscopic spheres resembling cell membranes.

Methane is known to rain down onto the icy surfaces of Titan and into rivers, lakes and seas.

These pools of hydrocarbons create a unique environment that may help molecules of vinyl cyanide link together to form membrane features resembling the cell membranes of living organisms on Earth.

Astronomers studying data from the Atacama Large Millimeter/submillimeter Array telescope (ALMA) in early 2014 have found compelling evidence that molecules of vinyl cyanide are present on Titan.

“The presence of vinyl cyanide in an environment with liquid methane suggests the intriguing possibility of chemical processes that are analogous to those important for life on Earth,” says Maureen Palmer of NASA’s Goddard Space Flight Center and lead author of the study.

Titan’s atmosphere is a chemical melting pot.

Through harnessing energy from the Sun and fast moving particles that orbit Saturn, simple organic molecules are able to convert into larger, more complex chemicals.

However, this does not mean that the conditions on Titan are right for the development of life as we know it.

“As our knowledge of Titan’s chemistry grows, it becomes increasingly apparent that complex molecules arise naturally in environments similar to those found on the early Earth, but there are important differences,” says Martin Cordiner, also with NASA’s Goddard Space Flight Center and a co-author on the paper.

One important difference between Earth and Titan to consider is Titan’s surface temperature of -178°C, which is colder than Earth at any point in our planet’s history.

At this temperature, all water on Titan’s surface remains completely frozen.

Further, geological evidence also suggests that the early Earth’s surface was highly active with volcanism; however Titan’s icy crust appears quite calm.

“We are continuing to use ALMA to make further observations of Titan’s atmosphere,” concludes Conor Nixon, also of NASA’s Goddard Space Flight Center and a co-author on the paper.

“We are looking for new and more complex organic chemicals as well as studying this moon’s atmospheric circulation patterns.

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In the future, higher-resolution studies will shed more light on this intriguing world and hopefully give us new insights into Titan’s potential for prebiotic chemistry.”